1 files changed, 1677 insertions, 339 deletions

diff --git a/tools/lguest/lguest.c b/tools/lguest/lguest.c
index 32cf2ce15d69..e44052483ed9 100644
--- a/tools/lguest/lguest.c
+++ b/tools/lguest/lguest.c
@@ -41,6 +41,8 @@
 #include <signal.h>
 #include <pwd.h>
 #include <grp.h>
+#include <sys/user.h>
+#include <linux/pci_regs.h>
 
 #ifndef VIRTIO_F_ANY_LAYOUT
 #define VIRTIO_F_ANY_LAYOUT             27
@@ -61,12 +63,19 @@ typedef uint16_t u16;
 typedef uint8_t u8;
 /*:*/
 
-#include <linux/virtio_config.h>
-#include <linux/virtio_net.h>
-#include <linux/virtio_blk.h>
-#include <linux/virtio_console.h>
-#include <linux/virtio_rng.h>
+#define VIRTIO_CONFIG_NO_LEGACY
+#define VIRTIO_PCI_NO_LEGACY
+#define VIRTIO_BLK_NO_LEGACY
+#define VIRTIO_NET_NO_LEGACY
+
+/* Use in-kernel ones, which defines VIRTIO_F_VERSION_1 */
+#include "../../include/uapi/linux/virtio_config.h"
+#include "../../include/uapi/linux/virtio_net.h"
+#include "../../include/uapi/linux/virtio_blk.h"
+#include "../../include/uapi/linux/virtio_console.h"
+#include "../../include/uapi/linux/virtio_rng.h"
 #include <linux/virtio_ring.h>
+#include "../../include/uapi/linux/virtio_pci.h"
 #include <asm/bootparam.h>
 #include "../../include/linux/lguest_launcher.h"
 
@@ -91,13 +100,16 @@ static bool verbose;
 /* The pointer to the start of guest memory. */
 static void *guest_base;
 /* The maximum guest physical address allowed, and maximum possible. */
-static unsigned long guest_limit, guest_max;
+static unsigned long guest_limit, guest_max, guest_mmio;
 /* The /dev/lguest file descriptor. */
 static int lguest_fd;
 
 /* a per-cpu variable indicating whose vcpu is currently running */
 static unsigned int __thread cpu_id;
 
+/* 5 bit device number in the PCI_CONFIG_ADDR => 32 only */
+#define MAX_PCI_DEVICES 32
+
 /* This is our list of devices. */
 struct device_list {
         /* Counter to assign interrupt numbers. */
@@ -106,30 +118,50 @@ struct device_list {
         /* Counter to print out convenient device numbers. */
         unsigned int device_num;
 
-        /* The descriptor page for the devices. */
-        u8 *descpage;
-
-        /* A single linked list of devices. */
-        struct device *dev;
-        /* And a pointer to the last device for easy append. */
-        struct device *lastdev;
+        /* PCI devices. */
+        struct device *pci[MAX_PCI_DEVICES];
 };
 
 /* The list of Guest devices, based on command line arguments. */
 static struct device_list devices;
 
-/* The device structure describes a single device. */
-struct device {
-        /* The linked-list pointer. */
-        struct device *next;
+struct virtio_pci_cfg_cap {
+        struct virtio_pci_cap cap;
+        u32 pci_cfg_data; /* Data for BAR access. */
+};
 
-        /* The device's descriptor, as mapped into the Guest. */
-        struct lguest_device_desc *desc;
+struct virtio_pci_mmio {
+        struct virtio_pci_common_cfg cfg;
+        u16 notify;
+        u8 isr;
+        u8 padding;
+        /* Device-specific configuration follows this. */
+};
 
-        /* We can't trust desc values once Guest has booted: we use these. */
-        unsigned int feature_len;
-        unsigned int num_vq;
+/* This is the layout (little-endian) of the PCI config space. */
+struct pci_config {
+        u16 vendor_id, device_id;
+        u16 command, status;
+        u8 revid, prog_if, subclass, class;
+        u8 cacheline_size, lat_timer, header_type, bist;
+        u32 bar[6];
+        u32 cardbus_cis_ptr;
+        u16 subsystem_vendor_id, subsystem_device_id;
+        u32 expansion_rom_addr;
+        u8 capabilities, reserved1[3];
+        u32 reserved2;
+        u8 irq_line, irq_pin, min_grant, max_latency;
+
+        /* Now, this is the linked capability list. */
+        struct virtio_pci_cap common;
+        struct virtio_pci_notify_cap notify;
+        struct virtio_pci_cap isr;
+        struct virtio_pci_cap device;
+        struct virtio_pci_cfg_cap cfg_access;
+};
 
+/* The device structure describes a single device. */
+struct device {
         /* The name of this device, for --verbose. */
         const char *name;
 
@@ -139,6 +171,25 @@ struct device {
         /* Is it operational */
         bool running;
 
+        /* Has it written FEATURES_OK but not re-checked it? */
+        bool wrote_features_ok;
+
+        /* PCI configuration */
+        union {
+                struct pci_config config;
+                u32 config_words[sizeof(struct pci_config) / sizeof(u32)];
+        };
+
+        /* Features we offer, and those accepted. */
+        u64 features, features_accepted;
+
+        /* Device-specific config hangs off the end of this. */
+        struct virtio_pci_mmio *mmio;
+
+        /* PCI MMIO resources (all in BAR0) */
+        size_t mmio_size;
+        u32 mmio_addr;
+
         /* Device-specific data. */
         void *priv;
 };
@@ -150,12 +201,15 @@ struct virtqueue {
         /* Which device owns me. */
         struct device *dev;
 
-        /* The configuration for this queue. */
-        struct lguest_vqconfig config;
+        /* Name for printing errors. */
+        const char *name;
 
         /* The actual ring of buffers. */
         struct vring vring;
 
+        /* The information about this virtqueue (we only use queue_size on) */
+        struct virtio_pci_common_cfg pci_config;
+
         /* Last available index we saw. */
         u16 last_avail_idx;
 
@@ -199,6 +253,16 @@ static struct termios orig_term;
 #define le32_to_cpu(v32) (v32)
 #define le64_to_cpu(v64) (v64)
 
+/*
+ * A real device would ignore weird/non-compliant driver behaviour.  We
+ * stop and flag it, to help debugging Linux problems.
+ */
+#define bad_driver(d, fmt, ...) \
+        errx(1, "%s: bad driver: " fmt, (d)->name, ## __VA_ARGS__)
+#define bad_driver_vq(vq, fmt, ...)                            \
+        errx(1, "%s vq %s: bad driver: " fmt, (vq)->dev->name, \
+             vq->name, ## __VA_ARGS__)
+
 /* Is this iovec empty? */
 static bool iov_empty(const struct iovec iov[], unsigned int num_iov)
 {
@@ -211,7 +275,8 @@ static bool iov_empty(const struct iovec iov[], unsigned int num_iov)
 }
 
 /* Take len bytes from the front of this iovec. */
-static void iov_consume(struct iovec iov[], unsigned num_iov,
+static void iov_consume(struct device *d,
+                        struct iovec iov[], unsigned num_iov,
                         void *dest, unsigned len)
 {
         unsigned int i;
@@ -229,14 +294,7 @@ static void iov_consume(struct iovec iov[], unsigned num_iov,
                 len -= used;
         }
         if (len != 0)
-                errx(1, "iovec too short!");
-}
-
-/* The device virtqueue descriptors are followed by feature bitmasks. */
-static u8 *get_feature_bits(struct device *dev)
-{
-        return (u8 *)(dev->desc + 1)
-                + dev->num_vq * sizeof(struct lguest_vqconfig);
+                bad_driver(d, "iovec too short!");
 }
 
 /*L:100
@@ -309,14 +367,20 @@ static void *map_zeroed_pages(unsigned int num)
         return addr + getpagesize();
 }
 
-/* Get some more pages for a device. */
-static void *get_pages(unsigned int num)
+/* Get some bytes which won't be mapped into the guest. */
+static unsigned long get_mmio_region(size_t size)
 {
-        void *addr = from_guest_phys(guest_limit);
+        unsigned long addr = guest_mmio;
+        size_t i;
+
+        if (!size)
+                return addr;
+
+        /* Size has to be a power of 2 (and multiple of 16) */
+        for (i = 1; i < size; i <<= 1);
+
+        guest_mmio += i;
 
-        guest_limit += num * getpagesize();
-        if (guest_limit > guest_max)
-                errx(1, "Not enough memory for devices");
         return addr;
 }
 
@@ -547,9 +611,11 @@ static void tell_kernel(unsigned long start)
 {
         unsigned long args[] = { LHREQ_INITIALIZE,
                                  (unsigned long)guest_base,
-                                 guest_limit / getpagesize(), start };
-        verbose("Guest: %p - %p (%#lx)\n",
-                guest_base, guest_base + guest_limit, guest_limit);
+                                 guest_limit / getpagesize(), start,
+                                 (guest_mmio+getpagesize()-1) / getpagesize() };
+        verbose("Guest: %p - %p (%#lx, MMIO %#lx)\n",
+                guest_base, guest_base + guest_limit,
+                guest_limit, guest_mmio);
         lguest_fd = open_or_die("/dev/lguest", O_RDWR);
         if (write(lguest_fd, args, sizeof(args)) < 0)
                 err(1, "Writing to /dev/lguest");
@@ -564,7 +630,8 @@ static void tell_kernel(unsigned long start)
  * we have a convenient routine which checks it and exits with an error message
  * if something funny is going on:
  */
-static void *_check_pointer(unsigned long addr, unsigned int size,
+static void *_check_pointer(struct device *d,
+                            unsigned long addr, unsigned int size,
                             unsigned int line)
 {
         /*
@@ -572,7 +639,8 @@ static void *_check_pointer(unsigned long addr, unsigned int size,
          * or addr + size wraps around.
          */
         if ((addr + size) > guest_limit || (addr + size) < addr)
-                errx(1, "%s:%i: Invalid address %#lx", __FILE__, line, addr);
+                bad_driver(d, "%s:%i: Invalid address %#lx",
+                           __FILE__, line, addr);
         /*
          * We return a pointer for the caller's convenience, now we know it's
          * safe to use.
@@ -580,14 +648,14 @@ static void *_check_pointer(unsigned long addr, unsigned int size,
         return from_guest_phys(addr);
 }
 /* A macro which transparently hands the line number to the real function. */
-#define check_pointer(addr,size) _check_pointer(addr, size, __LINE__)
+#define check_pointer(d,addr,size) _check_pointer(d, addr, size, __LINE__)
 
 /*
  * Each buffer in the virtqueues is actually a chain of descriptors.  This
  * function returns the next descriptor in the chain, or vq->vring.num if we're
  * at the end.
  */
-static unsigned next_desc(struct vring_desc *desc,
+static unsigned next_desc(struct device *d, struct vring_desc *desc,
                           unsigned int i, unsigned int max)
 {
         unsigned int next;
@@ -602,7 +670,7 @@ static unsigned next_desc(struct vring_desc *desc,
         wmb();
 
         if (next >= max)
-                errx(1, "Desc next is %u", next);
+                bad_driver(d, "Desc next is %u", next);
 
         return next;
 }
@@ -613,21 +681,48 @@ static unsigned next_desc(struct vring_desc *desc,
  */
 static void trigger_irq(struct virtqueue *vq)
 {
-        unsigned long buf[] = { LHREQ_IRQ, vq->config.irq };
+        unsigned long buf[] = { LHREQ_IRQ, vq->dev->config.irq_line };
 
         /* Don't inform them if nothing used. */
         if (!vq->pending_used)
                 return;
         vq->pending_used = 0;
 
-        /* If they don't want an interrupt, don't send one... */
+        /*
+         * 2.4.7.1:
+         *
+         *  If the VIRTIO_F_EVENT_IDX feature bit is not negotiated:
+         *    The driver MUST set flags to 0 or 1. 
+         */
+        if (vq->vring.avail->flags > 1)
+                bad_driver_vq(vq, "avail->flags = %u\n", vq->vring.avail->flags);
+
+        /*
+         * 2.4.7.2:
+         *
+         *  If the VIRTIO_F_EVENT_IDX feature bit is not negotiated:
+         *
+         *     - The device MUST ignore the used_event value.
+         *     - After the device writes a descriptor index into the used ring:
+         *         - If flags is 1, the device SHOULD NOT send an interrupt.
+         *         - If flags is 0, the device MUST send an interrupt.
+         */
         if (vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT) {
                 return;
         }
 
+        /*
+         * 4.1.4.5.1:
+         *
+         *  If MSI-X capability is disabled, the device MUST set the Queue
+         *  Interrupt bit in ISR status before sending a virtqueue notification
+         *  to the driver.
+         */
+        vq->dev->mmio->isr = 0x1;
+
         /* Send the Guest an interrupt tell them we used something up. */
         if (write(lguest_fd, buf, sizeof(buf)) != 0)
-                err(1, "Triggering irq %i", vq->config.irq);
+                err(1, "Triggering irq %i", vq->dev->config.irq_line);
 }
 
 /*
@@ -646,6 +741,14 @@ static unsigned wait_for_vq_desc(struct virtqueue *vq,
         struct vring_desc *desc;
         u16 last_avail = lg_last_avail(vq);
 
+        /*
+         * 2.4.7.1:
+         *
+         *   The driver MUST handle spurious interrupts from the device.
+         *
+         * That's why this is a while loop.
+         */
+
         /* There's nothing available? */
         while (last_avail == vq->vring.avail->idx) {
                 u64 event;
@@ -679,8 +782,8 @@ static unsigned wait_for_vq_desc(struct virtqueue *vq,
 
         /* Check it isn't doing very strange things with descriptor numbers. */
         if ((u16)(vq->vring.avail->idx - last_avail) > vq->vring.num)
-                errx(1, "Guest moved used index from %u to %u",
-                     last_avail, vq->vring.avail->idx);
+                bad_driver_vq(vq, "Guest moved used index from %u to %u",
+                              last_avail, vq->vring.avail->idx);
 
         /* 
          * Make sure we read the descriptor number *after* we read the ring
@@ -697,7 +800,7 @@ static unsigned wait_for_vq_desc(struct virtqueue *vq,
 
         /* If their number is silly, that's a fatal mistake. */
         if (head >= vq->vring.num)
-                errx(1, "Guest says index %u is available", head);
+                bad_driver_vq(vq, "Guest says index %u is available", head);
 
         /* When we start there are none of either input nor output. */
         *out_num = *in_num = 0;
@@ -712,24 +815,73 @@ static unsigned wait_for_vq_desc(struct virtqueue *vq,
          * that: no rmb() required.
          */
 
-        /*
-         * If this is an indirect entry, then this buffer contains a descriptor
-         * table which we handle as if it's any normal descriptor chain.
-         */
-        if (desc[i].flags & VRING_DESC_F_INDIRECT) {
-                if (desc[i].len % sizeof(struct vring_desc))
-                        errx(1, "Invalid size for indirect buffer table");
+        do {
+                /*
+                 * If this is an indirect entry, then this buffer contains a
+                 * descriptor table which we handle as if it's any normal
+                 * descriptor chain.
+                 */
+                if (desc[i].flags & VRING_DESC_F_INDIRECT) {
+                        /* 2.4.5.3.1:
+                         *
+                         *  The driver MUST NOT set the VIRTQ_DESC_F_INDIRECT
+                         *  flag unless the VIRTIO_F_INDIRECT_DESC feature was
+                         *  negotiated.
+                         */
+                        if (!(vq->dev->features_accepted &
+                              (1<<VIRTIO_RING_F_INDIRECT_DESC)))
+                                bad_driver_vq(vq, "vq indirect not negotiated");
 
-                max = desc[i].len / sizeof(struct vring_desc);
-                desc = check_pointer(desc[i].addr, desc[i].len);
-                i = 0;
-        }
+                        /*
+                         * 2.4.5.3.1:
+                         *
+                         *   The driver MUST NOT set the VIRTQ_DESC_F_INDIRECT
+                         *   flag within an indirect descriptor (ie. only one
+                         *   table per descriptor).
+                         */
+                        if (desc != vq->vring.desc)
+                                bad_driver_vq(vq, "Indirect within indirect");
+
+                        /*
+                         * Proposed update VIRTIO-134 spells this out:
+                         *
+                         *   A driver MUST NOT set both VIRTQ_DESC_F_INDIRECT
+                         *   and VIRTQ_DESC_F_NEXT in flags.
+                         */
+                        if (desc[i].flags & VRING_DESC_F_NEXT)
+                                bad_driver_vq(vq, "indirect and next together");
+
+                        if (desc[i].len % sizeof(struct vring_desc))
+                                bad_driver_vq(vq,
+                                              "Invalid size for indirect table");
+                        /*
+                         * 2.4.5.3.2:
+                         *
+                         *  The device MUST ignore the write-only flag
+                         *  (flags&VIRTQ_DESC_F_WRITE) in the descriptor that
+                         *  refers to an indirect table.
+                         *
+                         * We ignore it here: :)
+                         */
+
+                        max = desc[i].len / sizeof(struct vring_desc);
+                        desc = check_pointer(vq->dev, desc[i].addr, desc[i].len);
+                        i = 0;
+
+                        /* 2.4.5.3.1:
+                         *
+                         *  A driver MUST NOT create a descriptor chain longer
+                         *  than the Queue Size of the device.
+                         */
+                        if (max > vq->pci_config.queue_size)
+                                bad_driver_vq(vq,
+                                              "indirect has too many entries");
+                }
 
-        do {
                 /* Grab the first descriptor, and check it's OK. */
                 iov[*out_num + *in_num].iov_len = desc[i].len;
                 iov[*out_num + *in_num].iov_base
-                        = check_pointer(desc[i].addr, desc[i].len);
+                        = check_pointer(vq->dev, desc[i].addr, desc[i].len);
                 /* If this is an input descriptor, increment that count. */
                 if (desc[i].flags & VRING_DESC_F_WRITE)
                         (*in_num)++;
@@ -739,14 +891,15 @@ static unsigned wait_for_vq_desc(struct virtqueue *vq,
                          * to come before any input descriptors.
                          */
                         if (*in_num)
-                                errx(1, "Descriptor has out after in");
+                                bad_driver_vq(vq,
+                                              "Descriptor has out after in");
                         (*out_num)++;
                 }
 
                 /* If we've got too many, that implies a descriptor loop. */
                 if (*out_num + *in_num > max)
-                        errx(1, "Looped descriptor");
-        } while ((i = next_desc(desc, i, max)) != max);
+                        bad_driver_vq(vq, "Looped descriptor");
+        } while ((i = next_desc(vq->dev, desc, i, max)) != max);
 
         return head;
 }
@@ -803,7 +956,7 @@ static void console_input(struct virtqueue *vq)
         /* Make sure there's a descriptor available. */
         head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
         if (out_num)
-                errx(1, "Output buffers in console in queue?");
+                bad_driver_vq(vq, "Output buffers in console in queue?");
 
         /* Read into it.  This is where we usually wait. */
         len = readv(STDIN_FILENO, iov, in_num);
@@ -856,7 +1009,7 @@ static void console_output(struct virtqueue *vq)
         /* We usually wait in here, for the Guest to give us something. */
         head = wait_for_vq_desc(vq, iov, &out, &in);
         if (in)
-                errx(1, "Input buffers in console output queue?");
+                bad_driver_vq(vq, "Input buffers in console output queue?");
 
         /* writev can return a partial write, so we loop here. */
         while (!iov_empty(iov, out)) {
@@ -865,7 +1018,7 @@ static void console_output(struct virtqueue *vq)
                         warn("Write to stdout gave %i (%d)", len, errno);
                         break;
                 }
-                iov_consume(iov, out, NULL, len);
+                iov_consume(vq->dev, iov, out, NULL, len);
         }
 
         /*
@@ -894,7 +1047,7 @@ static void net_output(struct virtqueue *vq)
         /* We usually wait in here for the Guest to give us a packet. */
         head = wait_for_vq_desc(vq, iov, &out, &in);
         if (in)
-                errx(1, "Input buffers in net output queue?");
+                bad_driver_vq(vq, "Input buffers in net output queue?");
         /*
          * Send the whole thing through to /dev/net/tun.  It expects the exact
          * same format: what a coincidence!
@@ -942,7 +1095,7 @@ static void net_input(struct virtqueue *vq)
          */
         head = wait_for_vq_desc(vq, iov, &out, &in);
         if (out)
-                errx(1, "Output buffers in net input queue?");
+                bad_driver_vq(vq, "Output buffers in net input queue?");
 
         /*
          * If it looks like we'll block reading from the tun device, send them
@@ -986,6 +1139,12 @@ static void kill_launcher(int signal)
         kill(0, SIGTERM);
 }
 
+static void reset_vq_pci_config(struct virtqueue *vq)
+{
+        vq->pci_config.queue_size = VIRTQUEUE_NUM;
+        vq->pci_config.queue_enable = 0;
+}
+
 static void reset_device(struct device *dev)
 {
         struct virtqueue *vq;
@@ -993,53 +1152,705 @@ static void reset_device(struct device *dev)
         verbose("Resetting device %s\n", dev->name);
 
         /* Clear any features they've acked. */
-        memset(get_feature_bits(dev) + dev->feature_len, 0, dev->feature_len);
+        dev->features_accepted = 0;
 
         /* We're going to be explicitly killing threads, so ignore them. */
         signal(SIGCHLD, SIG_IGN);
 
-        /* Zero out the virtqueues, get rid of their threads */
+        /*
+         * 4.1.4.3.1:
+         *
+         *   The device MUST present a 0 in queue_enable on reset. 
+         *
+         * This means we set it here, and reset the saved ones in every vq.
+         */
+        dev->mmio->cfg.queue_enable = 0;
+
+        /* Get rid of the virtqueue threads */
         for (vq = dev->vq; vq; vq = vq->next) {
+                vq->last_avail_idx = 0;
+                reset_vq_pci_config(vq);
                 if (vq->thread != (pid_t)-1) {
                         kill(vq->thread, SIGTERM);
                         waitpid(vq->thread, NULL, 0);
                         vq->thread = (pid_t)-1;
                 }
-                memset(vq->vring.desc, 0,
-                       vring_size(vq->config.num, LGUEST_VRING_ALIGN));
-                lg_last_avail(vq) = 0;
         }
         dev->running = false;
+        dev->wrote_features_ok = false;
 
         /* Now we care if threads die. */
         signal(SIGCHLD, (void *)kill_launcher);
 }
 
+static void cleanup_devices(void)
+{
+        unsigned int i;
+
+        for (i = 1; i < MAX_PCI_DEVICES; i++) {
+                struct device *d = devices.pci[i];
+                if (!d)
+                        continue;
+                reset_device(d);
+        }
+
+        /* If we saved off the original terminal settings, restore them now. */
+        if (orig_term.c_lflag & (ISIG|ICANON|ECHO))
+                tcsetattr(STDIN_FILENO, TCSANOW, &orig_term);
+}
+
+/*L:217
+ * We do PCI.  This is mainly done to let us test the kernel virtio PCI
+ * code.
+ */
+
+/* Linux expects a PCI host bridge: ours is a dummy, and first on the bus. */
+static struct device pci_host_bridge;
+
+static void init_pci_host_bridge(void)
+{
+        pci_host_bridge.name = "PCI Host Bridge";
+        pci_host_bridge.config.class = 0x06; /* bridge */
+        pci_host_bridge.config.subclass = 0; /* host bridge */
+        devices.pci[0] = &pci_host_bridge;
+}
+
+/* The IO ports used to read the PCI config space. */
+#define PCI_CONFIG_ADDR 0xCF8
+#define PCI_CONFIG_DATA 0xCFC
+
+/*
+ * Not really portable, but does help readability: this is what the Guest
+ * writes to the PCI_CONFIG_ADDR IO port.
+ */
+union pci_config_addr {
+        struct {
+                unsigned mbz: 2;
+                unsigned offset: 6;
+                unsigned funcnum: 3;
+                unsigned devnum: 5;
+                unsigned busnum: 8;
+                unsigned reserved: 7;
+                unsigned enabled : 1;
+        } bits;
+        u32 val;
+};
+
+/*
+ * We cache what they wrote to the address port, so we know what they're
+ * talking about when they access the data port.
+ */
+static union pci_config_addr pci_config_addr;
+
+static struct device *find_pci_device(unsigned int index)
+{
+        return devices.pci[index];
+}
+
+/* PCI can do 1, 2 and 4 byte reads; we handle that here. */
+static void ioread(u16 off, u32 v, u32 mask, u32 *val)
+{
+        assert(off < 4);
+        assert(mask == 0xFF || mask == 0xFFFF || mask == 0xFFFFFFFF);
+        *val = (v >> (off * 8)) & mask;
+}
+
+/* PCI can do 1, 2 and 4 byte writes; we handle that here. */
+static void iowrite(u16 off, u32 v, u32 mask, u32 *dst)
+{
+        assert(off < 4);
+        assert(mask == 0xFF || mask == 0xFFFF || mask == 0xFFFFFFFF);
+        *dst &= ~(mask << (off * 8));
+        *dst |= (v & mask) << (off * 8);
+}
+
+/*
+ * Where PCI_CONFIG_DATA accesses depends on the previous write to
+ * PCI_CONFIG_ADDR.
+ */
+static struct device *dev_and_reg(u32 *reg)
+{
+        if (!pci_config_addr.bits.enabled)
+                return NULL;
+
+        if (pci_config_addr.bits.funcnum != 0)
+                return NULL;
+
+        if (pci_config_addr.bits.busnum != 0)
+                return NULL;
+
+        if (pci_config_addr.bits.offset * 4 >= sizeof(struct pci_config))
+                return NULL;
+
+        *reg = pci_config_addr.bits.offset;
+        return find_pci_device(pci_config_addr.bits.devnum);
+}
+
+/*
+ * We can get invalid combinations of values while they're writing, so we
+ * only fault if they try to write with some invalid bar/offset/length.
+ */
+static bool valid_bar_access(struct device *d,
+                             struct virtio_pci_cfg_cap *cfg_access)
+{
+        /* We only have 1 bar (BAR0) */
+        if (cfg_access->cap.bar != 0)
+                return false;
+
+        /* Check it's within BAR0. */
+        if (cfg_access->cap.offset >= d->mmio_size
+            || cfg_access->cap.offset + cfg_access->cap.length > d->mmio_size)
+                return false;
+
+        /* Check length is 1, 2 or 4. */
+        if (cfg_access->cap.length != 1
+            && cfg_access->cap.length != 2
+            && cfg_access->cap.length != 4)
+                return false;
+
+        /*
+         * 4.1.4.7.2:
+         *
+         *  The driver MUST NOT write a cap.offset which is not a multiple of
+         *  cap.length (ie. all accesses MUST be aligned).
+         */
+        if (cfg_access->cap.offset % cfg_access->cap.length != 0)
+                return false;
+
+        /* Return pointer into word in BAR0. */
+        return true;
+}
+
+/* Is this accessing the PCI config address port?. */
+static bool is_pci_addr_port(u16 port)
+{
+        return port >= PCI_CONFIG_ADDR && port < PCI_CONFIG_ADDR + 4;
+}
+
+static bool pci_addr_iowrite(u16 port, u32 mask, u32 val)
+{
+        iowrite(port - PCI_CONFIG_ADDR, val, mask,
+                &pci_config_addr.val);
+        verbose("PCI%s: %#x/%x: bus %u dev %u func %u reg %u\n",
+                pci_config_addr.bits.enabled ? "" : " DISABLED",
+                val, mask,
+                pci_config_addr.bits.busnum,
+                pci_config_addr.bits.devnum,
+                pci_config_addr.bits.funcnum,
+                pci_config_addr.bits.offset);
+        return true;
+}
+
+static void pci_addr_ioread(u16 port, u32 mask, u32 *val)
+{
+        ioread(port - PCI_CONFIG_ADDR, pci_config_addr.val, mask, val);
+}
+
+/* Is this accessing the PCI config data port?. */
+static bool is_pci_data_port(u16 port)
+{
+        return port >= PCI_CONFIG_DATA && port < PCI_CONFIG_DATA + 4;
+}
+
+static void emulate_mmio_write(struct device *d, u32 off, u32 val, u32 mask);
+
+static bool pci_data_iowrite(u16 port, u32 mask, u32 val)
+{
+        u32 reg, portoff;
+        struct device *d = dev_and_reg(&reg);
+
+        /* Complain if they don't belong to a device. */
+        if (!d)
+                return false;
+
+        /* They can do 1 byte writes, etc. */
+        portoff = port - PCI_CONFIG_DATA;
+
+        /*
+         * PCI uses a weird way to determine the BAR size: the OS
+         * writes all 1's, and sees which ones stick.
+         */
+        if (&d->config_words[reg] == &d->config.bar[0]) {
+                int i;
+
+                iowrite(portoff, val, mask, &d->config.bar[0]);
+                for (i = 0; (1 << i) < d->mmio_size; i++)
+                        d->config.bar[0] &= ~(1 << i);
+                return true;
+        } else if ((&d->config_words[reg] > &d->config.bar[0]
+                    && &d->config_words[reg] <= &d->config.bar[6])
+                   || &d->config_words[reg] == &d->config.expansion_rom_addr) {
+                /* Allow writing to any other BAR, or expansion ROM */
+                iowrite(portoff, val, mask, &d->config_words[reg]);
+                return true;
+                /* We let them overide latency timer and cacheline size */
+        } else if (&d->config_words[reg] == (void *)&d->config.cacheline_size) {
+                /* Only let them change the first two fields. */
+                if (mask == 0xFFFFFFFF)
+                        mask = 0xFFFF;
+                iowrite(portoff, val, mask, &d->config_words[reg]);
+                return true;
+        } else if (&d->config_words[reg] == (void *)&d->config.command
+                   && mask == 0xFFFF) {
+                /* Ignore command writes. */
+                return true;
+        } else if (&d->config_words[reg]
+                   == (void *)&d->config.cfg_access.cap.bar
+                   || &d->config_words[reg]
+                   == &d->config.cfg_access.cap.length
+                   || &d->config_words[reg]
+                   == &d->config.cfg_access.cap.offset) {
+
+                /*
+                 * The VIRTIO_PCI_CAP_PCI_CFG capability
+                 * provides a backdoor to access the MMIO
+                 * regions without mapping them.  Weird, but
+                 * useful.
+                 */
+                iowrite(portoff, val, mask, &d->config_words[reg]);
+                return true;
+        } else if (&d->config_words[reg] == &d->config.cfg_access.pci_cfg_data) {
+                u32 write_mask;
+
+                /*
+                 * 4.1.4.7.1:
+                 *
+                 *  Upon detecting driver write access to pci_cfg_data, the
+                 *  device MUST execute a write access at offset cap.offset at
+                 *  BAR selected by cap.bar using the first cap.length bytes
+                 *  from pci_cfg_data.
+                 */
+
+                /* Must be bar 0 */
+                if (!valid_bar_access(d, &d->config.cfg_access))
+                        return false;
+
+                iowrite(portoff, val, mask, &d->config.cfg_access.pci_cfg_data);
+
+                /*
+                 * Now emulate a write.  The mask we use is set by
+                 * len, *not* this write!
+                 */
+                write_mask = (1ULL<<(8*d->config.cfg_access.cap.length)) - 1;
+                verbose("Window writing %#x/%#x to bar %u, offset %u len %u\n",
+                        d->config.cfg_access.pci_cfg_data, write_mask,
+                        d->config.cfg_access.cap.bar,
+                        d->config.cfg_access.cap.offset,
+                        d->config.cfg_access.cap.length);
+
+                emulate_mmio_write(d, d->config.cfg_access.cap.offset,
+                                   d->config.cfg_access.pci_cfg_data,
+                                   write_mask);
+                return true;
+        }
+
+        /*
+         * 4.1.4.1:
+         *
+         *  The driver MUST NOT write into any field of the capability
+         *  structure, with the exception of those with cap_type
+         *  VIRTIO_PCI_CAP_PCI_CFG...
+         */
+        return false;
+}
+
+static u32 emulate_mmio_read(struct device *d, u32 off, u32 mask);
+
+static void pci_data_ioread(u16 port, u32 mask, u32 *val)
+{
+        u32 reg;
+        struct device *d = dev_and_reg(&reg);
+
+        if (!d)
+                return;
+
+        /* Read through the PCI MMIO access window is special */
+        if (&d->config_words[reg] == &d->config.cfg_access.pci_cfg_data) {
+                u32 read_mask;
+
+                /*
+                 * 4.1.4.7.1:
+                 *
+                 *  Upon detecting driver read access to pci_cfg_data, the
+                 *  device MUST execute a read access of length cap.length at
+                 *  offset cap.offset at BAR selected by cap.bar and store the
+                 *  first cap.length bytes in pci_cfg_data.
+                 */
+                /* Must be bar 0 */
+                if (!valid_bar_access(d, &d->config.cfg_access))
+                        bad_driver(d,
+                             "Invalid cfg_access to bar%u, offset %u len %u",
+                             d->config.cfg_access.cap.bar,
+                             d->config.cfg_access.cap.offset,
+                             d->config.cfg_access.cap.length);
+
+                /*
+                 * Read into the window.  The mask we use is set by
+                 * len, *not* this read!
+                 */
+                read_mask = (1ULL<<(8*d->config.cfg_access.cap.length))-1;
+                d->config.cfg_access.pci_cfg_data
+                        = emulate_mmio_read(d,
+                                            d->config.cfg_access.cap.offset,
+                                            read_mask);
+                verbose("Window read %#x/%#x from bar %u, offset %u len %u\n",
+                        d->config.cfg_access.pci_cfg_data, read_mask,
+                        d->config.cfg_access.cap.bar,
+                        d->config.cfg_access.cap.offset,
+                        d->config.cfg_access.cap.length);
+        }
+        ioread(port - PCI_CONFIG_DATA, d->config_words[reg], mask, val);
+}
+
 /*L:216
- * This actually creates the thread which services the virtqueue for a device.
+ * This is where we emulate a handful of Guest instructions.  It's ugly
+ * and we used to do it in the kernel but it grew over time.
+ */
+
+/*
+ * We use the ptrace syscall's pt_regs struct to talk about registers
+ * to lguest: these macros convert the names to the offsets.
+ */
+#define getreg(name) getreg_off(offsetof(struct user_regs_struct, name))
+#define setreg(name, val) \
+        setreg_off(offsetof(struct user_regs_struct, name), (val))
+
+static u32 getreg_off(size_t offset)
+{
+        u32 r;
+        unsigned long args[] = { LHREQ_GETREG, offset };
+
+        if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0)
+                err(1, "Getting register %u", offset);
+        if (pread(lguest_fd, &r, sizeof(r), cpu_id) != sizeof(r))
+                err(1, "Reading register %u", offset);
+
+        return r;
+}
+
+static void setreg_off(size_t offset, u32 val)
+{
+        unsigned long args[] = { LHREQ_SETREG, offset, val };
+
+        if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0)
+                err(1, "Setting register %u", offset);
+}
+
+/* Get register by instruction encoding */
+static u32 getreg_num(unsigned regnum, u32 mask)
+{
+        /* 8 bit ops use regnums 4-7 for high parts of word */
+        if (mask == 0xFF && (regnum & 0x4))
+                return getreg_num(regnum & 0x3, 0xFFFF) >> 8;
+
+        switch (regnum) {
+        case 0: return getreg(eax) & mask;
+        case 1: return getreg(ecx) & mask;
+        case 2: return getreg(edx) & mask;
+        case 3: return getreg(ebx) & mask;
+        case 4: return getreg(esp) & mask;
+        case 5: return getreg(ebp) & mask;
+        case 6: return getreg(esi) & mask;
+        case 7: return getreg(edi) & mask;
+        }
+        abort();
+}
+
+/* Set register by instruction encoding */
+static void setreg_num(unsigned regnum, u32 val, u32 mask)
+{
+        /* Don't try to set bits out of range */
+        assert(~(val & ~mask));
+
+        /* 8 bit ops use regnums 4-7 for high parts of word */
+        if (mask == 0xFF && (regnum & 0x4)) {
+                /* Construct the 16 bits we want. */
+                val = (val << 8) | getreg_num(regnum & 0x3, 0xFF);
+                setreg_num(regnum & 0x3, val, 0xFFFF);
+                return;
+        }
+
+        switch (regnum) {
+        case 0: setreg(eax, val | (getreg(eax) & ~mask)); return;
+        case 1: setreg(ecx, val | (getreg(ecx) & ~mask)); return;
+        case 2: setreg(edx, val | (getreg(edx) & ~mask)); return;
+        case 3: setreg(ebx, val | (getreg(ebx) & ~mask)); return;
+        case 4: setreg(esp, val | (getreg(esp) & ~mask)); return;
+        case 5: setreg(ebp, val | (getreg(ebp) & ~mask)); return;
+        case 6: setreg(esi, val | (getreg(esi) & ~mask)); return;
+        case 7: setreg(edi, val | (getreg(edi) & ~mask)); return;
+        }
+        abort();
+}
+
+/* Get bytes of displacement appended to instruction, from r/m encoding */
+static u32 insn_displacement_len(u8 mod_reg_rm)
+{
+        /* Switch on the mod bits */
+        switch (mod_reg_rm >> 6) {
+        case 0:
+                /* If mod == 0, and r/m == 101, 16-bit displacement follows */
+                if ((mod_reg_rm & 0x7) == 0x5)
+                        return 2;
+                /* Normally, mod == 0 means no literal displacement */
+                return 0;
+        case 1:
+                /* One byte displacement */
+                return 1;
+        case 2:
+                /* Four byte displacement */
+                return 4;
+        case 3:
+                /* Register mode */
+                return 0;
+        }
+        abort();
+}
+
+static void emulate_insn(const u8 insn[])
+{
+        unsigned long args[] = { LHREQ_TRAP, 13 };
+        unsigned int insnlen = 0, in = 0, small_operand = 0, byte_access;
+        unsigned int eax, port, mask;
+        /*
+         * Default is to return all-ones on IO port reads, which traditionally
+         * means "there's nothing there".
+         */
+        u32 val = 0xFFFFFFFF;
+
+        /*
+         * This must be the Guest kernel trying to do something, not userspace!
+         * The bottom two bits of the CS segment register are the privilege
+         * level.
+         */
+        if ((getreg(xcs) & 3) != 0x1)
+                goto no_emulate;
+
+        /* Decoding x86 instructions is icky. */
+
+        /*
+         * Around 2.6.33, the kernel started using an emulation for the
+         * cmpxchg8b instruction in early boot on many configurations.  This
+         * code isn't paravirtualized, and it tries to disable interrupts.
+         * Ignore it, which will Mostly Work.
+         */
+        if (insn[insnlen] == 0xfa) {
+                /* "cli", or Clear Interrupt Enable instruction.  Skip it. */
+                insnlen = 1;
+                goto skip_insn;
+        }
+
+        /*
+         * 0x66 is an "operand prefix".  It means a 16, not 32 bit in/out.
+         */
+        if (insn[insnlen] == 0x66) {
+                small_operand = 1;
+                /* The instruction is 1 byte so far, read the next byte. */
+                insnlen = 1;
+        }
+
+        /* If the lower bit isn't set, it's a single byte access */
+        byte_access = !(insn[insnlen] & 1);
+
+        /*
+         * Now we can ignore the lower bit and decode the 4 opcodes
+         * we need to emulate.
+         */
+        switch (insn[insnlen] & 0xFE) {
+        case 0xE4: /* in     <next byte>,%al */
+                port = insn[insnlen+1];
+                insnlen += 2;
+                in = 1;
+                break;
+        case 0xEC: /* in     (%dx),%al */
+                port = getreg(edx) & 0xFFFF;
+                insnlen += 1;
+                in = 1;
+                break;
+        case 0xE6: /* out    %al,<next byte> */
+                port = insn[insnlen+1];
+                insnlen += 2;
+                break;
+        case 0xEE: /* out    %al,(%dx) */
+                port = getreg(edx) & 0xFFFF;
+                insnlen += 1;
+                break;
+        default:
+                /* OK, we don't know what this is, can't emulate. */
+                goto no_emulate;
+        }
+
+        /* Set a mask of the 1, 2 or 4 bytes, depending on size of IO */
+        if (byte_access)
+                mask = 0xFF;
+        else if (small_operand)
+                mask = 0xFFFF;
+        else
+                mask = 0xFFFFFFFF;
+
+        /*
+         * If it was an "IN" instruction, they expect the result to be read
+         * into %eax, so we change %eax.
+         */
+        eax = getreg(eax);
+
+        if (in) {
+                /* This is the PS/2 keyboard status; 1 means ready for output */
+                if (port == 0x64)
+                        val = 1;
+                else if (is_pci_addr_port(port))
+                        pci_addr_ioread(port, mask, &val);
+                else if (is_pci_data_port(port))
+                        pci_data_ioread(port, mask, &val);
+
+                /* Clear the bits we're about to read */
+                eax &= ~mask;
+                /* Copy bits in from val. */
+                eax |= val & mask;
+                /* Now update the register. */
+                setreg(eax, eax);
+        } else {
+                if (is_pci_addr_port(port)) {
+                        if (!pci_addr_iowrite(port, mask, eax))
+                                goto bad_io;
+                } else if (is_pci_data_port(port)) {
+                        if (!pci_data_iowrite(port, mask, eax))
+                                goto bad_io;
+                }
+                /* There are many other ports, eg. CMOS clock, serial
+                 * and parallel ports, so we ignore them all. */
+        }
+
+        verbose("IO %s of %x to %u: %#08x\n",
+                in ? "IN" : "OUT", mask, port, eax);
+skip_insn:
+        /* Finally, we've "done" the instruction, so move past it. */
+        setreg(eip, getreg(eip) + insnlen);
+        return;
+
+bad_io:
+        warnx("Attempt to %s port %u (%#x mask)",
+              in ? "read from" : "write to", port, mask);
+
+no_emulate:
+        /* Inject trap into Guest. */
+        if (write(lguest_fd, args, sizeof(args)) < 0)
+                err(1, "Reinjecting trap 13 for fault at %#x", getreg(eip));
+}
+
+static struct device *find_mmio_region(unsigned long paddr, u32 *off)
+{
+        unsigned int i;
+
+        for (i = 1; i < MAX_PCI_DEVICES; i++) {
+                struct device *d = devices.pci[i];
+
+                if (!d)
+                        continue;
+                if (paddr < d->mmio_addr)
+                        continue;
+                if (paddr >= d->mmio_addr + d->mmio_size)
+                        continue;
+                *off = paddr - d->mmio_addr;
+                return d;
+        }
+        return NULL;
+}
+
+/* FIXME: Use vq array. */
+static struct virtqueue *vq_by_num(struct device *d, u32 num)
+{
+        struct virtqueue *vq = d->vq;
+
+        while (num-- && vq)
+                vq = vq->next;
+
+        return vq;
+}
+
+static void save_vq_config(const struct virtio_pci_common_cfg *cfg,
+                           struct virtqueue *vq)
+{
+        vq->pci_config = *cfg;
+}
+
+static void restore_vq_config(struct virtio_pci_common_cfg *cfg,
+                              struct virtqueue *vq)
+{
+        /* Only restore the per-vq part */
+        size_t off = offsetof(struct virtio_pci_common_cfg, queue_size);
+
+        memcpy((void *)cfg + off, (void *)&vq->pci_config + off,
+               sizeof(*cfg) - off);
+}
+
+/*
+ * 4.1.4.3.2:
+ *
+ *  The driver MUST configure the other virtqueue fields before
+ *  enabling the virtqueue with queue_enable.
+ *
+ * When they enable the virtqueue, we check that their setup is valid.
  */
-static void create_thread(struct virtqueue *vq)
+static void check_virtqueue(struct device *d, struct virtqueue *vq)
+{
+        /* Because lguest is 32 bit, all the descriptor high bits must be 0 */
+        if (vq->pci_config.queue_desc_hi
+            || vq->pci_config.queue_avail_hi
+            || vq->pci_config.queue_used_hi)
+                bad_driver_vq(vq, "invalid 64-bit queue address");
+
+        /*
+         * 2.4.1:
+         *
+         *  The driver MUST ensure that the physical address of the first byte
+         *  of each virtqueue part is a multiple of the specified alignment
+         *  value in the above table.
+         */
+        if (vq->pci_config.queue_desc_lo % 16
+            || vq->pci_config.queue_avail_lo % 2
+            || vq->pci_config.queue_used_lo % 4)
+                bad_driver_vq(vq, "invalid alignment in queue addresses");
+
+        /* Initialize the virtqueue and check they're all in range. */
+        vq->vring.num = vq->pci_config.queue_size;
+        vq->vring.desc = check_pointer(vq->dev,
+                                       vq->pci_config.queue_desc_lo,
+                                       sizeof(*vq->vring.desc) * vq->vring.num);
+        vq->vring.avail = check_pointer(vq->dev,
+                                        vq->pci_config.queue_avail_lo,
+                                        sizeof(*vq->vring.avail)
+                                        + (sizeof(vq->vring.avail->ring[0])
+                                           * vq->vring.num));
+        vq->vring.used = check_pointer(vq->dev,
+                                       vq->pci_config.queue_used_lo,
+                                       sizeof(*vq->vring.used)
+                                       + (sizeof(vq->vring.used->ring[0])
+                                          * vq->vring.num));
+
+        /*
+         * 2.4.9.1:
+         *
+         *   The driver MUST initialize flags in the used ring to 0
+         *   when allocating the used ring.
+         */
+        if (vq->vring.used->flags != 0)
+                bad_driver_vq(vq, "invalid initial used.flags %#x",
+                              vq->vring.used->flags);
+}
+
+static void start_virtqueue(struct virtqueue *vq)
 {
         /*
          * Create stack for thread.  Since the stack grows upwards, we point
          * the stack pointer to the end of this region.
          */
         char *stack = malloc(32768);
-        unsigned long args[] = { LHREQ_EVENTFD,
-                                 vq->config.pfn*getpagesize(), 0 };
 
         /* Create a zero-initialized eventfd. */
         vq->eventfd = eventfd(0, 0);
         if (vq->eventfd < 0)
                 err(1, "Creating eventfd");
-        args[2] = vq->eventfd;
-
-        /*
-         * Attach an eventfd to this virtqueue: it will go off when the Guest
-         * does an LHCALL_NOTIFY for this vq.
-         */
-        if (write(lguest_fd, &args, sizeof(args)) != 0)
-                err(1, "Attaching eventfd");
 
         /*
          * CLONE_VM: because it has to access the Guest memory, and SIGCHLD so
@@ -1048,167 +1859,531 @@ static void create_thread(struct virtqueue *vq)
         vq->thread = clone(do_thread, stack + 32768, CLONE_VM | SIGCHLD, vq);
         if (vq->thread == (pid_t)-1)
                 err(1, "Creating clone");
-
-        /* We close our local copy now the child has it. */
-        close(vq->eventfd);
 }
 
-static void start_device(struct device *dev)
+static void start_virtqueues(struct device *d)
 {
-        unsigned int i;
         struct virtqueue *vq;
 
-        verbose("Device %s OK: offered", dev->name);
-        for (i = 0; i < dev->feature_len; i++)
-                verbose(" %02x", get_feature_bits(dev)[i]);
-        verbose(", accepted");
-        for (i = 0; i < dev->feature_len; i++)
-                verbose(" %02x", get_feature_bits(dev)
-                        [dev->feature_len+i]);
-
-        for (vq = dev->vq; vq; vq = vq->next) {
-                if (vq->service)
-                        create_thread(vq);
+        for (vq = d->vq; vq; vq = vq->next) {
+                if (vq->pci_config.queue_enable)
+                        start_virtqueue(vq);
         }
-        dev->running = true;
 }
 
-static void cleanup_devices(void)
+static void emulate_mmio_write(struct device *d, u32 off, u32 val, u32 mask)
 {
-        struct device *dev;
+        struct virtqueue *vq;
 
-        for (dev = devices.dev; dev; dev = dev->next)
-                reset_device(dev);
+        switch (off) {
+        case offsetof(struct virtio_pci_mmio, cfg.device_feature_select):
+                /*
+                 * 4.1.4.3.1:
+                 *
+                 * The device MUST present the feature bits it is offering in
+                 * device_feature, starting at bit device_feature_select ∗ 32
+                 * for any device_feature_select written by the driver
+                 */
+                if (val == 0)
+                        d->mmio->cfg.device_feature = d->features;
+                else if (val == 1)
+                        d->mmio->cfg.device_feature = (d->features >> 32);
+                else
+                        d->mmio->cfg.device_feature = 0;
+                goto feature_write_through32;
+        case offsetof(struct virtio_pci_mmio, cfg.guest_feature_select):
+                if (val > 1)
+                        bad_driver(d, "Unexpected driver select %u", val);
+                goto feature_write_through32;
+        case offsetof(struct virtio_pci_mmio, cfg.guest_feature):
+                if (d->mmio->cfg.guest_feature_select == 0) {
+                        d->features_accepted &= ~((u64)0xFFFFFFFF);
+                        d->features_accepted |= val;
+                } else {
+                        assert(d->mmio->cfg.guest_feature_select == 1);
+                        d->features_accepted &= 0xFFFFFFFF;
+                        d->features_accepted |= ((u64)val) << 32;
+                }
+                /*
+                 * 2.2.1:
+                 *
+                 *   The driver MUST NOT accept a feature which the device did
+                 *   not offer
+                 */
+                if (d->features_accepted & ~d->features)
+                        bad_driver(d, "over-accepted features %#llx of %#llx",
+                                   d->features_accepted, d->features);
+                goto feature_write_through32;
+        case offsetof(struct virtio_pci_mmio, cfg.device_status): {
+                u8 prev;
+
+                verbose("%s: device status -> %#x\n", d->name, val);
+                /*
+                 * 4.1.4.3.1:
+                 * 
+                 *  The device MUST reset when 0 is written to device_status,
+                 *  and present a 0 in device_status once that is done.
+                 */
+                if (val == 0) {
+                        reset_device(d);
+                        goto write_through8;
+                }
 
-        /* If we saved off the original terminal settings, restore them now. */
-        if (orig_term.c_lflag & (ISIG|ICANON|ECHO))
-                tcsetattr(STDIN_FILENO, TCSANOW, &orig_term);
-}
+                /* 2.1.1: The driver MUST NOT clear a device status bit. */
+                if (d->mmio->cfg.device_status & ~val)
+                        bad_driver(d, "unset of device status bit %#x -> %#x",
+                                   d->mmio->cfg.device_status, val);
 
-/* When the Guest tells us they updated the status field, we handle it. */
-static void update_device_status(struct device *dev)
-{
-        /* A zero status is a reset, otherwise it's a set of flags. */
-        if (dev->desc->status == 0)
-                reset_device(dev);
-        else if (dev->desc->status & VIRTIO_CONFIG_S_FAILED) {
-                warnx("Device %s configuration FAILED", dev->name);
-                if (dev->running)
-                        reset_device(dev);
-        } else {
-                if (dev->running)
-                        err(1, "Device %s features finalized twice", dev->name);
-                start_device(dev);
+                /*
+                 * 2.1.2:
+                 *
+                 *  The device MUST NOT consume buffers or notify the driver
+                 *  before DRIVER_OK.
+                 */
+                if (val & VIRTIO_CONFIG_S_DRIVER_OK
+                    && !(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER_OK))
+                        start_virtqueues(d);
+
+                /*
+                 * 3.1.1:
+                 *
+                 *   The driver MUST follow this sequence to initialize a device:
+                 *   - Reset the device.
+                 *   - Set the ACKNOWLEDGE status bit: the guest OS has
+                 *     notice the device.
+                 *   - Set the DRIVER status bit: the guest OS knows how
+                 *     to drive the device.
+                 *   - Read device feature bits, and write the subset
+                 *     of feature bits understood by the OS and driver
+                 *     to the device. During this step the driver MAY
+                 *     read (but MUST NOT write) the device-specific
+                 *     configuration fields to check that it can
+                 *     support the device before accepting it.
+                 *   - Set the FEATURES_OK status bit.  The driver
+                 *     MUST not accept new feature bits after this
+                 *     step.
+                 *   - Re-read device status to ensure the FEATURES_OK
+                 *     bit is still set: otherwise, the device does
+                 *     not support our subset of features and the
+                 *     device is unusable.
+                 *   - Perform device-specific setup, including
+                 *     discovery of virtqueues for the device,
+                 *     optional per-bus setup, reading and possibly
+                 *     writing the device’s virtio configuration
+                 *     space, and population of virtqueues.
+                 *   - Set the DRIVER_OK status bit. At this point the
+                 *     device is “live”.
+                 */
+                prev = 0;
+                switch (val & ~d->mmio->cfg.device_status) {
+                case VIRTIO_CONFIG_S_DRIVER_OK:
+                        prev |= VIRTIO_CONFIG_S_FEATURES_OK; /* fall thru */
+                case VIRTIO_CONFIG_S_FEATURES_OK:
+                        prev |= VIRTIO_CONFIG_S_DRIVER; /* fall thru */
+                case VIRTIO_CONFIG_S_DRIVER:
+                        prev |= VIRTIO_CONFIG_S_ACKNOWLEDGE; /* fall thru */
+                case VIRTIO_CONFIG_S_ACKNOWLEDGE:
+                        break;
+                default:
+                        bad_driver(d, "unknown device status bit %#x -> %#x",
+                                   d->mmio->cfg.device_status, val);
+                }
+                if (d->mmio->cfg.device_status != prev)
+                        bad_driver(d, "unexpected status transition %#x -> %#x",
+                                   d->mmio->cfg.device_status, val);
+
+                /* If they just wrote FEATURES_OK, we make sure they read */
+                switch (val & ~d->mmio->cfg.device_status) {
+                case VIRTIO_CONFIG_S_FEATURES_OK:
+                        d->wrote_features_ok = true;
+                        break;
+                case VIRTIO_CONFIG_S_DRIVER_OK:
+                        if (d->wrote_features_ok)
+                                bad_driver(d, "did not re-read FEATURES_OK");
+                        break;
+                }
+                goto write_through8;
         }
-}
+        case offsetof(struct virtio_pci_mmio, cfg.queue_select):
+                vq = vq_by_num(d, val);
+                /*
+                 * 4.1.4.3.1:
+                 *
+                 *  The device MUST present a 0 in queue_size if the virtqueue
+                 *  corresponding to the current queue_select is unavailable.
+                 */
+                if (!vq) {
+                        d->mmio->cfg.queue_size = 0;
+                        goto write_through16;
+                }
+                /* Save registers for old vq, if it was a valid vq */
+                if (d->mmio->cfg.queue_size)
+                        save_vq_config(&d->mmio->cfg,
+                                       vq_by_num(d, d->mmio->cfg.queue_select));
+                /* Restore the registers for the queue they asked for */
+                restore_vq_config(&d->mmio->cfg, vq);
+                goto write_through16;
+        case offsetof(struct virtio_pci_mmio, cfg.queue_size):
+                /*
+                 * 4.1.4.3.2:
+                 *
+                 *  The driver MUST NOT write a value which is not a power of 2
+                 *  to queue_size.
+                 */
+                if (val & (val-1))
+                        bad_driver(d, "invalid queue size %u", val);
+                if (d->mmio->cfg.queue_enable)
+                        bad_driver(d, "changing queue size on live device");
+                goto write_through16;
+        case offsetof(struct virtio_pci_mmio, cfg.queue_msix_vector):
+                bad_driver(d, "attempt to set MSIX vector to %u", val);
+        case offsetof(struct virtio_pci_mmio, cfg.queue_enable): {
+                struct virtqueue *vq = vq_by_num(d, d->mmio->cfg.queue_select);
 
-/*L:215
- * This is the generic routine we call when the Guest uses LHCALL_NOTIFY.  In
- * particular, it's used to notify us of device status changes during boot.
- */
-static void handle_output(unsigned long addr)
-{
-        struct device *i;
+                /*
+                 * 4.1.4.3.2:
+                 *
+                 *  The driver MUST NOT write a 0 to queue_enable.
+                 */
+                if (val != 1)
+                        bad_driver(d, "setting queue_enable to %u", val);
 
-        /* Check each device. */
-        for (i = devices.dev; i; i = i->next) {
-                struct virtqueue *vq;
+                /*
+                 * 3.1.1:
+                 *
+                 *  7. Perform device-specific setup, including discovery of
+                 *     virtqueues for the device, optional per-bus setup,
+                 *     reading and possibly writing the device’s virtio
+                 *     configuration space, and population of virtqueues.
+                 *  8. Set the DRIVER_OK status bit.
+                 *
+                 * All our devices require all virtqueues to be enabled, so
+                 * they should have done that before setting DRIVER_OK.
+                 */
+                if (d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER_OK)
+                        bad_driver(d, "enabling vq after DRIVER_OK");
 
+                d->mmio->cfg.queue_enable = val;
+                save_vq_config(&d->mmio->cfg, vq);
+                check_virtqueue(d, vq);
+                goto write_through16;
+        }
+        case offsetof(struct virtio_pci_mmio, cfg.queue_notify_off):
+                bad_driver(d, "attempt to write to queue_notify_off");
+        case offsetof(struct virtio_pci_mmio, cfg.queue_desc_lo):
+        case offsetof(struct virtio_pci_mmio, cfg.queue_desc_hi):
+        case offsetof(struct virtio_pci_mmio, cfg.queue_avail_lo):
+        case offsetof(struct virtio_pci_mmio, cfg.queue_avail_hi):
+        case offsetof(struct virtio_pci_mmio, cfg.queue_used_lo):
+        case offsetof(struct virtio_pci_mmio, cfg.queue_used_hi):
                 /*
-                 * Notifications to device descriptors mean they updated the
-                 * device status.
+                 * 4.1.4.3.2:
+                 *
+                 *  The driver MUST configure the other virtqueue fields before
+                 *  enabling the virtqueue with queue_enable.
                  */
-                if (from_guest_phys(addr) == i->desc) {
-                        update_device_status(i);
-                        return;
-                }
+                if (d->mmio->cfg.queue_enable)
+                        bad_driver(d, "changing queue on live device");
+
+                /*
+                 * 3.1.1:
+                 *
+                 *  The driver MUST follow this sequence to initialize a device:
+                 *...
+                 *  5. Set the FEATURES_OK status bit. The driver MUST not
+                 *  accept new feature bits after this step.
+                 */
+                if (!(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_FEATURES_OK))
+                        bad_driver(d, "setting up vq before FEATURES_OK");
 
-                /* Devices should not be used before features are finalized. */
-                for (vq = i->vq; vq; vq = vq->next) {
-                        if (addr != vq->config.pfn*getpagesize())
-                                continue;
-                        errx(1, "Notification on %s before setup!", i->name);
+                /*
+                 *  6. Re-read device status to ensure the FEATURES_OK bit is
+                 *     still set...
+                 */
+                if (d->wrote_features_ok)
+                        bad_driver(d, "didn't re-read FEATURES_OK before setup");
+
+                goto write_through32;
+        case offsetof(struct virtio_pci_mmio, notify):
+                vq = vq_by_num(d, val);
+                if (!vq)
+                        bad_driver(d, "Invalid vq notification on %u", val);
+                /* Notify the process handling this vq by adding 1 to eventfd */
+                write(vq->eventfd, "\1\0\0\0\0\0\0\0", 8);
+                goto write_through16;
+        case offsetof(struct virtio_pci_mmio, isr):
+                bad_driver(d, "Unexpected write to isr");
+        /* Weird corner case: write to emerg_wr of console */
+        case sizeof(struct virtio_pci_mmio)
+                + offsetof(struct virtio_console_config, emerg_wr):
+                if (strcmp(d->name, "console") == 0) {
+                        char c = val;
+                        write(STDOUT_FILENO, &c, 1);
+                        goto write_through32;
                 }
+                /* Fall through... */
+        default:
+                /*
+                 * 4.1.4.3.2:
+                 *
+                 *   The driver MUST NOT write to device_feature, num_queues,
+                 *   config_generation or queue_notify_off.
+                 */
+                bad_driver(d, "Unexpected write to offset %u", off);
         }
 
+feature_write_through32:
         /*
-         * Early console write is done using notify on a nul-terminated string
-         * in Guest memory.  It's also great for hacking debugging messages
-         * into a Guest.
+         * 3.1.1:
+         *
+         *   The driver MUST follow this sequence to initialize a device:
+         *...
+         *   - Set the DRIVER status bit: the guest OS knows how
+         *     to drive the device.
+         *   - Read device feature bits, and write the subset
+         *     of feature bits understood by the OS and driver
+         *     to the device.
+         *...
+         *   - Set the FEATURES_OK status bit. The driver MUST not
+         *     accept new feature bits after this step.
          */
-        if (addr >= guest_limit)
-                errx(1, "Bad NOTIFY %#lx", addr);
+        if (!(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER))
+                bad_driver(d, "feature write before VIRTIO_CONFIG_S_DRIVER");
+        if (d->mmio->cfg.device_status & VIRTIO_CONFIG_S_FEATURES_OK)
+                bad_driver(d, "feature write after VIRTIO_CONFIG_S_FEATURES_OK");
 
-        write(STDOUT_FILENO, from_guest_phys(addr),
-              strnlen(from_guest_phys(addr), guest_limit - addr));
+        /*
+         * 4.1.3.1:
+         *
+         *  The driver MUST access each field using the “natural” access
+         *  method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses for
+         *  16-bit fields and 8-bit accesses for 8-bit fields.
+         */
+write_through32:
+        if (mask != 0xFFFFFFFF) {
+                bad_driver(d, "non-32-bit write to offset %u (%#x)",
+                           off, getreg(eip));
+                return;
+        }
+        memcpy((char *)d->mmio + off, &val, 4);
+        return;
+
+write_through16:
+        if (mask != 0xFFFF)
+                bad_driver(d, "non-16-bit write to offset %u (%#x)",
+                           off, getreg(eip));
+        memcpy((char *)d->mmio + off, &val, 2);
+        return;
+
+write_through8:
+        if (mask != 0xFF)
+                bad_driver(d, "non-8-bit write to offset %u (%#x)",
+                           off, getreg(eip));
+        memcpy((char *)d->mmio + off, &val, 1);
+        return;
 }
 
-/*L:190
- * Device Setup
- *
- * All devices need a descriptor so the Guest knows it exists, and a "struct
- * device" so the Launcher can keep track of it.  We have common helper
- * routines to allocate and manage them.
- */
-
-/*
- * The layout of the device page is a "struct lguest_device_desc" followed by a
- * number of virtqueue descriptors, then two sets of feature bits, then an
- * array of configuration bytes.  This routine returns the configuration
- * pointer.
- */
-static u8 *device_config(const struct device *dev)
+static u32 emulate_mmio_read(struct device *d, u32 off, u32 mask)
 {
-        return (void *)(dev->desc + 1)
-                + dev->num_vq * sizeof(struct lguest_vqconfig)
-                + dev->feature_len * 2;
+        u8 isr;
+        u32 val = 0;
+
+        switch (off) {
+        case offsetof(struct virtio_pci_mmio, cfg.device_feature_select):
+        case offsetof(struct virtio_pci_mmio, cfg.device_feature):
+        case offsetof(struct virtio_pci_mmio, cfg.guest_feature_select):
+        case offsetof(struct virtio_pci_mmio, cfg.guest_feature):
+                /*
+                 * 3.1.1:
+                 *
+                 *   The driver MUST follow this sequence to initialize a device:
+                 *...
+                 *   - Set the DRIVER status bit: the guest OS knows how
+                 *     to drive the device.
+                 *   - Read device feature bits, and write the subset
+                 *     of feature bits understood by the OS and driver
+                 *     to the device.
+                 */
+                if (!(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER))
+                        bad_driver(d,
+                                   "feature read before VIRTIO_CONFIG_S_DRIVER");
+                goto read_through32;
+        case offsetof(struct virtio_pci_mmio, cfg.msix_config):
+                bad_driver(d, "read of msix_config");
+        case offsetof(struct virtio_pci_mmio, cfg.num_queues):
+                goto read_through16;
+        case offsetof(struct virtio_pci_mmio, cfg.device_status):
+                /* As they did read, any write of FEATURES_OK is now fine. */
+                d->wrote_features_ok = false;
+                goto read_through8;
+        case offsetof(struct virtio_pci_mmio, cfg.config_generation):
+                /*
+                 * 4.1.4.3.1:
+                 *
+                 *  The device MUST present a changed config_generation after
+                 *  the driver has read a device-specific configuration value
+                 *  which has changed since any part of the device-specific
+                 *  configuration was last read.
+                 *
+                 * This is simple: none of our devices change config, so this
+                 * is always 0.
+                 */
+                goto read_through8;
+        case offsetof(struct virtio_pci_mmio, notify):
+                /*
+                 * 3.1.1:
+                 *
+                 *   The driver MUST NOT notify the device before setting
+                 *   DRIVER_OK.
+                 */
+                if (!(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER_OK))
+                        bad_driver(d, "notify before VIRTIO_CONFIG_S_DRIVER_OK");
+                goto read_through16;
+        case offsetof(struct virtio_pci_mmio, isr):
+                if (mask != 0xFF)
+                        bad_driver(d, "non-8-bit read from offset %u (%#x)",
+                                   off, getreg(eip));
+                isr = d->mmio->isr;
+                /*
+                 * 4.1.4.5.1:
+                 *
+                 *  The device MUST reset ISR status to 0 on driver read. 
+                 */
+                d->mmio->isr = 0;
+                return isr;
+        case offsetof(struct virtio_pci_mmio, padding):
+                bad_driver(d, "read from padding (%#x)", getreg(eip));
+        default:
+                /* Read from device config space, beware unaligned overflow */
+                if (off > d->mmio_size - 4)
+                        bad_driver(d, "read past end (%#x)", getreg(eip));
+
+                /*
+                 * 3.1.1:
+                 *  The driver MUST follow this sequence to initialize a device:
+                 *...
+                 *  3. Set the DRIVER status bit: the guest OS knows how to
+                 *  drive the device.
+                 *  4. Read device feature bits, and write the subset of
+                 *  feature bits understood by the OS and driver to the
+                 *  device. During this step the driver MAY read (but MUST NOT
+                 *  write) the device-specific configuration fields to check
+                 *  that it can support the device before accepting it.
+                 */
+                if (!(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER))
+                        bad_driver(d,
+                                   "config read before VIRTIO_CONFIG_S_DRIVER");
+
+                if (mask == 0xFFFFFFFF)
+                        goto read_through32;
+                else if (mask == 0xFFFF)
+                        goto read_through16;
+                else
+                        goto read_through8;
+        }
+
+        /*
+         * 4.1.3.1:
+         *
+         *  The driver MUST access each field using the “natural” access
+         *  method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses for
+         *  16-bit fields and 8-bit accesses for 8-bit fields.
+         */
+read_through32:
+        if (mask != 0xFFFFFFFF)
+                bad_driver(d, "non-32-bit read to offset %u (%#x)",
+                           off, getreg(eip));
+        memcpy(&val, (char *)d->mmio + off, 4);
+        return val;
+
+read_through16:
+        if (mask != 0xFFFF)
+                bad_driver(d, "non-16-bit read to offset %u (%#x)",
+                           off, getreg(eip));
+        memcpy(&val, (char *)d->mmio + off, 2);
+        return val;
+
+read_through8:
+        if (mask != 0xFF)
+                bad_driver(d, "non-8-bit read to offset %u (%#x)",
+                           off, getreg(eip));
+        memcpy(&val, (char *)d->mmio + off, 1);
+        return val;
 }
 
-/*
- * This routine allocates a new "struct lguest_device_desc" from descriptor
- * table page just above the Guest's normal memory.  It returns a pointer to
- * that descriptor.
- */
-static struct lguest_device_desc *new_dev_desc(u16 type)
+static void emulate_mmio(unsigned long paddr, const u8 *insn)
 {
-        struct lguest_device_desc d = { .type = type };
-        void *p;
+        u32 val, off, mask = 0xFFFFFFFF, insnlen = 0;
+        struct device *d = find_mmio_region(paddr, &off);
+        unsigned long args[] = { LHREQ_TRAP, 14 };
 
-        /* Figure out where the next device config is, based on the last one. */
-        if (devices.lastdev)
-                p = device_config(devices.lastdev)
-                        + devices.lastdev->desc->config_len;
-        else
-                p = devices.descpage;
+        if (!d) {
+                warnx("MMIO touching %#08lx (not a device)", paddr);
+                goto reinject;
+        }
+
+        /* Prefix makes it a 16 bit op */
+        if (insn[0] == 0x66) {
+                mask = 0xFFFF;
+                insnlen++;
+        }
 
-        /* We only have one page for all the descriptors. */
-        if (p + sizeof(d) > (void *)devices.descpage + getpagesize())
-                errx(1, "Too many devices");
+        /* iowrite */
+        if (insn[insnlen] == 0x89) {
+                /* Next byte is r/m byte: bits 3-5 are register. */
+                val = getreg_num((insn[insnlen+1] >> 3) & 0x7, mask);
+                emulate_mmio_write(d, off, val, mask);
+                insnlen += 2 + insn_displacement_len(insn[insnlen+1]);
+        } else if (insn[insnlen] == 0x8b) { /* ioread */
+                /* Next byte is r/m byte: bits 3-5 are register. */
+                val = emulate_mmio_read(d, off, mask);
+                setreg_num((insn[insnlen+1] >> 3) & 0x7, val, mask);
+                insnlen += 2 + insn_displacement_len(insn[insnlen+1]);
+        } else if (insn[0] == 0x88) { /* 8-bit iowrite */
+                mask = 0xff;
+                /* Next byte is r/m byte: bits 3-5 are register. */
+                val = getreg_num((insn[1] >> 3) & 0x7, mask);
+                emulate_mmio_write(d, off, val, mask);
+                insnlen = 2 + insn_displacement_len(insn[1]);
+        } else if (insn[0] == 0x8a) { /* 8-bit ioread */
+                mask = 0xff;
+                val = emulate_mmio_read(d, off, mask);
+                setreg_num((insn[1] >> 3) & 0x7, val, mask);
+                insnlen = 2 + insn_displacement_len(insn[1]);
+        } else {
+                warnx("Unknown MMIO instruction touching %#08lx:"
+                     " %02x %02x %02x %02x at %u",
+                     paddr, insn[0], insn[1], insn[2], insn[3], getreg(eip));
+        reinject:
+                /* Inject trap into Guest. */
+                if (write(lguest_fd, args, sizeof(args)) < 0)
+                        err(1, "Reinjecting trap 14 for fault at %#x",
+                            getreg(eip));
+                return;
+        }
 
-        /* p might not be aligned, so we memcpy in. */
-        return memcpy(p, &d, sizeof(d));
+        /* Finally, we've "done" the instruction, so move past it. */
+        setreg(eip, getreg(eip) + insnlen);
 }
 
-/*
- * Each device descriptor is followed by the description of its virtqueues.  We
- * specify how many descriptors the virtqueue is to have.
+/*L:190
+ * Device Setup
+ *
+ * All devices need a descriptor so the Guest knows it exists, and a "struct
+ * device" so the Launcher can keep track of it.  We have common helper
+ * routines to allocate and manage them.
  */
-static void add_virtqueue(struct device *dev, unsigned int num_descs,
-                          void (*service)(struct virtqueue *))
+static void add_pci_virtqueue(struct device *dev,
+                              void (*service)(struct virtqueue *),
+                              const char *name)
 {
-        unsigned int pages;
         struct virtqueue **i, *vq = malloc(sizeof(*vq));
-        void *p;
-
-        /* First we need some memory for this virtqueue. */
-        pages = (vring_size(num_descs, LGUEST_VRING_ALIGN) + getpagesize() - 1)
-                / getpagesize();
-        p = get_pages(pages);
 
         /* Initialize the virtqueue */
         vq->next = NULL;
         vq->last_avail_idx = 0;
         vq->dev = dev;
+        vq->name = name;
 
         /*
          * This is the routine the service thread will run, and its Process ID
@@ -1218,25 +2393,11 @@ static void add_virtqueue(struct device *dev, unsigned int num_descs,
         vq->thread = (pid_t)-1;
 
         /* Initialize the configuration. */
-        vq->config.num = num_descs;
-        vq->config.irq = devices.next_irq++;
-        vq->config.pfn = to_guest_phys(p) / getpagesize();
-
-        /* Initialize the vring. */
-        vring_init(&vq->vring, num_descs, p, LGUEST_VRING_ALIGN);
-
-        /*
-         * Append virtqueue to this device's descriptor.  We use
-         * device_config() to get the end of the device's current virtqueues;
-         * we check that we haven't added any config or feature information
-         * yet, otherwise we'd be overwriting them.
-         */
-        assert(dev->desc->config_len == 0 && dev->desc->feature_len == 0);
-        memcpy(device_config(dev), &vq->config, sizeof(vq->config));
-        dev->num_vq++;
-        dev->desc->num_vq++;
+        reset_vq_pci_config(vq);
+        vq->pci_config.queue_notify_off = 0;
 
-        verbose("Virtqueue page %#lx\n", to_guest_phys(p));
+        /* Add one to the number of queues */
+        vq->dev->mmio->cfg.num_queues++;
 
         /*
          * Add to tail of list, so dev->vq is first vq, dev->vq->next is
@@ -1246,73 +2407,239 @@ static void add_virtqueue(struct device *dev, unsigned int num_descs,
         *i = vq;
 }
 
-/*
- * The first half of the feature bitmask is for us to advertise features.  The
- * second half is for the Guest to accept features.
- */
-static void add_feature(struct device *dev, unsigned bit)
+/* The Guest accesses the feature bits via the PCI common config MMIO region */
+static void add_pci_feature(struct device *dev, unsigned bit)
 {
-        u8 *features = get_feature_bits(dev);
+        dev->features |= (1ULL << bit);
+}
 
-        /* We can't extend the feature bits once we've added config bytes */
-        if (dev->desc->feature_len <= bit / CHAR_BIT) {
-                assert(dev->desc->config_len == 0);
-                dev->feature_len = dev->desc->feature_len = (bit/CHAR_BIT) + 1;
-        }
+/* For devices with no config. */
+static void no_device_config(struct device *dev)
+{
+        dev->mmio_addr = get_mmio_region(dev->mmio_size);
 
-        features[bit / CHAR_BIT] |= (1 << (bit % CHAR_BIT));
+        dev->config.bar[0] = dev->mmio_addr;
+        /* Bottom 4 bits must be zero */
+        assert(~(dev->config.bar[0] & 0xF));
+}
+
+/* This puts the device config into BAR0 */
+static void set_device_config(struct device *dev, const void *conf, size_t len)
+{
+        /* Set up BAR 0 */
+        dev->mmio_size += len;
+        dev->mmio = realloc(dev->mmio, dev->mmio_size);
+        memcpy(dev->mmio + 1, conf, len);
+
+        /*
+         * 4.1.4.6:
+         *
+         *  The device MUST present at least one VIRTIO_PCI_CAP_DEVICE_CFG
+         *  capability for any device type which has a device-specific
+         *  configuration.
+         */
+        /* Hook up device cfg */
+        dev->config.cfg_access.cap.cap_next
+                = offsetof(struct pci_config, device);
+
+        /*
+         * 4.1.4.6.1:
+         *
+         *  The offset for the device-specific configuration MUST be 4-byte
+         *  aligned.
+         */
+        assert(dev->config.cfg_access.cap.cap_next % 4 == 0);
+
+        /* Fix up device cfg field length. */
+        dev->config.device.length = len;
+
+        /* The rest is the same as the no-config case */
+        no_device_config(dev);
+}
+
+static void init_cap(struct virtio_pci_cap *cap, size_t caplen, int type,
+                     size_t bar_offset, size_t bar_bytes, u8 next)
+{
+        cap->cap_vndr = PCI_CAP_ID_VNDR;
+        cap->cap_next = next;
+        cap->cap_len = caplen;
+        cap->cfg_type = type;
+        cap->bar = 0;
+        memset(cap->padding, 0, sizeof(cap->padding));
+        cap->offset = bar_offset;
+        cap->length = bar_bytes;
 }
 
 /*
- * This routine sets the configuration fields for an existing device's
- * descriptor.  It only works for the last device, but that's OK because that's
- * how we use it.
+ * This sets up the pci_config structure, as defined in the virtio 1.0
+ * standard (and PCI standard).
  */
-static void set_config(struct device *dev, unsigned len, const void *conf)
+static void init_pci_config(struct pci_config *pci, u16 type,
+                            u8 class, u8 subclass)
 {
-        /* Check we haven't overflowed our single page. */
-        if (device_config(dev) + len > devices.descpage + getpagesize())
-                errx(1, "Too many devices");
+        size_t bar_offset, bar_len;
+
+        /*
+         * 4.1.4.4.1:
+         *
+         *  The device MUST either present notify_off_multiplier as an even
+         *  power of 2, or present notify_off_multiplier as 0.
+         *
+         * 2.1.2:
+         *
+         *   The device MUST initialize device status to 0 upon reset. 
+         */
+        memset(pci, 0, sizeof(*pci));
+
+        /* 4.1.2.1: Devices MUST have the PCI Vendor ID 0x1AF4 */
+        pci->vendor_id = 0x1AF4;
+        /* 4.1.2.1: ... PCI Device ID calculated by adding 0x1040 ... */
+        pci->device_id = 0x1040 + type;
+
+        /*
+         * PCI have specific codes for different types of devices.
+         * Linux doesn't care, but it's a good clue for people looking
+         * at the device.
+         */
+        pci->class = class;
+        pci->subclass = subclass;
+
+        /*
+         * 4.1.2.1:
+         *
+         *  Non-transitional devices SHOULD have a PCI Revision ID of 1 or
+         *  higher
+         */
+        pci->revid = 1;
+
+        /*
+         * 4.1.2.1:
+         *
+         *  Non-transitional devices SHOULD have a PCI Subsystem Device ID of
+         *  0x40 or higher.
+         */
+        pci->subsystem_device_id = 0x40;
+
+        /* We use our dummy interrupt controller, and irq_line is the irq */
+        pci->irq_line = devices.next_irq++;
+        pci->irq_pin = 0;
+
+        /* Support for extended capabilities. */
+        pci->status = (1 << 4);
+
+        /* Link them in. */
+        /*
+         * 4.1.4.3.1:
+         *
+         *  The device MUST present at least one common configuration
+         *  capability.
+         */
+        pci->capabilities = offsetof(struct pci_config, common);
+
+        /* 4.1.4.3.1 ... offset MUST be 4-byte aligned. */
+        assert(pci->capabilities % 4 == 0);
+
+        bar_offset = offsetof(struct virtio_pci_mmio, cfg);
+        bar_len = sizeof(((struct virtio_pci_mmio *)0)->cfg);
+        init_cap(&pci->common, sizeof(pci->common), VIRTIO_PCI_CAP_COMMON_CFG,
+                 bar_offset, bar_len,
+                 offsetof(struct pci_config, notify));
+
+        /*
+         * 4.1.4.4.1:
+         *
+         *  The device MUST present at least one notification capability.
+         */
+        bar_offset += bar_len;
+        bar_len = sizeof(((struct virtio_pci_mmio *)0)->notify);
+
+        /*
+         * 4.1.4.4.1:
+         *
+         *  The cap.offset MUST be 2-byte aligned.
+         */
+        assert(pci->common.cap_next % 2 == 0);
+
+        /* FIXME: Use a non-zero notify_off, for per-queue notification? */
+        /*
+         * 4.1.4.4.1:
+         *
+         *  The value cap.length presented by the device MUST be at least 2 and
+         *  MUST be large enough to support queue notification offsets for all
+         *  supported queues in all possible configurations.
+         */
+        assert(bar_len >= 2);
+
+        init_cap(&pci->notify.cap, sizeof(pci->notify),
+                 VIRTIO_PCI_CAP_NOTIFY_CFG,
+                 bar_offset, bar_len,
+                 offsetof(struct pci_config, isr));
+
+        bar_offset += bar_len;
+        bar_len = sizeof(((struct virtio_pci_mmio *)0)->isr);
+        /*
+         * 4.1.4.5.1:
+         *
+         *  The device MUST present at least one VIRTIO_PCI_CAP_ISR_CFG
+         *  capability.
+         */
+        init_cap(&pci->isr, sizeof(pci->isr),
+                 VIRTIO_PCI_CAP_ISR_CFG,
+                 bar_offset, bar_len,
+                 offsetof(struct pci_config, cfg_access));
+
+        /*
+         * 4.1.4.7.1:
+         *
+         * The device MUST present at least one VIRTIO_PCI_CAP_PCI_CFG
+         * capability.
+         */
+        /* This doesn't have any presence in the BAR */
+        init_cap(&pci->cfg_access.cap, sizeof(pci->cfg_access),
+                 VIRTIO_PCI_CAP_PCI_CFG,
+                 0, 0, 0);
 
-        /* Copy in the config information, and store the length. */
-        memcpy(device_config(dev), conf, len);
-        dev->desc->config_len = len;
+        bar_offset += bar_len + sizeof(((struct virtio_pci_mmio *)0)->padding);
+        assert(bar_offset == sizeof(struct virtio_pci_mmio));
 
-        /* Size must fit in config_len field (8 bits)! */
-        assert(dev->desc->config_len == len);
+        /*
+         * This gets sewn in and length set in set_device_config().
+         * Some devices don't have a device configuration interface, so
+         * we never expose this if we don't call set_device_config().
+         */
+        init_cap(&pci->device, sizeof(pci->device), VIRTIO_PCI_CAP_DEVICE_CFG,
+                 bar_offset, 0, 0);
 }
 
 /*
- * This routine does all the creation and setup of a new device, including
- * calling new_dev_desc() to allocate the descriptor and device memory.  We
- * don't actually start the service threads until later.
+ * This routine does all the creation and setup of a new device, but we don't
+ * actually place the MMIO region until we know the size (if any) of the
+ * device-specific config.  And we don't actually start the service threads
+ * until later.
  *
  * See what I mean about userspace being boring?
  */
-static struct device *new_device(const char *name, u16 type)
+static struct device *new_pci_device(const char *name, u16 type,
+                                     u8 class, u8 subclass)
 {
         struct device *dev = malloc(sizeof(*dev));
 
         /* Now we populate the fields one at a time. */
-        dev->desc = new_dev_desc(type);
         dev->name = name;
         dev->vq = NULL;
-        dev->feature_len = 0;
-        dev->num_vq = 0;
         dev->running = false;
-        dev->next = NULL;
+        dev->wrote_features_ok = false;
+        dev->mmio_size = sizeof(struct virtio_pci_mmio);
+        dev->mmio = calloc(1, dev->mmio_size);
+        dev->features = (u64)1 << VIRTIO_F_VERSION_1;
+        dev->features_accepted = 0;
 
-        /*
-         * Append to device list.  Prepending to a single-linked list is
-         * easier, but the user expects the devices to be arranged on the bus
-         * in command-line order.  The first network device on the command line
-         * is eth0, the first block device /dev/vda, etc.
-         */
-        if (devices.lastdev)
-                devices.lastdev->next = dev;
-        else
-                devices.dev = dev;
-        devices.lastdev = dev;
+        if (devices.device_num + 1 >= MAX_PCI_DEVICES)
+                errx(1, "Can only handle 31 PCI devices");
+
+        init_pci_config(&dev->config, type, class, subclass);
+        assert(!devices.pci[devices.device_num+1]);
+        devices.pci[++devices.device_num] = dev;
 
         return dev;
 }
@@ -1324,6 +2651,7 @@ static struct device *new_device(const char *name, u16 type)
 static void setup_console(void)
 {
         struct device *dev;
+        struct virtio_console_config conf;
 
         /* If we can save the initial standard input settings... */
         if (tcgetattr(STDIN_FILENO, &orig_term) == 0) {
@@ -1336,7 +2664,7 @@ static void setup_console(void)
                 tcsetattr(STDIN_FILENO, TCSANOW, &term);
         }
 
-        dev = new_device("console", VIRTIO_ID_CONSOLE);
+        dev = new_pci_device("console", VIRTIO_ID_CONSOLE, 0x07, 0x00);
 
         /* We store the console state in dev->priv, and initialize it. */
         dev->priv = malloc(sizeof(struct console_abort));
@@ -1348,10 +2676,14 @@ static void setup_console(void)
          * stdin.  When they put something in the output queue, we write it to
          * stdout.
          */
-        add_virtqueue(dev, VIRTQUEUE_NUM, console_input);
-        add_virtqueue(dev, VIRTQUEUE_NUM, console_output);
+        add_pci_virtqueue(dev, console_input, "input");
+        add_pci_virtqueue(dev, console_output, "output");
+
+        /* We need a configuration area for the emerg_wr early writes. */
+        add_pci_feature(dev, VIRTIO_CONSOLE_F_EMERG_WRITE);
+        set_device_config(dev, &conf, sizeof(conf));
 
-        verbose("device %u: console\n", ++devices.device_num);
+        verbose("device %u: console\n", devices.device_num);
 }
 /*:*/
 
@@ -1449,6 +2781,7 @@ static void configure_device(int fd, const char *tapif, u32 ipaddr)
 static int get_tun_device(char tapif[IFNAMSIZ])
 {
         struct ifreq ifr;
+        int vnet_hdr_sz;
         int netfd;
 
         /* Start with this zeroed.  Messy but sure. */
@@ -1476,6 +2809,18 @@ static int get_tun_device(char tapif[IFNAMSIZ])
          */
         ioctl(netfd, TUNSETNOCSUM, 1);
 
+        /*
+         * In virtio before 1.0 (aka legacy virtio), we added a 16-bit
+         * field at the end of the network header iff
+         * VIRTIO_NET_F_MRG_RXBUF was negotiated.  For virtio 1.0,
+         * that became the norm, but we need to tell the tun device
+         * about our expanded header (which is called
+         * virtio_net_hdr_mrg_rxbuf in the legacy system).
+         */
+        vnet_hdr_sz = sizeof(struct virtio_net_hdr_v1);
+        if (ioctl(netfd, TUNSETVNETHDRSZ, &vnet_hdr_sz) != 0)
+                err(1, "Setting tun header size to %u", vnet_hdr_sz);
+
         memcpy(tapif, ifr.ifr_name, IFNAMSIZ);
         return netfd;
 }
@@ -1499,12 +2844,12 @@ static void setup_tun_net(char *arg)
         net_info->tunfd = get_tun_device(tapif);
 
         /* First we create a new network device. */
-        dev = new_device("net", VIRTIO_ID_NET);
+        dev = new_pci_device("net", VIRTIO_ID_NET, 0x02, 0x00);
         dev->priv = net_info;
 
         /* Network devices need a recv and a send queue, just like console. */
-        add_virtqueue(dev, VIRTQUEUE_NUM, net_input);
-        add_virtqueue(dev, VIRTQUEUE_NUM, net_output);
+        add_pci_virtqueue(dev, net_input, "rx");
+        add_pci_virtqueue(dev, net_output, "tx");
 
         /*
          * We need a socket to perform the magic network ioctls to bring up the
@@ -1524,7 +2869,7 @@ static void setup_tun_net(char *arg)
         p = strchr(arg, ':');
         if (p) {
                 str2mac(p+1, conf.mac);
-                add_feature(dev, VIRTIO_NET_F_MAC);
+                add_pci_feature(dev, VIRTIO_NET_F_MAC);
                 *p = '\0';
         }
 
@@ -1538,25 +2883,21 @@ static void setup_tun_net(char *arg)
         configure_device(ipfd, tapif, ip);
 
         /* Expect Guest to handle everything except UFO */
-        add_feature(dev, VIRTIO_NET_F_CSUM);
-        add_feature(dev, VIRTIO_NET_F_GUEST_CSUM);
-        add_feature(dev, VIRTIO_NET_F_GUEST_TSO4);
-        add_feature(dev, VIRTIO_NET_F_GUEST_TSO6);
-        add_feature(dev, VIRTIO_NET_F_GUEST_ECN);
-        add_feature(dev, VIRTIO_NET_F_HOST_TSO4);
-        add_feature(dev, VIRTIO_NET_F_HOST_TSO6);
-        add_feature(dev, VIRTIO_NET_F_HOST_ECN);
+        add_pci_feature(dev, VIRTIO_NET_F_CSUM);
+        add_pci_feature(dev, VIRTIO_NET_F_GUEST_CSUM);
+        add_pci_feature(dev, VIRTIO_NET_F_GUEST_TSO4);
+        add_pci_feature(dev, VIRTIO_NET_F_GUEST_TSO6);
+        add_pci_feature(dev, VIRTIO_NET_F_GUEST_ECN);
+        add_pci_feature(dev, VIRTIO_NET_F_HOST_TSO4);
+        add_pci_feature(dev, VIRTIO_NET_F_HOST_TSO6);
+        add_pci_feature(dev, VIRTIO_NET_F_HOST_ECN);
         /* We handle indirect ring entries */
-        add_feature(dev, VIRTIO_RING_F_INDIRECT_DESC);
-        /* We're compliant with the damn spec. */
-        add_feature(dev, VIRTIO_F_ANY_LAYOUT);
-        set_config(dev, sizeof(conf), &conf);
+        add_pci_feature(dev, VIRTIO_RING_F_INDIRECT_DESC);
+        set_device_config(dev, &conf, sizeof(conf));
 
         /* We don't need the socket any more; setup is done. */
         close(ipfd);
 
-        devices.device_num++;
-
         if (bridging)
                 verbose("device %u: tun %s attached to bridge: %s\n",
                         devices.device_num, tapif, arg);
@@ -1607,7 +2948,7 @@ static void blk_request(struct virtqueue *vq)
         head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
 
         /* Copy the output header from the front of the iov (adjusts iov) */
-        iov_consume(iov, out_num, &out, sizeof(out));
+        iov_consume(vq->dev, iov, out_num, &out, sizeof(out));
 
         /* Find and trim end of iov input array, for our status byte. */
         in = NULL;
@@ -1619,7 +2960,7 @@ static void blk_request(struct virtqueue *vq)
                 }
         }
         if (!in)
-                errx(1, "Bad virtblk cmd with no room for status");
+                bad_driver_vq(vq, "Bad virtblk cmd with no room for status");
 
         /*
          * For historical reasons, block operations are expressed in 512 byte
@@ -1627,15 +2968,7 @@ static void blk_request(struct virtqueue *vq)
          */
         off = out.sector * 512;
 
-        /*
-         * In general the virtio block driver is allowed to try SCSI commands.
-         * It'd be nice if we supported eject, for example, but we don't.
-         */
-        if (out.type & VIRTIO_BLK_T_SCSI_CMD) {
-                fprintf(stderr, "Scsi commands unsupported\n");
-                *in = VIRTIO_BLK_S_UNSUPP;
-                wlen = sizeof(*in);
-        } else if (out.type & VIRTIO_BLK_T_OUT) {
+        if (out.type & VIRTIO_BLK_T_OUT) {
                 /*
                  * Write
                  *
@@ -1657,7 +2990,7 @@ static void blk_request(struct virtqueue *vq)
                         /* Trim it back to the correct length */
                         ftruncate64(vblk->fd, vblk->len);
                         /* Die, bad Guest, die. */
-                        errx(1, "Write past end %llu+%u", off, ret);
+                        bad_driver_vq(vq, "Write past end %llu+%u", off, ret);
                 }
 
                 wlen = sizeof(*in);
@@ -1699,11 +3032,11 @@ static void setup_block_file(const char *filename)
         struct vblk_info *vblk;
         struct virtio_blk_config conf;
 
-        /* Creat the device. */
-        dev = new_device("block", VIRTIO_ID_BLOCK);
+        /* Create the device. */
+        dev = new_pci_device("block", VIRTIO_ID_BLOCK, 0x01, 0x80);
 
         /* The device has one virtqueue, where the Guest places requests. */
-        add_virtqueue(dev, VIRTQUEUE_NUM, blk_request);
+        add_pci_virtqueue(dev, blk_request, "request");
 
         /* Allocate the room for our own bookkeeping */
         vblk = dev->priv = malloc(sizeof(*vblk));
@@ -1712,9 +3045,6 @@ static void setup_block_file(const char *filename)
         vblk->fd = open_or_die(filename, O_RDWR|O_LARGEFILE);
         vblk->len = lseek64(vblk->fd, 0, SEEK_END);
 
-        /* We support FLUSH. */
-        add_feature(dev, VIRTIO_BLK_F_FLUSH);
-
         /* Tell Guest how many sectors this device has. */
         conf.capacity = cpu_to_le64(vblk->len / 512);
 
@@ -1722,20 +3052,19 @@ static void setup_block_file(const char *filename)
          * Tell Guest not to put in too many descriptors at once: two are used
          * for the in and out elements.
          */
-        add_feature(dev, VIRTIO_BLK_F_SEG_MAX);
+        add_pci_feature(dev, VIRTIO_BLK_F_SEG_MAX);
         conf.seg_max = cpu_to_le32(VIRTQUEUE_NUM - 2);
 
-        /* Don't try to put whole struct: we have 8 bit limit. */
-        set_config(dev, offsetof(struct virtio_blk_config, geometry), &conf);
+        set_device_config(dev, &conf, sizeof(struct virtio_blk_config));
 
         verbose("device %u: virtblock %llu sectors\n",
-                ++devices.device_num, le64_to_cpu(conf.capacity));
+                devices.device_num, le64_to_cpu(conf.capacity));
 }
 
 /*L:211
- * Our random number generator device reads from /dev/random into the Guest's
+ * Our random number generator device reads from /dev/urandom into the Guest's
  * input buffers.  The usual case is that the Guest doesn't want random numbers
- * and so has no buffers although /dev/random is still readable, whereas
+ * and so has no buffers although /dev/urandom is still readable, whereas
  * console is the reverse.
  *
  * The same logic applies, however.
@@ -1754,7 +3083,7 @@ static void rng_input(struct virtqueue *vq)
         /* First we need a buffer from the Guests's virtqueue. */
         head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
         if (out_num)
-                errx(1, "Output buffers in rng?");
+                bad_driver_vq(vq, "Output buffers in rng?");
 
         /*
          * Just like the console write, we loop to cover the whole iovec.
@@ -1763,8 +3092,8 @@ static void rng_input(struct virtqueue *vq)
         while (!iov_empty(iov, in_num)) {
                 len = readv(rng_info->rfd, iov, in_num);
                 if (len <= 0)
-                        err(1, "Read from /dev/random gave %i", len);
-                iov_consume(iov, in_num, NULL, len);
+                        err(1, "Read from /dev/urandom gave %i", len);
+                iov_consume(vq->dev, iov, in_num, NULL, len);
                 totlen += len;
         }
 
@@ -1780,17 +3109,20 @@ static void setup_rng(void)
         struct device *dev;
         struct rng_info *rng_info = malloc(sizeof(*rng_info));
 
-        /* Our device's privat info simply contains the /dev/random fd. */
-        rng_info->rfd = open_or_die("/dev/random", O_RDONLY);
+        /* Our device's private info simply contains the /dev/urandom fd. */
+        rng_info->rfd = open_or_die("/dev/urandom", O_RDONLY);
 
         /* Create the new device. */
-        dev = new_device("rng", VIRTIO_ID_RNG);
+        dev = new_pci_device("rng", VIRTIO_ID_RNG, 0xff, 0);
         dev->priv = rng_info;
 
         /* The device has one virtqueue, where the Guest places inbufs. */
-        add_virtqueue(dev, VIRTQUEUE_NUM, rng_input);
+        add_pci_virtqueue(dev, rng_input, "input");
 
-        verbose("device %u: rng\n", devices.device_num++);
+        /* We don't have any configuration space */
+        no_device_config(dev);
+
+        verbose("device %u: rng\n", devices.device_num);
 }
 /* That's the end of device setup. */
 
@@ -1820,17 +3152,23 @@ static void __attribute__((noreturn)) restart_guest(void)
 static void __attribute__((noreturn)) run_guest(void)
 {
         for (;;) {
-                unsigned long notify_addr;
+                struct lguest_pending notify;
                 int readval;
 
                 /* We read from the /dev/lguest device to run the Guest. */
-                readval = pread(lguest_fd, &notify_addr,
-                                sizeof(notify_addr), cpu_id);
-
-                /* One unsigned long means the Guest did HCALL_NOTIFY */
-                if (readval == sizeof(notify_addr)) {
-                        verbose("Notify on address %#lx\n", notify_addr);
-                        handle_output(notify_addr);
+                readval = pread(lguest_fd, &notify, sizeof(notify), cpu_id);
+                if (readval == sizeof(notify)) {
+                        if (notify.trap == 13) {
+                                verbose("Emulating instruction at %#x\n",
+                                        getreg(eip));
+                                emulate_insn(notify.insn);
+                        } else if (notify.trap == 14) {
+                                verbose("Emulating MMIO at %#x\n",
+                                        getreg(eip));
+                                emulate_mmio(notify.addr, notify.insn);
+                        } else
+                                errx(1, "Unknown trap %i addr %#08x\n",
+                                     notify.trap, notify.addr);
                 /* ENOENT means the Guest died.  Reading tells us why. */
                 } else if (errno == ENOENT) {
                         char reason[1024] = { 0 };
@@ -1893,11 +3231,9 @@ int main(int argc, char *argv[])
         main_args = argv;
 
         /*
-         * First we initialize the device list.  We keep a pointer to the last
-         * device, and the next interrupt number to use for devices (1:
-         * remember that 0 is used by the timer).
+         * First we initialize the device list.  We remember next interrupt
+         * number to use for devices (1: remember that 0 is used by the timer).
          */
-        devices.lastdev = NULL;
         devices.next_irq = 1;
 
         /* We're CPU 0.  In fact, that's the only CPU possible right now. */
@@ -1921,12 +3257,14 @@ int main(int argc, char *argv[])
                         guest_base = map_zeroed_pages(mem / getpagesize()
                                                       + DEVICE_PAGES);
                         guest_limit = mem;
-                        guest_max = mem + DEVICE_PAGES*getpagesize();
-                        devices.descpage = get_pages(1);
+                        guest_max = guest_mmio = mem + DEVICE_PAGES*getpagesize();
                         break;
                 }
         }
 
+        /* We always have a console device, and it's always device 1. */
+        setup_console();
+
         /* The options are fairly straight-forward */
         while ((c = getopt_long(argc, argv, "v", opts, NULL)) != EOF) {
                 switch (c) {
@@ -1967,8 +3305,8 @@ int main(int argc, char *argv[])
 
         verbose("Guest base is at %p\n", guest_base);
 
-        /* We always have a console device */
-        setup_console();
+        /* Initialize the (fake) PCI host bridge device. */
+        init_pci_host_bridge();
 
         /* Now we load the kernel */
         start = load_kernel(open_or_die(argv[optind+1], O_RDONLY));