1 files changed, 131 insertions, 9 deletions

diff --git a/tools/lguest/lguest.c b/tools/lguest/lguest.c
index b00263f5febb..10a72b810127 100644
--- a/tools/lguest/lguest.c
+++ b/tools/lguest/lguest.c
@@ -673,7 +673,13 @@ static void trigger_irq(struct virtqueue *vq)
                 return;
         }
 
-        /* Set isr to 1 (queue interrupt pending) */
+        /*
+         * 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. */
@@ -1304,11 +1310,19 @@ static bool pci_data_iowrite(u16 port, u32 mask, u32 val)
         } 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;
 
-                /* First copy what they wrote into the window */
                 iowrite(portoff, val, mask, &d->config.cfg_access.pci_cfg_data);
 
                 /*
@@ -1346,6 +1360,14 @@ static void pci_data_ioread(u16 port, u32 mask, u32 *val)
         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))
                         errx(1, "Invalid cfg_access to bar%u, offset %u len %u",
@@ -1704,6 +1726,13 @@ static void emulate_mmio_write(struct device *d, u32 off, u32 val, u32 mask)
 
         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)
@@ -1731,12 +1760,23 @@ static void emulate_mmio_write(struct device *d, u32 off, u32 val, u32 mask)
                 goto write_through32;
         case offsetof(struct virtio_pci_mmio, cfg.device_status):
                 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;
         case offsetof(struct virtio_pci_mmio, cfg.queue_select):
                 vq = vq_by_num(d, val);
-                /* Out of range?  Return size 0 */
+                /*
+                 * 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;
@@ -1841,6 +1881,17 @@ static u32 emulate_mmio_read(struct device *d, u32 off, u32 mask)
                 goto read_through16;
         case offsetof(struct virtio_pci_mmio, cfg.device_status):
         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):
                 goto read_through16;
@@ -1848,8 +1899,12 @@ static u32 emulate_mmio_read(struct device *d, u32 off, u32 mask)
                 if (mask != 0xFF)
                         errx(1, "%s: non-8-bit read from offset %u (%#x)",
                              d->name, off, getreg(eip));
-                /* Read resets the isr */
                 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):
@@ -2008,10 +2063,25 @@ static void set_device_config(struct device *dev, const void *conf, size_t 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;
 
@@ -2041,7 +2111,12 @@ static void init_pci_config(struct pci_config *pci, u16 type,
 {
         size_t bar_offset, bar_len;
 
-        /* Save typing: most thing are happy being zero. */
+        /*
+         * 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.
+         */
         memset(pci, 0, sizeof(*pci));
 
         /* 4.1.2.1: Devices MUST have the PCI Vendor ID 0x1AF4 */
@@ -2058,14 +2133,18 @@ static void init_pci_config(struct pci_config *pci, u16 type,
         pci->subclass = subclass;
 
         /*
-         * 4.1.2.1 Non-transitional devices SHOULD have a PCI Revision
-         * ID of 1 or higher
+         * 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.
+         * 4.1.2.1:
+         *
+         *  Non-transitional devices SHOULD have a PCI Subsystem Device ID of
+         *  0x40 or higher.
          */
         pci->subsystem_device_id = 0x40;
 
@@ -2077,17 +2156,48 @@ static void init_pci_config(struct pci_config *pci, u16 type,
         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,
@@ -2095,11 +2205,23 @@ static void init_pci_config(struct pci_config *pci, u16 type,
 
         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,