virtio_pci: modern driver

Lightly tested against qemu.

One thing *not* implemented here is separate mappings
for descriptor/avail/used rings. That's nice to have,
will be done later after we have core support.

This also exposes the PCI layout to userspace, and
adds macros for PCI layout offsets:

QEMU wants it, so why not?  Trust, but verify.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

4 files changed, 621 insertions, 7 deletions

diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile
index bf5104b56894..bd230d1c0533 100644
--- a/drivers/virtio/Makefile
+++ b/drivers/virtio/Makefile
@@ -1,5 +1,5 @@
 obj-$(CONFIG_VIRTIO) += virtio.o virtio_ring.o
 obj-$(CONFIG_VIRTIO_MMIO) += virtio_mmio.o
 obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o
-virtio_pci-y := virtio_pci_legacy.o virtio_pci_common.o
+virtio_pci-y := virtio_pci_modern.o virtio_pci_legacy.o virtio_pci_common.o
 obj-$(CONFIG_VIRTIO_BALLOON) += virtio_balloon.o
diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index 457cbe29c8c4..8ae34a34f3af 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -505,7 +505,9 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
         if (rc)
                 goto err_request_regions;
 
-        rc = virtio_pci_legacy_probe(vp_dev);
+        rc = virtio_pci_modern_probe(vp_dev);
+        if (rc == -ENODEV)
+                rc = virtio_pci_legacy_probe(vp_dev);
         if (rc)
                 goto err_probe;
 
@@ -518,7 +520,10 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
         return 0;
 
 err_register:
-        virtio_pci_legacy_remove(vp_dev);
+        if (vp_dev->ioaddr)
+             virtio_pci_legacy_remove(vp_dev);
+        else
+             virtio_pci_modern_remove(vp_dev);
 err_probe:
         pci_release_regions(pci_dev);
 err_request_regions:
@@ -534,7 +539,10 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
 
         unregister_virtio_device(&vp_dev->vdev);
 
-        virtio_pci_legacy_remove(pci_dev);
+        if (vp_dev->ioaddr)
+                virtio_pci_legacy_remove(vp_dev);
+        else
+                virtio_pci_modern_remove(vp_dev);
 
         pci_release_regions(pci_dev);
         pci_disable_device(pci_dev);
diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h
index 2b1e70db44a0..610c43f19230 100644
--- a/drivers/virtio/virtio_pci_common.h
+++ b/drivers/virtio/virtio_pci_common.h
@@ -53,12 +53,29 @@ struct virtio_pci_device {
         struct virtio_device vdev;
         struct pci_dev *pci_dev;
 
+        /* In legacy mode, these two point to within ->legacy. */
+        /* Where to read and clear interrupt */
+        u8 __iomem *isr;
+
+        /* Modern only fields */
+        /* The IO mapping for the PCI config space (non-legacy mode) */
+        struct virtio_pci_common_cfg __iomem *common;
+        /* Device-specific data (non-legacy mode)  */
+        void __iomem *device;
+
+        /* So we can sanity-check accesses. */
+        size_t device_len;
+
+        /* Capability for when we need to map notifications per-vq. */
+        int notify_map_cap;
+
+        /* Multiply queue_notify_off by this value. (non-legacy mode). */
+        u32 notify_offset_multiplier;
+
+        /* Legacy only field */
         /* the IO mapping for the PCI config space */
         void __iomem *ioaddr;
 
-        /* the IO mapping for ISR operation */
-        void __iomem *isr;
-
         /* a list of queues so we can dispatch IRQs */
         spinlock_t lock;
         struct list_head virtqueues;
@@ -129,5 +146,7 @@ int vp_set_vq_affinity(struct virtqueue *vq, int cpu);
 
 int virtio_pci_legacy_probe(struct virtio_pci_device *);
 void virtio_pci_legacy_remove(struct virtio_pci_device *);
+int virtio_pci_modern_probe(struct virtio_pci_device *);
+void virtio_pci_modern_remove(struct virtio_pci_device *);
 
 #endif
diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
new file mode 100644
index 000000000000..a3d81013e0c2
--- /dev/null
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -0,0 +1,587 @@
+/*
+ * Virtio PCI driver - modern (virtio 1.0) device support
+ *
+ * This module allows virtio devices to be used over a virtual PCI device.
+ * This can be used with QEMU based VMMs like KVM or Xen.
+ *
+ * Copyright IBM Corp. 2007
+ * Copyright Red Hat, Inc. 2014
+ *
+ * Authors:
+ *  Anthony Liguori  <aliguori@us.ibm.com>
+ *  Rusty Russell <rusty@rustcorp.com.au>
+ *  Michael S. Tsirkin <mst@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#define VIRTIO_PCI_NO_LEGACY
+#include "virtio_pci_common.h"
+
+static void __iomem *map_capability(struct pci_dev *dev, int off,
+                                    size_t minlen,
+                                    u32 align,
+                                    u32 start, u32 size,
+                                    size_t *len)
+{
+        u8 bar;
+        u32 offset, length;
+        void __iomem *p;
+
+        pci_read_config_byte(dev, off + offsetof(struct virtio_pci_cap,
+                                                 bar),
+                             &bar);
+        pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, offset),
+                             &offset);
+        pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length),
+                              &length);
+
+        if (length <= start) {
+                dev_err(&dev->dev,
+                        "virtio_pci: bad capability len %u (>%u expected)\n",
+                        length, start);
+                return NULL;
+        }
+
+        if (length - start < minlen) {
+                dev_err(&dev->dev,
+                        "virtio_pci: bad capability len %u (>=%zu expected)\n",
+                        length, minlen);
+                return NULL;
+        }
+
+        length -= start;
+
+        if (start + offset < offset) {
+                dev_err(&dev->dev,
+                        "virtio_pci: map wrap-around %u+%u\n",
+                        start, offset);
+                return NULL;
+        }
+
+        offset += start;
+
+        if (offset & (align - 1)) {
+                dev_err(&dev->dev,
+                        "virtio_pci: offset %u not aligned to %u\n",
+                        offset, align);
+                return NULL;
+        }
+
+        if (length > size)
+                length = size;
+
+        if (len)
+                *len = length;
+
+        if (minlen + offset < minlen ||
+            minlen + offset > pci_resource_len(dev, bar)) {
+                dev_err(&dev->dev,
+                        "virtio_pci: map virtio %zu@%u "
+                        "out of range on bar %i length %lu\n",
+                        minlen, offset,
+                        bar, (unsigned long)pci_resource_len(dev, bar));
+                return NULL;
+        }
+
+        p = pci_iomap_range(dev, bar, offset, length);
+        if (!p)
+                dev_err(&dev->dev,
+                        "virtio_pci: unable to map virtio %u@%u on bar %i\n",
+                        length, offset, bar);
+        return p;
+}
+
+static void iowrite64_twopart(u64 val, __le32 __iomem *lo, __le32 __iomem *hi)
+{
+        iowrite32((u32)val, lo);
+        iowrite32(val >> 32, hi);
+}
+
+/* virtio config->get_features() implementation */
+static u64 vp_get_features(struct virtio_device *vdev)
+{
+        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+        u64 features;
+
+        iowrite32(0, &vp_dev->common->device_feature_select);
+        features = ioread32(&vp_dev->common->device_feature);
+        iowrite32(1, &vp_dev->common->device_feature_select);
+        features |= ((u64)ioread32(&vp_dev->common->device_feature) << 32);
+
+        return features;
+}
+
+/* virtio config->finalize_features() implementation */
+static int vp_finalize_features(struct virtio_device *vdev)
+{
+        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+
+        /* Give virtio_ring a chance to accept features. */
+        vring_transport_features(vdev);
+
+        if (!__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
+                dev_err(&vdev->dev, "virtio: device uses modern interface "
+                        "but does not have VIRTIO_F_VERSION_1\n");
+                return -EINVAL;
+        }
+
+        iowrite32(0, &vp_dev->common->guest_feature_select);
+        iowrite32((u32)vdev->features, &vp_dev->common->guest_feature);
+        iowrite32(1, &vp_dev->common->guest_feature_select);
+        iowrite32(vdev->features >> 32, &vp_dev->common->guest_feature);
+
+        return 0;
+}
+
+/* virtio config->get() implementation */
+static void vp_get(struct virtio_device *vdev, unsigned offset,
+                   void *buf, unsigned len)
+{
+        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+        u8 b;
+        __le16 w;
+        __le32 l;
+
+        BUG_ON(offset + len > vp_dev->device_len);
+
+        switch (len) {
+        case 1:
+                b = ioread8(vp_dev->device + offset);
+                memcpy(buf, &b, sizeof b);
+                break;
+        case 2:
+                w = cpu_to_le16(ioread16(vp_dev->device + offset));
+                memcpy(buf, &w, sizeof w);
+                break;
+        case 4:
+                l = cpu_to_le32(ioread32(vp_dev->device + offset));
+                memcpy(buf, &l, sizeof l);
+                break;
+        case 8:
+                l = cpu_to_le32(ioread32(vp_dev->device + offset));
+                memcpy(buf, &l, sizeof l);
+                l = cpu_to_le32(ioread32(vp_dev->device + offset + sizeof l));
+                memcpy(buf + sizeof l, &l, sizeof l);
+                break;
+        default:
+                BUG();
+        }
+}
+
+/* the config->set() implementation.  it's symmetric to the config->get()
+ * implementation */
+static void vp_set(struct virtio_device *vdev, unsigned offset,
+                   const void *buf, unsigned len)
+{
+        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+        u8 b;
+        __le16 w;
+        __le32 l;
+
+        BUG_ON(offset + len > vp_dev->device_len);
+
+        switch (len) {
+        case 1:
+                memcpy(&b, buf, sizeof b);
+                iowrite8(b, vp_dev->device + offset);
+                break;
+        case 2:
+                memcpy(&w, buf, sizeof w);
+                iowrite16(le16_to_cpu(w), vp_dev->device + offset);
+                break;
+        case 4:
+                memcpy(&l, buf, sizeof l);
+                iowrite32(le32_to_cpu(l), vp_dev->device + offset);
+                break;
+        case 8:
+                memcpy(&l, buf, sizeof l);
+                iowrite32(le32_to_cpu(l), vp_dev->device + offset);
+                memcpy(&l, buf + sizeof l, sizeof l);
+                iowrite32(le32_to_cpu(l), vp_dev->device + offset + sizeof l);
+                break;
+        default:
+                BUG();
+        }
+}
+
+static u32 vp_generation(struct virtio_device *vdev)
+{
+        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+        return ioread8(&vp_dev->common->config_generation);
+}
+
+/* config->{get,set}_status() implementations */
+static u8 vp_get_status(struct virtio_device *vdev)
+{
+        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+        return ioread8(&vp_dev->common->device_status);
+}
+
+static void vp_set_status(struct virtio_device *vdev, u8 status)
+{
+        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+        /* We should never be setting status to 0. */
+        BUG_ON(status == 0);
+        iowrite8(status, &vp_dev->common->device_status);
+}
+
+static void vp_reset(struct virtio_device *vdev)
+{
+        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+        /* 0 status means a reset. */
+        iowrite8(0, &vp_dev->common->device_status);
+        /* Flush out the status write, and flush in device writes,
+         * including MSI-X interrupts, if any. */
+        ioread8(&vp_dev->common->device_status);
+        /* Flush pending VQ/configuration callbacks. */
+        vp_synchronize_vectors(vdev);
+}
+
+static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
+{
+        /* Setup the vector used for configuration events */
+        iowrite16(vector, &vp_dev->common->msix_config);
+        /* Verify we had enough resources to assign the vector */
+        /* Will also flush the write out to device */
+        return ioread16(&vp_dev->common->msix_config);
+}
+
+static size_t vring_pci_size(u16 num)
+{
+        /* We only need a cacheline separation. */
+        return PAGE_ALIGN(vring_size(num, SMP_CACHE_BYTES));
+}
+
+static void *alloc_virtqueue_pages(int *num)
+{
+        void *pages;
+
+        /* TODO: allocate each queue chunk individually */
+        for (; *num && vring_pci_size(*num) > PAGE_SIZE; *num /= 2) {
+                pages = alloc_pages_exact(vring_pci_size(*num),
+                                          GFP_KERNEL|__GFP_ZERO|__GFP_NOWARN);
+                if (pages)
+                        return pages;
+        }
+
+        if (!*num)
+                return NULL;
+
+        /* Try to get a single page. You are my only hope! */
+        return alloc_pages_exact(vring_pci_size(*num), GFP_KERNEL|__GFP_ZERO);
+}
+
+static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
+                                  struct virtio_pci_vq_info *info,
+                                  unsigned index,
+                                  void (*callback)(struct virtqueue *vq),
+                                  const char *name,
+                                  u16 msix_vec)
+{
+        struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
+        struct virtqueue *vq;
+        u16 num, off;
+        int err;
+
+        if (index >= ioread16(&cfg->num_queues))
+                return ERR_PTR(-ENOENT);
+
+        /* Select the queue we're interested in */
+        iowrite16(index, &cfg->queue_select);
+
+        /* Check if queue is either not available or already active. */
+        num = ioread16(&cfg->queue_size);
+        if (!num || ioread8(&cfg->queue_enable))
+                return ERR_PTR(-ENOENT);
+
+        if (num & (num - 1)) {
+                dev_warn(&vp_dev->pci_dev->dev, "bad queue size %u", num);
+                return ERR_PTR(-EINVAL);
+        }
+
+        /* get offset of notification word for this vq */
+        off = ioread16(&cfg->queue_notify_off);
+
+        info->num = num;
+        info->msix_vector = msix_vec;
+
+        info->queue = alloc_virtqueue_pages(&info->num);
+        if (info->queue == NULL)
+                return ERR_PTR(-ENOMEM);
+
+        /* create the vring */
+        vq = vring_new_virtqueue(index, info->num,
+                                 SMP_CACHE_BYTES, &vp_dev->vdev,
+                                 true, info->queue, vp_notify, callback, name);
+        if (!vq) {
+                err = -ENOMEM;
+                goto err_new_queue;
+        }
+
+        /* activate the queue */
+        iowrite16(num, &cfg->queue_size);
+        iowrite64_twopart(virt_to_phys(info->queue),
+                          &cfg->queue_desc_lo, &cfg->queue_desc_hi);
+        iowrite64_twopart(virt_to_phys(virtqueue_get_avail(vq)),
+                          &cfg->queue_avail_lo, &cfg->queue_avail_hi);
+        iowrite64_twopart(virt_to_phys(virtqueue_get_used(vq)),
+                          &cfg->queue_used_lo, &cfg->queue_used_hi);
+
+        vq->priv = (void __force *)map_capability(vp_dev->pci_dev,
+                                  vp_dev->notify_map_cap, 2, 2,
+                                  off * vp_dev->notify_offset_multiplier, 2,
+                                  NULL);
+
+        if (!vq->priv) {
+                err = -ENOMEM;
+                goto err_map_notify;
+        }
+
+        if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
+                iowrite16(msix_vec, &cfg->queue_msix_vector);
+                msix_vec = ioread16(&cfg->queue_msix_vector);
+                if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
+                        err = -EBUSY;
+                        goto err_assign_vector;
+                }
+        }
+
+        return vq;
+
+err_assign_vector:
+        pci_iounmap(vp_dev->pci_dev, (void __iomem __force *)vq->priv);
+err_map_notify:
+        vring_del_virtqueue(vq);
+err_new_queue:
+        free_pages_exact(info->queue, vring_pci_size(info->num));
+        return ERR_PTR(err);
+}
+
+static int vp_modern_find_vqs(struct virtio_device *vdev, unsigned nvqs,
+                              struct virtqueue *vqs[],
+                              vq_callback_t *callbacks[],
+                              const char *names[])
+{
+        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+        struct virtqueue *vq;
+        int rc = vp_find_vqs(vdev, nvqs, vqs, callbacks, names);
+
+        if (rc)
+                return rc;
+
+        /* Select and activate all queues. Has to be done last: once we do
+         * this, there's no way to go back except reset.
+         */
+        list_for_each_entry(vq, &vdev->vqs, list) {
+                iowrite16(vq->index, &vp_dev->common->queue_select);
+                iowrite8(1, &vp_dev->common->queue_enable);
+        }
+
+        return 0;
+}
+
+static void del_vq(struct virtio_pci_vq_info *info)
+{
+        struct virtqueue *vq = info->vq;
+        struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
+
+        iowrite16(vq->index, &vp_dev->common->queue_select);
+
+        if (vp_dev->msix_enabled) {
+                iowrite16(VIRTIO_MSI_NO_VECTOR,
+                          &vp_dev->common->queue_msix_vector);
+                /* Flush the write out to device */
+                ioread16(&vp_dev->common->queue_msix_vector);
+        }
+
+        pci_iounmap(vp_dev->pci_dev, (void __force __iomem *)vq->priv);
+
+        vring_del_virtqueue(vq);
+
+        free_pages_exact(info->queue, vring_pci_size(info->num));
+}
+
+static const struct virtio_config_ops virtio_pci_config_ops = {
+        .get            = vp_get,
+        .set            = vp_set,
+        .generation     = vp_generation,
+        .get_status     = vp_get_status,
+        .set_status     = vp_set_status,
+        .reset          = vp_reset,
+        .find_vqs       = vp_modern_find_vqs,
+        .del_vqs        = vp_del_vqs,
+        .get_features   = vp_get_features,
+        .finalize_features = vp_finalize_features,
+        .bus_name       = vp_bus_name,
+        .set_vq_affinity = vp_set_vq_affinity,
+};
+
+/**
+ * virtio_pci_find_capability - walk capabilities to find device info.
+ * @dev: the pci device
+ * @cfg_type: the VIRTIO_PCI_CAP_* value we seek
+ * @ioresource_types: IORESOURCE_MEM and/or IORESOURCE_IO.
+ *
+ * Returns offset of the capability, or 0.
+ */
+static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type,
+                                             u32 ioresource_types)
+{
+        int pos;
+
+        for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
+             pos > 0;
+             pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
+                u8 type, bar;
+                pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
+                                                         cfg_type),
+                                     &type);
+                pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
+                                                         bar),
+                                     &bar);
+
+                /* Ignore structures with reserved BAR values */
+                if (bar > 0x5)
+                        continue;
+
+                if (type == cfg_type) {
+                        if (pci_resource_len(dev, bar) &&
+                            pci_resource_flags(dev, bar) & ioresource_types)
+                                return pos;
+                }
+        }
+        return 0;
+}
+
+static void virtio_pci_release_dev(struct device *_d)
+{
+        struct virtio_device *vdev = dev_to_virtio(_d);
+        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+
+        kfree(vp_dev);
+}
+
+/* TODO: validate the ABI statically. */
+static inline void check_offsets(void)
+{
+}
+
+/* the PCI probing function */
+int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
+{
+        struct pci_dev *pci_dev = vp_dev->pci_dev;
+        int err, common, isr, notify, device;
+        u32 notify_length;
+
+        check_offsets();
+
+        /* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */
+        if (pci_dev->device < 0x1000 || pci_dev->device > 0x107f)
+                return -ENODEV;
+
+        if (pci_dev->device < 0x1040) {
+                /* Transitional devices: use the PCI subsystem device id as
+                 * virtio device id, same as legacy driver always did.
+                 */
+                vp_dev->vdev.id.device = pci_dev->subsystem_device;
+        } else {
+                /* Modern devices: simply use PCI device id, but start from 0x1040. */
+                vp_dev->vdev.id.device = pci_dev->device - 0x1040;
+        }
+        vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
+
+        if (virtio_device_is_legacy_only(vp_dev->vdev.id))
+                return -ENODEV;
+
+        /* check for a common config: if not, use legacy mode (bar 0). */
+        common = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG,
+                                            IORESOURCE_IO | IORESOURCE_MEM);
+        if (!common) {
+                dev_info(&pci_dev->dev,
+                         "virtio_pci: leaving for legacy driver\n");
+                return -ENODEV;
+        }
+
+        /* If common is there, these should be too... */
+        isr = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_ISR_CFG,
+                                         IORESOURCE_IO | IORESOURCE_MEM);
+        notify = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_NOTIFY_CFG,
+                                            IORESOURCE_IO | IORESOURCE_MEM);
+        if (!isr || !notify) {
+                dev_err(&pci_dev->dev,
+                        "virtio_pci: missing capabilities %i/%i/%i\n",
+                        common, isr, notify);
+                return -EINVAL;
+        }
+
+        /* Device capability is only mandatory for devices that have
+         * device-specific configuration.
+         */
+        device = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_DEVICE_CFG,
+                                            IORESOURCE_IO | IORESOURCE_MEM);
+
+        err = -EINVAL;
+        vp_dev->common = map_capability(pci_dev, common,
+                                        sizeof(struct virtio_pci_common_cfg), 4,
+                                        0, sizeof(struct virtio_pci_common_cfg),
+                                        NULL);
+        if (!vp_dev->common)
+                goto err_map_common;
+        vp_dev->isr = map_capability(pci_dev, isr, sizeof(u8), 1,
+                                     0, 1,
+                                     NULL);
+        if (!vp_dev->isr)
+                goto err_map_isr;
+
+        /* Read notify_off_multiplier from config space. */
+        pci_read_config_dword(pci_dev,
+                              notify + offsetof(struct virtio_pci_notify_cap,
+                                                notify_off_multiplier),
+                              &vp_dev->notify_offset_multiplier);
+        /* Read notify length from config space. */
+        pci_read_config_dword(pci_dev,
+                              notify + offsetof(struct virtio_pci_notify_cap,
+                                                cap.length),
+                              &notify_length);
+
+        vp_dev->notify_map_cap = notify;
+
+        /* Again, we don't know how much we should map, but PAGE_SIZE
+         * is more than enough for all existing devices.
+         */
+        if (device) {
+                vp_dev->device = map_capability(pci_dev, device, 0, 4,
+                                                0, PAGE_SIZE,
+                                                &vp_dev->device_len);
+                if (!vp_dev->device)
+                        goto err_map_device;
+        }
+
+        vp_dev->vdev.config = &virtio_pci_config_ops;
+
+        vp_dev->config_vector = vp_config_vector;
+        vp_dev->setup_vq = setup_vq;
+        vp_dev->del_vq = del_vq;
+
+        return 0;
+
+err_map_device:
+        pci_iounmap(pci_dev, vp_dev->isr);
+err_map_isr:
+        pci_iounmap(pci_dev, vp_dev->common);
+err_map_common:
+        return err;
+}
+
+void virtio_pci_modern_remove(struct virtio_pci_device *vp_dev)
+{
+        struct pci_dev *pci_dev = vp_dev->pci_dev;
+
+        if (vp_dev->device)
+                pci_iounmap(pci_dev, vp_dev->device);
+        pci_iounmap(pci_dev, vp_dev->isr);
+        pci_iounmap(pci_dev, vp_dev->common);
+}