Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 831 insertions, 0 deletions

diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
new file mode 100644
index 000000000..3d6ae5a5e
--- /dev/null
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -0,0 +1,831 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * 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>
+ */
+
+#include <linux/delay.h>
+#define VIRTIO_PCI_NO_LEGACY
+#define VIRTIO_RING_NO_LEGACY
+#include "virtio_pci_common.h"
+
+/*
+ * Type-safe wrappers for io accesses.
+ * Use these to enforce at compile time the following spec requirement:
+ *
+ * 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.
+ */
+static inline u8 vp_ioread8(const u8 __iomem *addr)
+{
+	return ioread8(addr);
+}
+static inline u16 vp_ioread16 (const __le16 __iomem *addr)
+{
+	return ioread16(addr);
+}
+
+static inline u32 vp_ioread32(const __le32 __iomem *addr)
+{
+	return ioread32(addr);
+}
+
+static inline void vp_iowrite8(u8 value, u8 __iomem *addr)
+{
+	iowrite8(value, addr);
+}
+
+static inline void vp_iowrite16(u16 value, __le16 __iomem *addr)
+{
+	iowrite16(value, addr);
+}
+
+static inline void vp_iowrite32(u32 value, __le32 __iomem *addr)
+{
+	iowrite32(value, addr);
+}
+
+static void vp_iowrite64_twopart(u64 val,
+				 __le32 __iomem *lo, __le32 __iomem *hi)
+{
+	vp_iowrite32((u32)val, lo);
+	vp_iowrite32(val >> 32, hi);
+}
+
+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;
+}
+
+/* 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;
+
+	vp_iowrite32(0, &vp_dev->common->device_feature_select);
+	features = vp_ioread32(&vp_dev->common->device_feature);
+	vp_iowrite32(1, &vp_dev->common->device_feature_select);
+	features |= ((u64)vp_ioread32(&vp_dev->common->device_feature) << 32);
+
+	return features;
+}
+
+static void vp_transport_features(struct virtio_device *vdev, u64 features)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	struct pci_dev *pci_dev = vp_dev->pci_dev;
+
+	if ((features & BIT_ULL(VIRTIO_F_SR_IOV)) &&
+			pci_find_ext_capability(pci_dev, PCI_EXT_CAP_ID_SRIOV))
+		__virtio_set_bit(vdev, VIRTIO_F_SR_IOV);
+}
+
+/* virtio config->finalize_features() implementation */
+static int vp_finalize_features(struct virtio_device *vdev)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	u64 features = vdev->features;
+
+	/* Give virtio_ring a chance to accept features. */
+	vring_transport_features(vdev);
+
+	/* Give virtio_pci a chance to accept features. */
+	vp_transport_features(vdev, features);
+
+	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;
+	}
+
+	vp_iowrite32(0, &vp_dev->common->guest_feature_select);
+	vp_iowrite32((u32)vdev->features, &vp_dev->common->guest_feature);
+	vp_iowrite32(1, &vp_dev->common->guest_feature_select);
+	vp_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 vp_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 vp_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);
+	vp_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. */
+	vp_iowrite8(0, &vp_dev->common->device_status);
+	/* After writing 0 to device_status, the driver MUST wait for a read of
+	 * device_status to return 0 before reinitializing the device.
+	 * This will flush out the status write, and flush in device writes,
+	 * including MSI-X interrupts, if any.
+	 */
+	while (vp_ioread8(&vp_dev->common->device_status))
+		msleep(1);
+	/* 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 */
+	vp_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 vp_ioread16(&vp_dev->common->msix_config);
+}
+
+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,
+				  bool ctx,
+				  u16 msix_vec)
+{
+	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
+	struct virtqueue *vq;
+	u16 num, off;
+	int err;
+
+	if (index >= vp_ioread16(&cfg->num_queues))
+		return ERR_PTR(-ENOENT);
+
+	/* Select the queue we're interested in */
+	vp_iowrite16(index, &cfg->queue_select);
+
+	/* Check if queue is either not available or already active. */
+	num = vp_ioread16(&cfg->queue_size);
+	if (!num || vp_ioread16(&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 = vp_ioread16(&cfg->queue_notify_off);
+
+	info->msix_vector = msix_vec;
+
+	/* create the vring */
+	vq = vring_create_virtqueue(index, num,
+				    SMP_CACHE_BYTES, &vp_dev->vdev,
+				    true, true, ctx,
+				    vp_notify, callback, name);
+	if (!vq)
+		return ERR_PTR(-ENOMEM);
+
+	/* activate the queue */
+	vp_iowrite16(virtqueue_get_vring_size(vq), &cfg->queue_size);
+	vp_iowrite64_twopart(virtqueue_get_desc_addr(vq),
+			     &cfg->queue_desc_lo, &cfg->queue_desc_hi);
+	vp_iowrite64_twopart(virtqueue_get_avail_addr(vq),
+			     &cfg->queue_avail_lo, &cfg->queue_avail_hi);
+	vp_iowrite64_twopart(virtqueue_get_used_addr(vq),
+			     &cfg->queue_used_lo, &cfg->queue_used_hi);
+
+	if (vp_dev->notify_base) {
+		/* offset should not wrap */
+		if ((u64)off * vp_dev->notify_offset_multiplier + 2
+		    > vp_dev->notify_len) {
+			dev_warn(&vp_dev->pci_dev->dev,
+				 "bad notification offset %u (x %u) "
+				 "for queue %u > %zd",
+				 off, vp_dev->notify_offset_multiplier,
+				 index, vp_dev->notify_len);
+			err = -EINVAL;
+			goto err_map_notify;
+		}
+		vq->priv = (void __force *)vp_dev->notify_base +
+			off * vp_dev->notify_offset_multiplier;
+	} else {
+		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) {
+		vp_iowrite16(msix_vec, &cfg->queue_msix_vector);
+		msix_vec = vp_ioread16(&cfg->queue_msix_vector);
+		if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
+			err = -EBUSY;
+			goto err_assign_vector;
+		}
+	}
+
+	return vq;
+
+err_assign_vector:
+	if (!vp_dev->notify_base)
+		pci_iounmap(vp_dev->pci_dev, (void __iomem __force *)vq->priv);
+err_map_notify:
+	vring_del_virtqueue(vq);
+	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 * const names[], const bool *ctx,
+			      struct irq_affinity *desc)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	struct virtqueue *vq;
+	int rc = vp_find_vqs(vdev, nvqs, vqs, callbacks, names, ctx, desc);
+
+	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) {
+		vp_iowrite16(vq->index, &vp_dev->common->queue_select);
+		vp_iowrite16(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);
+
+	vp_iowrite16(vq->index, &vp_dev->common->queue_select);
+
+	if (vp_dev->msix_enabled) {
+		vp_iowrite16(VIRTIO_MSI_NO_VECTOR,
+			     &vp_dev->common->queue_msix_vector);
+		/* Flush the write out to device */
+		vp_ioread16(&vp_dev->common->queue_msix_vector);
+	}
+
+	if (!vp_dev->notify_base)
+		pci_iounmap(vp_dev->pci_dev, (void __force __iomem *)vq->priv);
+
+	vring_del_virtqueue(vq);
+}
+
+static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
+				   u8 *bar, u64 *offset, u64 *len)
+{
+	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, cap_len, id;
+		u32 tmp32;
+		u64 res_offset, res_length;
+
+		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
+							 cfg_type), &type);
+		if (type != VIRTIO_PCI_CAP_SHARED_MEMORY_CFG)
+			continue;
+
+		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
+							 cap_len), &cap_len);
+		if (cap_len != sizeof(struct virtio_pci_cap64)) {
+			dev_err(&dev->dev, "%s: shm cap with bad size offset:"
+				" %d size: %d\n", __func__, pos, cap_len);
+			continue;
+		}
+
+		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
+							 id), &id);
+		if (id != required_id)
+			continue;
+
+		/* Type, and ID match, looks good */
+		pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
+							 bar), bar);
+
+		/* Read the lower 32bit of length and offset */
+		pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap,
+							  offset), &tmp32);
+		res_offset = tmp32;
+		pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap,
+							  length), &tmp32);
+		res_length = tmp32;
+
+		/* and now the top half */
+		pci_read_config_dword(dev,
+				      pos + offsetof(struct virtio_pci_cap64,
+						     offset_hi), &tmp32);
+		res_offset |= ((u64)tmp32) << 32;
+		pci_read_config_dword(dev,
+				      pos + offsetof(struct virtio_pci_cap64,
+						     length_hi), &tmp32);
+		res_length |= ((u64)tmp32) << 32;
+
+		*offset = res_offset;
+		*len = res_length;
+
+		return pos;
+	}
+	return 0;
+}
+
+static bool vp_get_shm_region(struct virtio_device *vdev,
+			      struct virtio_shm_region *region, u8 id)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	struct pci_dev *pci_dev = vp_dev->pci_dev;
+	u8 bar;
+	u64 offset, len;
+	phys_addr_t phys_addr;
+	size_t bar_len;
+
+	if (!virtio_pci_find_shm_cap(pci_dev, id, &bar, &offset, &len))
+		return false;
+
+	phys_addr = pci_resource_start(pci_dev, bar);
+	bar_len = pci_resource_len(pci_dev, bar);
+
+	if ((offset + len) < offset) {
+		dev_err(&pci_dev->dev, "%s: cap offset+len overflow detected\n",
+			__func__);
+		return false;
+	}
+
+	if (offset + len > bar_len) {
+		dev_err(&pci_dev->dev, "%s: bar shorter than cap offset+len\n",
+			__func__);
+		return false;
+	}
+
+	region->len = len;
+	region->addr = (u64) phys_addr + offset;
+
+	return true;
+}
+
+static const struct virtio_config_ops virtio_pci_config_nodev_ops = {
+	.get		= NULL,
+	.set		= NULL,
+	.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,
+	.get_vq_affinity = vp_get_vq_affinity,
+	.get_shm_region  = vp_get_shm_region,
+};
+
+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,
+	.get_vq_affinity = vp_get_vq_affinity,
+	.get_shm_region  = vp_get_shm_region,
+};
+
+/**
+ * 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.
+ * @bars: the bitmask of BARs
+ *
+ * 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 *bars)
+{
+	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) {
+				*bars |= (1 << bar);
+				return pos;
+			}
+		}
+	}
+	return 0;
+}
+
+/* This is part of the ABI.  Don't screw with it. */
+static inline void check_offsets(void)
+{
+	/* Note: disk space was harmed in compilation of this function. */
+	BUILD_BUG_ON(VIRTIO_PCI_CAP_VNDR !=
+		     offsetof(struct virtio_pci_cap, cap_vndr));
+	BUILD_BUG_ON(VIRTIO_PCI_CAP_NEXT !=
+		     offsetof(struct virtio_pci_cap, cap_next));
+	BUILD_BUG_ON(VIRTIO_PCI_CAP_LEN !=
+		     offsetof(struct virtio_pci_cap, cap_len));
+	BUILD_BUG_ON(VIRTIO_PCI_CAP_CFG_TYPE !=
+		     offsetof(struct virtio_pci_cap, cfg_type));
+	BUILD_BUG_ON(VIRTIO_PCI_CAP_BAR !=
+		     offsetof(struct virtio_pci_cap, bar));
+	BUILD_BUG_ON(VIRTIO_PCI_CAP_OFFSET !=
+		     offsetof(struct virtio_pci_cap, offset));
+	BUILD_BUG_ON(VIRTIO_PCI_CAP_LENGTH !=
+		     offsetof(struct virtio_pci_cap, length));
+	BUILD_BUG_ON(VIRTIO_PCI_NOTIFY_CAP_MULT !=
+		     offsetof(struct virtio_pci_notify_cap,
+			      notify_off_multiplier));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DFSELECT !=
+		     offsetof(struct virtio_pci_common_cfg,
+			      device_feature_select));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_DF !=
+		     offsetof(struct virtio_pci_common_cfg, device_feature));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GFSELECT !=
+		     offsetof(struct virtio_pci_common_cfg,
+			      guest_feature_select));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_GF !=
+		     offsetof(struct virtio_pci_common_cfg, guest_feature));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_MSIX !=
+		     offsetof(struct virtio_pci_common_cfg, msix_config));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_NUMQ !=
+		     offsetof(struct virtio_pci_common_cfg, num_queues));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_STATUS !=
+		     offsetof(struct virtio_pci_common_cfg, device_status));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_CFGGENERATION !=
+		     offsetof(struct virtio_pci_common_cfg, config_generation));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SELECT !=
+		     offsetof(struct virtio_pci_common_cfg, queue_select));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_SIZE !=
+		     offsetof(struct virtio_pci_common_cfg, queue_size));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_MSIX !=
+		     offsetof(struct virtio_pci_common_cfg, queue_msix_vector));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_ENABLE !=
+		     offsetof(struct virtio_pci_common_cfg, queue_enable));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_NOFF !=
+		     offsetof(struct virtio_pci_common_cfg, queue_notify_off));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCLO !=
+		     offsetof(struct virtio_pci_common_cfg, queue_desc_lo));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_DESCHI !=
+		     offsetof(struct virtio_pci_common_cfg, queue_desc_hi));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILLO !=
+		     offsetof(struct virtio_pci_common_cfg, queue_avail_lo));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_AVAILHI !=
+		     offsetof(struct virtio_pci_common_cfg, queue_avail_hi));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDLO !=
+		     offsetof(struct virtio_pci_common_cfg, queue_used_lo));
+	BUILD_BUG_ON(VIRTIO_PCI_COMMON_Q_USEDHI !=
+		     offsetof(struct virtio_pci_common_cfg, queue_used_hi));
+}
+
+/* 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;
+	u32 notify_offset;
+
+	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;
+
+	/* 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,
+					    &vp_dev->modern_bars);
+	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,
+					 &vp_dev->modern_bars);
+	notify = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_NOTIFY_CFG,
+					    IORESOURCE_IO | IORESOURCE_MEM,
+					    &vp_dev->modern_bars);
+	if (!isr || !notify) {
+		dev_err(&pci_dev->dev,
+			"virtio_pci: missing capabilities %i/%i/%i\n",
+			common, isr, notify);
+		return -EINVAL;
+	}
+
+	err = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(64));
+	if (err)
+		err = dma_set_mask_and_coherent(&pci_dev->dev,
+						DMA_BIT_MASK(32));
+	if (err)
+		dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
+
+	/* 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,
+					    &vp_dev->modern_bars);
+
+	err = pci_request_selected_regions(pci_dev, vp_dev->modern_bars,
+					   "virtio-pci-modern");
+	if (err)
+		return err;
+
+	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 and offset from config space. */
+	pci_read_config_dword(pci_dev,
+			      notify + offsetof(struct virtio_pci_notify_cap,
+						cap.length),
+			      &notify_length);
+
+	pci_read_config_dword(pci_dev,
+			      notify + offsetof(struct virtio_pci_notify_cap,
+						cap.offset),
+			      &notify_offset);
+
+	/* We don't know how many VQs we'll map, ahead of the time.
+	 * If notify length is small, map it all now.
+	 * Otherwise, map each VQ individually later.
+	 */
+	if ((u64)notify_length + (notify_offset % PAGE_SIZE) <= PAGE_SIZE) {
+		vp_dev->notify_base = map_capability(pci_dev, notify, 2, 2,
+						     0, notify_length,
+						     &vp_dev->notify_len);
+		if (!vp_dev->notify_base)
+			goto err_map_notify;
+	} else {
+		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;
+	} else {
+		vp_dev->vdev.config = &virtio_pci_config_nodev_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:
+	if (vp_dev->notify_base)
+		pci_iounmap(pci_dev, vp_dev->notify_base);
+err_map_notify:
+	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);
+	if (vp_dev->notify_base)
+		pci_iounmap(pci_dev, vp_dev->notify_base);
+	pci_iounmap(pci_dev, vp_dev->isr);
+	pci_iounmap(pci_dev, vp_dev->common);
+	pci_release_selected_regions(pci_dev, vp_dev->modern_bars);
+}