virtio-pci library: report resource address

Sometimes it might be useful to report the capability physical
address. One example is to report the physical address of the doorbell
in order to be mapped by userspace.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210415073147.19331-7-jasowang@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

2 files changed, 18 insertions, 8 deletions

diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 29607d9bd95c..722ea44e7579 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -224,7 +224,7 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
 				virtqueue_get_avail_addr(vq),
 				virtqueue_get_used_addr(vq));
 
-	vq->priv = vp_modern_map_vq_notify(mdev, index);
+	vq->priv = vp_modern_map_vq_notify(mdev, index, NULL);
 	if (!vq->priv) {
 		err = -ENOMEM;
 		goto err_map_notify;
diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c
index 9c241c9bd920..ae87b3fa8858 100644
--- a/drivers/virtio/virtio_pci_modern_dev.c
+++ b/drivers/virtio/virtio_pci_modern_dev.c
@@ -13,13 +13,14 @@
  * @start: start from the capability
  * @size: map size
  * @len: the length that is actually mapped
+ * @pa: physical address of the capability
  *
  * Returns the io address of for the part of the capability
  */
 static void __iomem *
 vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off,
 			 size_t minlen, u32 align, u32 start, u32 size,
-			 size_t *len)
+			 size_t *len, resource_size_t *pa)
 {
 	struct pci_dev *dev = mdev->pci_dev;
 	u8 bar;
@@ -87,6 +88,9 @@ vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off,
 		dev_err(&dev->dev,
 			"virtio_pci: unable to map virtio %u@%u on bar %i\n",
 			length, offset, bar);
+	else if (pa)
+		*pa = pci_resource_start(dev, bar) + offset;
+
 	return p;
 }
 
@@ -273,12 +277,12 @@ int vp_modern_probe(struct virtio_pci_modern_device *mdev)
 	mdev->common = vp_modern_map_capability(mdev, common,
 				      sizeof(struct virtio_pci_common_cfg), 4,
 				      0, sizeof(struct virtio_pci_common_cfg),
-				      NULL);
+				      NULL, NULL);
 	if (!mdev->common)
 		goto err_map_common;
 	mdev->isr = vp_modern_map_capability(mdev, isr, sizeof(u8), 1,
 					     0, 1,
-					     NULL);
+					     NULL, NULL);
 	if (!mdev->isr)
 		goto err_map_isr;
 
@@ -306,7 +310,8 @@ int vp_modern_probe(struct virtio_pci_modern_device *mdev)
 		mdev->notify_base = vp_modern_map_capability(mdev, notify,
 							     2, 2,
 							     0, notify_length,
-							     &mdev->notify_len);
+							     &mdev->notify_len,
+							     &mdev->notify_pa);
 		if (!mdev->notify_base)
 			goto err_map_notify;
 	} else {
@@ -319,7 +324,8 @@ int vp_modern_probe(struct virtio_pci_modern_device *mdev)
 	if (device) {
 		mdev->device = vp_modern_map_capability(mdev, device, 0, 4,
 							0, PAGE_SIZE,
-							&mdev->device_len);
+							&mdev->device_len,
+							NULL);
 		if (!mdev->device)
 			goto err_map_device;
 	}
@@ -595,11 +601,12 @@ static u16 vp_modern_get_queue_notify_off(struct virtio_pci_modern_device *mdev,
  * specific virtqueue
  * @mdev: the modern virtio-pci device
  * @index: the queue index
+ * @pa: the pointer to the physical address of the nofity area
  *
  * Returns the address of the notification area
  */
 void *vp_modern_map_vq_notify(struct virtio_pci_modern_device *mdev,
-			      u16 index)
+			      u16 index, resource_size_t *pa)
 {
 	u16 off = vp_modern_get_queue_notify_off(mdev, index);
 
@@ -614,13 +621,16 @@ void *vp_modern_map_vq_notify(struct virtio_pci_modern_device *mdev,
 				 index, mdev->notify_len);
 			return NULL;
 		}
+		if (pa)
+			*pa = mdev->notify_pa +
+			      off * mdev->notify_offset_multiplier;
 		return (void __force *)mdev->notify_base +
 			off * mdev->notify_offset_multiplier;
 	} else {
 		return (void __force *)vp_modern_map_capability(mdev,
 				       mdev->notify_map_cap, 2, 2,
 				       off * mdev->notify_offset_multiplier, 2,
-				       NULL);
+				       NULL, pa);
 	}
 }
 EXPORT_SYMBOL_GPL(vp_modern_map_vq_notify);