On 13/07/18 01:36, Michael S. Tsirkin wrote:

On Tue, Mar 27, 2018 at 05:11:04PM +0300, Michael S. Tsirkin wrote:

quoted

On Tue, Mar 27, 2018 at 02:15:12PM +0100, Suzuki K Poulose wrote:

quoted

Legacy PCI over virtio uses a 32bit PFN for the queue. If the
queue pfn is too large to fit in 32bits, which we could hit on
arm64 systems with 52bit physical addresses (even with 64K page
size), we simply miss out a proper link to the other side of
the queue.

Add a check to validate the PFN, rather than silently breaking
the devices.

Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Marc Zyngier <redacted>
Cc: Christoffer Dall <cdall@kernel.org>
Cc: Peter Maydel <redacted>
Cc: Jean-Philippe Brucker <redacted>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
  drivers/virtio/virtio_pci_legacy.c | 12 ++++++++++--
  1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
index 2780886..4b84a75 100644
--- a/drivers/virtio/virtio_pci_legacy.c
+++ b/drivers/virtio/virtio_pci_legacy.c

@@ -122,6 +122,7 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
  	struct virtqueue *vq;
  	u16 num;
  	int err;
+	u64 q_pfn;
  
  	/* Select the queue we're interested in */
  	iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);

@@ -141,9 +142,15 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
  	if (!vq)
  		return ERR_PTR(-ENOMEM);
  
+	q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;
+	if (q_pfn >> 32) {
+		dev_err(&vp_dev->pci_dev->dev, "virtio-pci queue PFN too large\n");
+		err = -ENOMEM;

ENOMEM seems wrong here. E2BIG?

quoted

+		goto out_del_vq;
+	}
+
  	/* activate the queue */
-	iowrite32(virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT,
-		  vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
+	iowrite32((u32)q_pfn, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);

Is the cast really necessary here?

quoted

  
  	vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
  

@@ -160,6 +167,7 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
  
  out_deactivate:
  	iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
+out_del_vq:
  	vring_del_virtqueue(vq);
  	return ERR_PTR(err);
  }

-- 
2.7.4

Michael,

Ping are you going to address and repost, or should I drop this?

This was addressed and reposted as v3, which needs a minor update to the
error message as mentioned here [0]. I will post the fixed version today.

[0] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-July/588398.html

Thanks
Suzuki