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SubjectRe: [PATCH v2 02/17] virtio: pci-legacy: Validate queue pfn
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On 13/07/18 01:36, Michael S. Tsirkin wrote:
> On Tue, Mar 27, 2018 at 05:11:04PM +0300, Michael S. Tsirkin wrote:
>> On Tue, Mar 27, 2018 at 02:15:12PM +0100, Suzuki K Poulose wrote:
>>> 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 <marc.zyngier@arm.com>
>>> Cc: Christoffer Dall <cdall@kernel.org>
>>> Cc: Peter Maydel <peter.maydell@linaro.org>
>>> Cc: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
>>> 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?
>>
>>> + 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?
>>
>>>
>>> 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
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