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SubjectRe: [PATCH v1 01/16] virtio: Validate queue pfn for 32bit transports
On Tue, Jan 09, 2018 at 07:03:56PM +0000, Suzuki K Poulose wrote:
> virtio-mmio using virtio-v1 and virtio legacy pci use 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@linaro.org>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

Could you guys please work on virtio 1 support in
for virtio mmio in qemu though?
It's not a lot of code.

> ---
> drivers/virtio/virtio_mmio.c | 19 ++++++++++++++++---
> drivers/virtio/virtio_pci_legacy.c | 11 +++++++++--
> 2 files changed, 25 insertions(+), 5 deletions(-)

I'd rather see this as 2 patches.

> diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> index a9192fe4f345..47109baf37f7 100644
> --- a/drivers/virtio/virtio_mmio.c
> +++ b/drivers/virtio/virtio_mmio.c
> @@ -358,6 +358,7 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
> struct virtqueue *vq;
> unsigned long flags;
> unsigned int num;
> + u64 addr;
> int err;
>
> if (!name)
> @@ -394,16 +395,26 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
> goto error_new_virtqueue;
> }
>
> + addr = virtqueue_get_desc_addr(vq);
> + /*
> + * virtio-mmio v1 uses a 32bit QUEUE PFN. If we have something that
> + * doesn't fit in 32bit, fail the setup rather than pretending to
> + * be successful.
> + */
> + if (vm_dev->version == 1 && (addr >> (PAGE_SHIFT + 32))) {
> + dev_err(&vdev->dev, "virtio-mmio: queue address too large\n");
> + err = -ENOMEM;
> + goto error_bad_pfn;
> + }
> +

Can you please move this below to where it's actually used?

> /* Activate the queue */
> writel(virtqueue_get_vring_size(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
> if (vm_dev->version == 1) {
> writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
> - writel(virtqueue_get_desc_addr(vq) >> PAGE_SHIFT,
> + writel(addr >> PAGE_SHIFT,
> vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
> } else {
> - u64 addr;
>
> - addr = virtqueue_get_desc_addr(vq);
> writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_LOW);
> writel((u32)(addr >> 32),
> vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_HIGH);
> @@ -430,6 +441,8 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
>
> return vq;
>
> +error_bad_pfn:
> + vring_del_virtqueue(vq);
> error_new_virtqueue:
> if (vm_dev->version == 1) {
> writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
> diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
> index 2780886e8ba3..099d2cfb47b3 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;
> + goto out_deactivate;

You never set up the address, it's cleaner to add another target
and not reset it.

> + }
> +
> /* 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);
>
> vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
>
> --
> 2.13.6

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