Messages in this thread | | | Date | Tue, 27 Mar 2018 17:07:27 +0300 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH v2 01/17] virtio: mmio-v1: Validate queue PFN |
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On Tue, Mar 27, 2018 at 02:15:11PM +0100, Suzuki K Poulose wrote: > virtio-mmio with virtio-v1 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>
OK - seems harmless so I will queue this. But I really think effort should be spent on adding v1.0 support in QEMU.
> --- > drivers/virtio/virtio_mmio.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c > index 67763d3..b2f9b5c 100644 > --- a/drivers/virtio/virtio_mmio.c > +++ b/drivers/virtio/virtio_mmio.c > @@ -397,9 +397,21 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index, > /* Activate the queue */ > writel(virtqueue_get_vring_size(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NUM); > if (vm_dev->version == 1) { > + u64 q_pfn = virtqueue_get_desc_addr(vq) >> PAGE_SHIFT; > + > + /* > + * 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 (q_pfn >> 32) { > + dev_err(&vdev->dev, "virtio-mmio: queue address too large\n"); > + err = -ENOMEM; > + goto error_bad_pfn; > + } > + > writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN); > - writel(virtqueue_get_desc_addr(vq) >> PAGE_SHIFT, > - vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); > + writel(q_pfn, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); > } else { > u64 addr; > > @@ -430,6 +442,8 @@ 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); > -- > 2.7.4
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