From: Stephan Gerhold stephan.gerhold@kernkonzept.com
[ Upstream commit e0c2ce8217955537dd5434baeba061f209797119 ]
Virtio devices might lose their state when the VMM is restarted after a suspend to disk (hibernation) cycle. This means that the guest page size register must be restored for the virtio_mmio legacy interface, since otherwise the virtio queues are not functional.
This is particularly problematic for QEMU that currently still defaults to using the legacy interface for virtio_mmio. Write the guest page size register again in virtio_mmio_restore() to make legacy virtio_mmio devices work correctly after hibernation.
Signed-off-by: Stephan Gerhold stephan.gerhold@kernkonzept.com Message-Id: 20220621110621.3638025-3-stephan.gerhold@kernkonzept.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/virtio/virtio_mmio.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c index 7dec1418bf7c..e8ef0c66e558 100644 --- a/drivers/virtio/virtio_mmio.c +++ b/drivers/virtio/virtio_mmio.c @@ -556,6 +556,9 @@ static int virtio_mmio_restore(struct device *dev) { struct virtio_mmio_device *vm_dev = dev_get_drvdata(dev);
+ if (vm_dev->version == 1) + writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE); + return virtio_device_restore(&vm_dev->vdev); }