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UPSTREAM: virtio_mmio: Restore guest page size on resume

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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>
(cherry picked from commit e0c2ce8217)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I8dc514a699d9fbc4a209ef9523e3bc25dbe6a3d5
This commit is contained in:
Stephan Gerhold
2022-06-21 13:06:21 +02:00
committed by Treehugger Robot
parent f94739ce6c
commit f9cd6692e7
1 changed files with 3 additions and 0 deletions
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3
drivers/virtio/virtio_mmio.c
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@@ -569,6 +569,9 @@ 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);
}