From f9cd6692e7be28fe08f8c413ccfe5a38be3169f5 Mon Sep 17 00:00:00 2001 From: Stephan Gerhold Date: Tue, 21 Jun 2022 13:06:21 +0200 Subject: [PATCH] UPSTREAM: virtio_mmio: Restore guest page size on resume 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 Message-Id: <20220621110621.3638025-3-stephan.gerhold@kernkonzept.com> Signed-off-by: Michael S. Tsirkin (cherry picked from commit e0c2ce8217955537dd5434baeba061f209797119) Signed-off-by: Greg Kroah-Hartman Change-Id: I8dc514a699d9fbc4a209ef9523e3bc25dbe6a3d5 --- 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 980dffd69586..083ff1eb743d 100644 --- a/drivers/virtio/virtio_mmio.c +++ b/drivers/virtio/virtio_mmio.c @@ -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); }