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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>,
	virtualization@lists.linux-foundation.org,
	Stephan Gerhold <stephan.gerhold@kernkonzept.com>,
	"Michael S . Tsirkin" <mst@redhat.com>
Subject: [PATCH AUTOSEL 5.15 06/18] virtio_mmio: Restore guest page size on resume
Date: Wed,  6 Jul 2022 11:31:41 -0400	[thread overview]
Message-ID: <20220706153153.1598076-6-sashal@kernel.org> (raw)
In-Reply-To: <20220706153153.1598076-1-sashal@kernel.org>

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 7522832529dd..fe696aafaed8 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);
 }
 
-- 
2.35.1

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      parent reply	other threads:[~2022-07-06 15:32 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20220706153153.1598076-1-sashal@kernel.org>
2022-07-06 15:31 ` [PATCH AUTOSEL 5.15 03/18] vdpa/mlx5: Initialize CVQ vringh only once Sasha Levin
2022-07-06 15:31 ` [PATCH AUTOSEL 5.15 04/18] vduse: Tie vduse mgmtdev and its device Sasha Levin
2022-07-06 15:31 ` [PATCH AUTOSEL 5.15 05/18] virtio_mmio: Add missing PM calls to freeze/restore Sasha Levin
2022-07-06 15:31 ` Sasha Levin [this message]

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