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109 lines
4.2 KiB
109 lines
4.2 KiB
From c554f8768a18ceba173aedbd582c1cae43a41e2c Mon Sep 17 00:00:00 2001
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From: Thomas Huth <thuth@redhat.com>
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Date: Tue, 18 Jun 2024 14:19:58 +0200
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Subject: [PATCH 1/2] hw/virtio: Fix the de-initialization of vhost-user
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devices
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Thomas Huth <thuth@redhat.com>
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RH-MergeRequest: 255: hw/virtio: Fix the de-initialization of vhost-user devices
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RH-Jira: RHEL-40708
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RH-Acked-by: Cédric Le Goater <clg@redhat.com>
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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RH-Commit: [1/1] c7815a249ec135993f45934cab1c1f2c038b80ea (thuth/qemu-kvm-cs9)
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JIRA: https://issues.redhat.com/browse/RHEL-40708
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The unrealize functions of the various vhost-user devices are
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calling the corresponding vhost_*_set_status() functions with a
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status of 0 to shut down the device correctly.
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Now these vhost_*_set_status() functions all follow this scheme:
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bool should_start = virtio_device_should_start(vdev, status);
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if (vhost_dev_is_started(&vvc->vhost_dev) == should_start) {
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return;
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}
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if (should_start) {
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/* ... do the initialization stuff ... */
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} else {
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/* ... do the cleanup stuff ... */
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}
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The problem here is virtio_device_should_start(vdev, 0) currently
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always returns "true" since it internally only looks at vdev->started
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instead of looking at the "status" parameter. Thus once the device
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got started once, virtio_device_should_start() always returns true
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and thus the vhost_*_set_status() functions return early, without
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ever doing any clean-up when being called with status == 0. This
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causes e.g. problems when trying to hot-plug and hot-unplug a vhost
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user devices multiple times since the de-initialization step is
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completely skipped during the unplug operation.
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This bug has been introduced in commit 9f6bcfd99f ("hw/virtio: move
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vm_running check to virtio_device_started") which replaced
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should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
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with
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should_start = virtio_device_started(vdev, status);
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which later got replaced by virtio_device_should_start(). This blocked
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the possibility to set should_start to false in case the status flag
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VIRTIO_CONFIG_S_DRIVER_OK was not set.
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Fix it by adjusting the virtio_device_should_start() function to
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only consider the status flag instead of vdev->started. Since this
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function is only used in the various vhost_*_set_status() functions
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for exactly the same purpose, it should be fine to fix it in this
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central place there without any risk to change the behavior of other
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code.
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Fixes: 9f6bcfd99f ("hw/virtio: move vm_running check to virtio_device_started")
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Buglink: https://issues.redhat.com/browse/RHEL-40708
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Signed-off-by: Thomas Huth <thuth@redhat.com>
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Message-Id: <20240618121958.88673-1-thuth@redhat.com>
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Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
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Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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(cherry picked from commit d72479b11797c28893e1e3fc565497a9cae5ca16)
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Signed-off-by: Thomas Huth <thuth@redhat.com>
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---
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include/hw/virtio/virtio.h | 8 ++++----
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1 file changed, 4 insertions(+), 4 deletions(-)
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diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
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index 7d5ffdc145..2eafad17b8 100644
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--- a/include/hw/virtio/virtio.h
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+++ b/include/hw/virtio/virtio.h
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@@ -470,9 +470,9 @@ static inline bool virtio_device_started(VirtIODevice *vdev, uint8_t status)
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* @vdev - the VirtIO device
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* @status - the devices status bits
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*
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- * This is similar to virtio_device_started() but also encapsulates a
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- * check on the VM status which would prevent a device starting
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- * anyway.
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+ * This is similar to virtio_device_started() but ignores vdev->started
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+ * and also encapsulates a check on the VM status which would prevent a
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+ * device from starting anyway.
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*/
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static inline bool virtio_device_should_start(VirtIODevice *vdev, uint8_t status)
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{
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@@ -480,7 +480,7 @@ static inline bool virtio_device_should_start(VirtIODevice *vdev, uint8_t status
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return false;
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}
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- return virtio_device_started(vdev, status);
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+ return status & VIRTIO_CONFIG_S_DRIVER_OK;
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}
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static inline void virtio_set_started(VirtIODevice *vdev, bool started)
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--
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2.39.3
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