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| author | Stefano Garzarella | 2020-09-21 14:25:03 +0200 |
|---|---|---|
| committer | Michael S. Tsirkin | 2020-09-29 08:15:24 +0200 |
| commit | d55f518248f263bb8d0852f98e47102ea09d4f89 (patch) | |
| tree | a1fd5d8d6310b739ce7bdb0d94be918dadd460f8 /hw/virtio | |
| parent | configure: Fix build dependencies with vhost-vdpa. (diff) | |
| download | qemu-d55f518248f263bb8d0852f98e47102ea09d4f89.tar.gz qemu-d55f518248f263bb8d0852f98e47102ea09d4f89.tar.xz qemu-d55f518248f263bb8d0852f98e47102ea09d4f89.zip | |
virtio: skip legacy support check on machine types less than 5.1
Commit 9b3a35ec82 ("virtio: verify that legacy support is not accidentally
on") added a check that returns an error if legacy support is on, but the
device does not support legacy.
Unfortunately some devices were wrongly declared legacy capable even if
they were not (e.g vhost-vsock).
To avoid migration issues, we add a virtio-device property
(x-disable-legacy-check) to skip the legacy error, printing a warning
instead, for machine types < 5.1.
Cc: qemu-stable@nongnu.org
Fixes: 9b3a35ec82 ("virtio: verify that legacy support is not accidentally on")
Suggested-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Suggested-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20200921122506.82515-2-sgarzare@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw/virtio')
| -rw-r--r-- | hw/virtio/virtio-pci.c | 14 | ||||
| -rw-r--r-- | hw/virtio/virtio.c | 7 |
2 files changed, 19 insertions, 2 deletions
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c index 02790e3237..36524a5728 100644 --- a/hw/virtio/virtio-pci.c +++ b/hw/virtio/virtio-pci.c @@ -1597,8 +1597,18 @@ static void virtio_pci_device_plugged(DeviceState *d, Error **errp) if (legacy) { if (!virtio_legacy_allowed(vdev)) { - error_setg(errp, "device is modern-only, use disable-legacy=on"); - return; + /* + * To avoid migration issues, we allow legacy mode when legacy + * check is disabled in the old machine types (< 5.1). + */ + if (virtio_legacy_check_disabled(vdev)) { + warn_report("device is modern-only, but for backward " + "compatibility legacy is allowed"); + } else { + error_setg(errp, + "device is modern-only, use disable-legacy=on"); + return; + } } if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) { error_setg(errp, "VIRTIO_F_IOMMU_PLATFORM was supported by" diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 3a3d012d9f..a2edb4f386 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -3304,6 +3304,11 @@ bool virtio_legacy_allowed(VirtIODevice *vdev) } } +bool virtio_legacy_check_disabled(VirtIODevice *vdev) +{ + return vdev->disable_legacy_check; +} + hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n) { return vdev->vq[n].vring.desc; @@ -3713,6 +3718,8 @@ static Property virtio_properties[] = { DEFINE_VIRTIO_COMMON_FEATURES(VirtIODevice, host_features), DEFINE_PROP_BOOL("use-started", VirtIODevice, use_started, true), DEFINE_PROP_BOOL("use-disabled-flag", VirtIODevice, use_disabled_flag, true), + DEFINE_PROP_BOOL("x-disable-legacy-check", VirtIODevice, + disable_legacy_check, false), DEFINE_PROP_END_OF_LIST(), }; |