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[PULL v4 16/48] virtio: skip legacy support check on machine types less
From: |
Michael S. Tsirkin |
Subject: |
[PULL v4 16/48] virtio: skip legacy support check on machine types less than 5.1 |
Date: |
Tue, 29 Sep 2020 03:21:34 -0400 |
From: Stefano Garzarella <sgarzare@redhat.com>
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>
---
include/hw/virtio/virtio.h | 2 ++
hw/core/machine.c | 1 +
hw/s390x/virtio-ccw.c | 15 ++++++++++++---
hw/virtio/virtio-pci.c | 14 ++++++++++++--
hw/virtio/virtio.c | 7 +++++++
5 files changed, 34 insertions(+), 5 deletions(-)
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 28cf3b9120..b7ece7a6a8 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -101,6 +101,7 @@ struct VirtIODevice
bool use_started;
bool started;
bool start_on_kick; /* when virtio 1.0 feature has not been negotiated */
+ bool disable_legacy_check;
VMChangeStateEntry *vmstate;
char *bus_name;
uint8_t device_endian;
@@ -394,5 +395,6 @@ static inline bool virtio_device_disabled(VirtIODevice
*vdev)
}
bool virtio_legacy_allowed(VirtIODevice *vdev);
+bool virtio_legacy_check_disabled(VirtIODevice *vdev);
#endif
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 9b02fb2f5e..d7f4a0d259 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -44,6 +44,7 @@ GlobalProperty hw_compat_5_0[] = {
{ "vmport", "x-signal-unsupported-cmd", "off" },
{ "vmport", "x-report-vmx-type", "off" },
{ "vmport", "x-cmds-v2", "off" },
+ { "virtio-device", "x-disable-legacy-check", "true" },
};
const size_t hw_compat_5_0_len = G_N_ELEMENTS(hw_compat_5_0);
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 8d140dc50f..4582e94ae7 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -1122,9 +1122,18 @@ static void virtio_ccw_device_plugged(DeviceState *d,
Error **errp)
}
if (!virtio_ccw_rev_max(dev) && !virtio_legacy_allowed(vdev)) {
- error_setg(errp, "Invalid value of property max_rev "
- "(is %d expected >= 1)", virtio_ccw_rev_max(dev));
- 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 requires revision >= 1, but for backward "
+ "compatibility max_revision=0 is allowed");
+ } else {
+ error_setg(errp, "Invalid value of property max_rev "
+ "(is %d expected >= 1)", virtio_ccw_rev_max(dev));
+ return;
+ }
}
if (virtio_get_num_queues(vdev) > VIRTIO_QUEUE_MAX) {
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(),
};
--
MST
- [PULL v4 04/48] virtio-mem: detach the element from the virtqueue when error occurs, (continued)
- [PULL v4 04/48] virtio-mem: detach the element from the virtqueue when error occurs, Michael S. Tsirkin, 2020/09/29
- [PULL v4 06/48] vhost: recheck dev state in the vhost_migration_log routine, Michael S. Tsirkin, 2020/09/29
- [PULL v4 07/48] vhost: check queue state in the vhost_dev_set_log routine, Michael S. Tsirkin, 2020/09/29
- [PULL v4 08/48] tests/qtest/vhost-user-test: prepare the tests for adding new dev class, Michael S. Tsirkin, 2020/09/29
- [PULL v4 10/48] virtio-iommu: Check gtrees are non null before destroying them, Michael S. Tsirkin, 2020/09/29
- [PULL v4 11/48] virtio-iommu-pci: force virtio version 1, Michael S. Tsirkin, 2020/09/29
- [PULL v4 09/48] cphp: remove deprecated cpu-add command(s), Michael S. Tsirkin, 2020/09/29
- [PULL v4 13/48] util/hexdump: introduce qemu_hexdump_line(), Michael S. Tsirkin, 2020/09/29
- [PULL v4 14/48] vhost-vdpa: add trace-events, Michael S. Tsirkin, 2020/09/29
- [PULL v4 15/48] configure: Fix build dependencies with vhost-vdpa., Michael S. Tsirkin, 2020/09/29
- [PULL v4 16/48] virtio: skip legacy support check on machine types less than 5.1,
Michael S. Tsirkin <=
- [PULL v4 17/48] vhost-vsock-pci: force virtio version 1, Michael S. Tsirkin, 2020/09/29
- [PULL v4 18/48] vhost-user-vsock-pci: force virtio version 1, Michael S. Tsirkin, 2020/09/29
- [PULL v4 19/48] vhost-vsock-ccw: force virtio version 1, Michael S. Tsirkin, 2020/09/29
- [PULL v4 22/48] x86: cpuhp: prevent guest crash on CPU hotplug when broadcast SMI is in use, Michael S. Tsirkin, 2020/09/29
- [PULL v4 21/48] x86: lpc9: let firmware negotiate 'CPU hotplug with SMI' features, Michael S. Tsirkin, 2020/09/29
- [PULL v4 24/48] acpi: add aml_land() and aml_break() primitives, Michael S. Tsirkin, 2020/09/29
- [PULL v4 25/48] tests: acpi: mark to be changed tables in bios-tables-test-allowed-diff, Michael S. Tsirkin, 2020/09/29
- [PULL v4 26/48] x86: ich9: expose "smi_negotiated_features" as a QOM property, Michael S. Tsirkin, 2020/09/29
- [PULL v4 27/48] x86: acpi: introduce AcpiPmInfo::smi_on_cpuhp, Michael S. Tsirkin, 2020/09/29
- [PULL v4 28/48] x86: acpi: introduce the PCI0.SMI0 ACPI device, Michael S. Tsirkin, 2020/09/29