include/hw/virtio/virtio.h | 1 + hw/core/machine.c | 1 + hw/virtio/virtio.c | 18 ++++++++++++++++-- 3 files changed, 18 insertions(+), 2 deletions(-)
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 is not legacy.
Unfortunately some devices were wrongly declared legacy even if they
were not (e.g vhost-vsock).
To avoid migration issues, we disable this error for machine types < 5.1,
but we print a warning.
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 <cornelia.huck@de.ibm.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
include/hw/virtio/virtio.h | 1 +
hw/core/machine.c | 1 +
hw/virtio/virtio.c | 18 ++++++++++++++++--
3 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 807280451b..ed7cee348b 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -103,6 +103,7 @@ 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;
diff --git a/hw/core/machine.c b/hw/core/machine.c
index ea26d61237..b686eab798 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/virtio/virtio.c b/hw/virtio/virtio.c
index e983025217..30ccc43b8c 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -3287,6 +3287,8 @@ void virtio_init(VirtIODevice *vdev, const char *name,
*/
bool virtio_legacy_allowed(VirtIODevice *vdev)
{
+ bool ret = false;
+
switch (vdev->device_id) {
case VIRTIO_ID_NET:
case VIRTIO_ID_BLOCK:
@@ -3298,10 +3300,20 @@ bool virtio_legacy_allowed(VirtIODevice *vdev)
case VIRTIO_ID_9P:
case VIRTIO_ID_RPROC_SERIAL:
case VIRTIO_ID_CAIF:
+ ret = true;
+ }
+
+ /*
+ * For backward compatibility, we allow legacy mode with old machine types
+ * to get the migration working.
+ */
+ if (!ret && vdev->disable_legacy_check) {
+ warn_report("device is modern-only, but for backward compatibility "
+ "legacy is allowed");
return true;
- default:
- return false;
}
+
+ return ret;
}
hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n)
@@ -3713,6 +3725,8 @@ 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(),
};
--
2.26.2
On Tue, Sep 15, 2020 at 03:00:00PM +0200, Stefano Garzarella wrote: > 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 is not legacy. > > Unfortunately some devices were wrongly declared legacy even if they > were not (e.g vhost-vsock). > > To avoid migration issues, we disable this error for machine types < 5.1, > but we print a warning. > > 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 <cornelia.huck@de.ibm.com> Wrong Cornelia's e-mail address, I sent a v2! Sorry, Stefano > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> > --- > include/hw/virtio/virtio.h | 1 + > hw/core/machine.c | 1 + > hw/virtio/virtio.c | 18 ++++++++++++++++-- > 3 files changed, 18 insertions(+), 2 deletions(-) > > diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h > index 807280451b..ed7cee348b 100644 > --- a/include/hw/virtio/virtio.h > +++ b/include/hw/virtio/virtio.h > @@ -103,6 +103,7 @@ 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; > diff --git a/hw/core/machine.c b/hw/core/machine.c > index ea26d61237..b686eab798 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/virtio/virtio.c b/hw/virtio/virtio.c > index e983025217..30ccc43b8c 100644 > --- a/hw/virtio/virtio.c > +++ b/hw/virtio/virtio.c > @@ -3287,6 +3287,8 @@ void virtio_init(VirtIODevice *vdev, const char *name, > */ > bool virtio_legacy_allowed(VirtIODevice *vdev) > { > + bool ret = false; > + > switch (vdev->device_id) { > case VIRTIO_ID_NET: > case VIRTIO_ID_BLOCK: > @@ -3298,10 +3300,20 @@ bool virtio_legacy_allowed(VirtIODevice *vdev) > case VIRTIO_ID_9P: > case VIRTIO_ID_RPROC_SERIAL: > case VIRTIO_ID_CAIF: > + ret = true; > + } > + > + /* > + * For backward compatibility, we allow legacy mode with old machine types > + * to get the migration working. > + */ > + if (!ret && vdev->disable_legacy_check) { > + warn_report("device is modern-only, but for backward compatibility " > + "legacy is allowed"); > return true; > - default: > - return false; > } > + > + return ret; > } > > hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n) > @@ -3713,6 +3725,8 @@ 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(), > }; > > -- > 2.26.2 > >
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