| Message ID | 20200915130000.78334-1-sgarzare@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | virtio: skip legacy support check on machine types less than 5.1 | expand |
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 > >
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(), };
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(-)