The virtio-gpu 'blob' support was insufficiently validated. Qemu requires a memfd memory backing in order to use udmabuf and enable blob support. Example error: $ virsh start rhel9 error: Failed to start domain 'rhel9' error: internal error: qemu unexpectedly closed the monitor: 2023-07-18T02:33:57.083178Z qemu-kvm: -device {"driver":"virtio-vga","id":"video0","max_outputs":1,"blob":true,"bus":"pcie.0","addr":"0x1"}: cannot enable blob resources without udmabuf Signed-off-by: Jonathon Jongsma <jjongsma(a)redhat.com&gt; --- src/qemu/qemu_validate.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/src/qemu/qemu_validate.c b/src/qemu/qemu_validate.c index 7e09e2c52f..139e6f3d62 100644 --- a/src/qemu/qemu_validate.c +++ b/src/qemu/qemu_validate.c @@ -2598,6 +2598,7 @@ qemuValidateDomainDeviceDefHostdev(const virDomainHostdevDef *hostdev, static int qemuValidateDomainDeviceDefVideo(const virDomainVideoDef *video, + const virDomainDef *def, virQEMUCaps *qemuCaps) { virDomainCapsDeviceVideo videoCaps = { 0 }; @@ -2714,11 +2715,18 @@ qemuValidateDomainDeviceDefVideo(const virDomainVideoDef *video, } if (video->type == VIR_DOMAIN_VIDEO_TYPE_VIRTIO) { - if (video->blob != VIR_TRISTATE_SWITCH_ABSENT && - !virQEMUCapsGet(qemuCaps, QEMU_CAPS_VIRTIO_GPU_BLOB)) { - virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", - _("this QEMU does not support 'blob' for virtio-gpu devices")); - return -1; + if (video->blob != VIR_TRISTATE_SWITCH_ABSENT) { + if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_VIRTIO_GPU_BLOB)) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("this QEMU does not support 'blob' for virtio-gpu devices")); + return -1; + } + if (video->blob == VIR_TRISTATE_SWITCH_ON + && def->mem.source != VIR_DOMAIN_MEMORY_SOURCE_MEMFD) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("'blob' support for virtio-gpu devices requires a memfd memory backend")); + return -1; + } } } @@ -5217,7 +5225,7 @@ qemuValidateDomainDeviceDef(const virDomainDeviceDef *dev, qemuCaps); case VIR_DOMAIN_DEVICE_VIDEO: - return qemuValidateDomainDeviceDefVideo(dev->data.video, qemuCaps); + return qemuValidateDomainDeviceDefVideo(dev->data.video, def, qemuCaps); case VIR_DOMAIN_DEVICE_DISK: return qemuValidateDomainDeviceDefDisk(dev->data.disk, def, qemuCaps); -- 2.41.0