Re: [libvirt PATCH v5 4/6] conf: add support for 'blob' in virtio video device

Add the ability to enable blob resources for the virtio video device. This will accelerate the display path due to less or no copying of pixel data. Blob resource support can be enabled with e.g.: <video> <model type='virtio' blob='on'/> </video> Some additional background information about blob resources: https://lists.freedesktop.org/archives/dri-devel/2020-August/275972.html https://www.kraxel.org/blog/2021/05/virtio-gpu-qemu-graphics-update/ Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2032406 Signed-off-by: Jonathon Jongsma <jjongsma(a)redhat.com&gt; --- docs/formatdomain.rst | 7 +++++++ src/conf/domain_conf.c | 6 ++++++ src/conf/domain_conf.h | 1 + src/conf/domain_validate.c | 13 ++++++++++--- src/conf/schemas/domaincommon.rng | 5 +++++ 5 files changed, 29 insertions(+), 3 deletions(-) diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst index e28b805009..b057fc4703 100644 --- a/docs/formatdomain.rst +++ b/docs/formatdomain.rst @@ -6346,6 +6346,13 @@ A video device. :since:`since 1.3.3` ) extends secondary bar and makes it addressable as 64bit memory. + :since:`Since 8.10.0` (QEMU driver only), devices with type "virtio" have an + optional ``blob`` attribute that can be set to "on" or "off". Setting + ``blob`` to "on" will enable the use of blob resources in the device. This + can accelerate the display path by reducing or eliminating copying of pixel + data between the guest and host. Note that blob resource support requires + QEMU version 6.1 or newer. + :since:`Since 5.9.0` , the ``model`` element may also have an optional ``resolution`` sub-element. The ``resolution`` element has attributes ``x`` and ``y`` to set the minimum resolution for the video device. This diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 7484059e47..adbb41d19e 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -12583,6 +12583,9 @@ virDomainVideoModelDefParseXML(virDomainVideoDef *def, else if (rc == 0) def->heads = 1; + if (virXMLPropTristateSwitch(node, "blob", VIR_XML_PROP_NONE, &def->blob) < 0) + return -1; + return 0; } @@ -24623,6 +24626,9 @@ virDomainVideoDefFormat(virBuffer *buf, virBufferAsprintf(buf, " heads='%u'", def->heads); if (def->primary) virBufferAddLit(buf, " primary='yes'"); + if (def->blob != VIR_TRISTATE_SWITCH_ABSENT) + virBufferAsprintf(buf, " blob='%s'", + virTristateSwitchTypeToString(def->blob));

if (def->accel || def->res) { virBufferAddLit(buf, ">\n"); virBufferAdjustIndent(buf, 2);