Re: [PATCH] Add page_per_vq flag to the 'driver' element of virtio devices

https://bugzilla.redhat.com/show_bug.cgi?id=1925363 Add support for setting the page-per-vq flag, which is important for vdpa with vhost-user performance. Signed-off-by: Gavi Teitz <gavi(a)nvidia.com&gt; --- docs/formatdomain.rst | 11 +++++- docs/schemas/domaincommon.rng | 5 +++ src/conf/domain_conf.c | 15 ++++++++ src/conf/domain_conf.h | 1 + src/qemu/qemu_capabilities.c | 2 + src/qemu/qemu_capabilities.h | 1 + src/qemu/qemu_command.c | 5 +++ src/qemu/qemu_hotplug.c | 1 + tests/qemuxml2argvdata/net-virtio-page-per-vq.args | 31 ++++++++++++++++ tests/qemuxml2argvdata/net-virtio-page-per-vq.xml | 29 +++++++++++++++ tests/qemuxml2argvtest.c | 2 + .../qemuxml2xmloutdata/net-virtio-page-per-vq.xml | 43 ++++++++++++++++++++++ tests/qemuxml2xmltest.c | 2 + 13 files changed, 147 insertions(+), 1 deletion(-) create mode 100644 tests/qemuxml2argvdata/net-virtio-page-per-vq.args create mode 100644 tests/qemuxml2argvdata/net-virtio-page-per-vq.xml create mode 100644 tests/qemuxml2xmloutdata/net-virtio-page-per-vq.xml diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst index 282176c..f5a9c70 100644 --- a/docs/formatdomain.rst +++ b/docs/formatdomain.rst @@ -5120,7 +5120,7 @@ Setting NIC driver-specific options <source network='default'/> <target dev='vnet1'/> <model type='virtio'/> - <driver name='vhost' txmode='iothread' ioeventfd='on' event_idx='off' queues='5' rx_queue_size='256' tx_queue_size='256'> + <driver name='vhost' txmode='iothread' ioeventfd='on' event_idx='off' queues='5' rx_queue_size='256' tx_queue_size='256' page_per_vq='on'> <host csum='off' gso='off' tso4='off' tso6='off' ecn='off' ufo='off' mrg_rxbuf='off'/> <guest csum='off' tso4='off' tso6='off' ecn='off' ufo='off'/> </driver> @@ -5215,6 +5215,15 @@ following attributes are available for the ``"virtio"`` NIC driver: only for ``vhostuser`` type. :since:`Since 3.7.0 (QEMU and KVM only)` **In general you should leave this option alone, unless you are very certain you know what you are doing.** +``page_per_vq`` + This optional attribute controls the layout of the notification capabilities + exposed to the guest. When enabled, each virtio queue will have a dedicated + page on the device BAR exposed to the guest. It is recommended to be used when + vDPA is enabled on the hypervisor, as it enables mapping the notification area + to the physical device, which is only supported in page granularity. The + default is determined by QEMU; as off. :since:`Since 2.8.0 (QEMU only)`

+ **In general you should leave this option alone, unless you are very certain + you know what you are doing.** virtio options For virtio interfaces, `Virtio-specific options <#elementsVirtio>`__ can also be set. ( :since:`Since 3.5.0` ) diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng index a2e5c50..e61ad67 100644 --- a/docs/schemas/domaincommon.rng +++ b/docs/schemas/domaincommon.rng @@ -3463,6 +3463,11 @@ </attribute> </optional> <optional> + <attribute name="page_per_vq"> + <ref name="virOnOff"/> + </attribute> + </optional> + <optional> <attribute name="txmode"> <choice> <value>iothread</value>

@@ -1405,6 +1406,7 @@ static struct virQEMUCapsDevicePropsFlags virQEMUCapsDevicePropsVirtioNet[] = { { "event_idx", QEMU_CAPS_VIRTIO_NET_EVENT_IDX, NULL }, { "rx_queue_size", QEMU_CAPS_VIRTIO_NET_RX_QUEUE_SIZE, NULL }, { "tx_queue_size", QEMU_CAPS_VIRTIO_NET_TX_QUEUE_SIZE, NULL }, + { "page_per_vq", QEMU_CAPS_VIRTIO_NET_PAGE_PER_VQ, NULL }, { "host_mtu", QEMU_CAPS_VIRTIO_NET_HOST_MTU, NULL }, { "disable-legacy", QEMU_CAPS_VIRTIO_PCI_DISABLE_LEGACY, NULL }, { "iommu_platform", QEMU_CAPS_VIRTIO_PCI_IOMMU_PLATFORM, NULL }, diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h index f54aad5..75feed4 100644 --- a/src/qemu/qemu_capabilities.h +++ b/src/qemu/qemu_capabilities.h @@ -609,6 +609,7 @@ typedef enum { /* virQEMUCapsFlags grouping marker for syntax-check */ /* 400 */ QEMU_CAPS_COMPAT_DEPRECATED, /* -compat deprecated-(input|output) is supported */ QEMU_CAPS_ACPI_INDEX, /* PCI device 'acpi-index' property */ + QEMU_CAPS_VIRTIO_NET_PAGE_PER_VQ, /* virtio-net-*.page_per_vq */ QEMU_CAPS_LAST /* this must always be the last item */ } virQEMUCapsFlags;

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index d7f1c71..7b5834f 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -3630,6 +3630,11 @@ qemuBuildNicDevStr(virDomainDef *def, if (net->driver.virtio.tx_queue_size) virBufferAsprintf(&buf, ",tx_queue_size=%u", net->driver.virtio.tx_queue_size); + if (net->driver.virtio.page_per_vq) { + virBufferAsprintf(&buf, ",page-per-vq=%s", + virTristateSwitchTypeToString(net->driver.virtio.page_per_vq)); + } + if (net->mtu) virBufferAsprintf(&buf, ",host_mtu=%u", net->mtu);

diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c index f0efe98..f6b8f34 100644 --- a/tests/qemuxml2argvtest.c +++ b/tests/qemuxml2argvtest.c @@ -1654,6 +1654,8 @@ mymain(void) QEMU_CAPS_VIRTIO_NET_TX_QUEUE_SIZE); DO_TEST_PARSE_ERROR("net-virtio-rxqueuesize-invalid-size", QEMU_CAPS_VIRTIO_NET_RX_QUEUE_SIZE); + DO_TEST("net-virtio-page-per-vq", + QEMU_CAPS_VIRTIO_NET_PAGE_PER_VQ);

DO_TEST("net-virtio-teaming", QEMU_CAPS_VIRTIO_NET_FAILOVER, QEMU_CAPS_DEVICE_VFIO_PCI);