6:54 a.m.
https://bugzilla.redhat.com/show_bug.cgi?id=1366989
Qemu grew yet another virtio-net tunable [1]. It basically allows
users to set the size of RX virtio ring. But because virtio-net
uses two separate ring buffers to pass data from/to guest they
named it explicitly rx_queue_size. We should expose it in our XML
too.
1: http://lists.nongnu.org/archive/html/qemu-devel/2016-08/msg02029.html
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
docs/formatdomain.html.in | 7 +++++-
docs/schemas/domaincommon.rng | 5 ++++
src/conf/domain_conf.c | 16 ++++++++++++
src/conf/domain_conf.h | 1 +
src/qemu/qemu_domain.c | 7 ++++++
.../qemuxml2argv-net-virtio-rxqueuesize.xml | 29 ++++++++++++++++++++++
6 files changed, 64 insertions(+), 1 deletion(-)
create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-net-virtio-rxqueuesize.xml
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index bfbb0f2..6642dc8 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -4604,7 +4604,7 @@ qemu-kvm -net nic,model=? /dev/null
<source network='default'/>
<target dev='vnet1'/>
<model type='virtio'/>
- <b><driver name='vhost' txmode='iothread'
ioeventfd='on' event_idx='off' queues='5'>
+ <b><driver name='vhost' txmode='iothread'
ioeventfd='on' event_idx='off' queues='5'
rxqueuesize='128'>
<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>
@@ -4720,6 +4720,11 @@ qemu-kvm -net nic,model=? /dev/null
<span class="since">virtio-net since 1.0.6 (QEMU and KVM
only)</span>
<span class="since">vhost-user since 1.2.17 (QEMU and KVM
only)</span>
</dd>
+ <dt><code>rxqueuesize</code></dt>
+ <dd>
+ The optional <code>rxqueuesize</code> attribute controls
+ the size of virtio ring for each queue as described above.
+ </dd>
</dl>
<p>
Offloading options for the host and guest can be configured using
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 052f28c..4b89a86 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -2529,6 +2529,11 @@
</attribute>
</optional>
<optional>
+ <attribute name='rxqueuesize'>
+ <ref name='positiveInteger'/>
+ </attribute>
+ </optional>
+ <optional>
<attribute name="txmode">
<choice>
<value>iothread</value>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 14d4f7d..08cde19 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -8911,6 +8911,7 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
char *ioeventfd = NULL;
char *event_idx = NULL;
char *queues = NULL;
+ char *rxqueuesize = NULL;
char *str = NULL;
char *filter = NULL;
char *internal = NULL;
@@ -9083,6 +9084,7 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
ioeventfd = virXMLPropString(cur, "ioeventfd");
event_idx = virXMLPropString(cur, "event_idx");
queues = virXMLPropString(cur, "queues");
+ rxqueuesize = virXMLPropString(cur, "rxqueuesize");
} else if (xmlStrEqual(cur->name, BAD_CAST "filterref")) {
if (filter) {
virReportError(VIR_ERR_XML_ERROR, "%s",
@@ -9466,6 +9468,17 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
if (q > 1)
def->driver.virtio.queues = q;
}
+ if (rxqueuesize) {
+ unsigned int q;
+ if (virStrToLong_uip(rxqueuesize, NULL, 10, &q) < 0) {
+ virReportError(VIR_ERR_XML_DETAIL,
+ _("'rxqueuesize' attribute must be positive
number: %s"),
+ rxqueuesize);
+ goto error;
+ }
+ if (q > 1)
+ def->driver.virtio.rxqueuesize = q;
+ }
if ((str = virXPathString("string(./driver/host/@csum)", ctxt))) {
if ((val = virTristateSwitchTypeFromString(str)) <= 0) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
@@ -9646,6 +9659,7 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
VIR_FREE(ioeventfd);
VIR_FREE(event_idx);
VIR_FREE(queues);
+ VIR_FREE(rxqueuesize);
VIR_FREE(str);
VIR_FREE(filter);
VIR_FREE(type);
@@ -20768,6 +20782,8 @@ virDomainVirtioNetDriverFormat(char **outstr,
}
if (def->driver.virtio.queues)
virBufferAsprintf(&buf, "queues='%u' ",
def->driver.virtio.queues);
+ if (def->driver.virtio.rxqueuesize)
+ virBufferAsprintf(&buf, "rxqueuesize='%u' ",
def->driver.virtio.rxqueuesize);
virBufferTrim(&buf, " ", -1);
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 8b26724..9197d70 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -906,6 +906,7 @@ struct _virDomainNetDef {
virTristateSwitch ioeventfd;
virTristateSwitch event_idx;
unsigned int queues; /* Multiqueue virtio-net */
+ unsigned int rxqueuesize; /* rx_queue_size */
struct {
virTristateSwitch csum;
virTristateSwitch gso;
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 6c0f261..ee24086 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -2372,6 +2372,13 @@ qemuDomainDeviceDefValidate(const virDomainDeviceDef *dev,
"not supported by QEMU"));
goto cleanup;
}
+
+ if (STREQ_NULLABLE(net->model, "virtio") &&
+ net->driver.virtio.rxqueuesize & (net->driver.virtio.rxqueuesize
-1)) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+ _("rxqueuesize has to be a power of two"));
+ goto cleanup;
+ }
}
ret = 0;
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-rxqueuesize.xml
b/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-rxqueuesize.xml
new file mode 100644
index 0000000..e23d3e3
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-net-virtio-rxqueuesize.xml
@@ -0,0 +1,29 @@
+<domain type='qemu'>
+ <name>QEMUGuest1</name>
+ <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+ <memory unit='KiB'>219100</memory>
+ <currentMemory unit='KiB'>219100</currentMemory>
+ <vcpu placement='static'>1</vcpu>
+ <os>
+ <type arch='i686' machine='pc'>hvm</type>
+ <boot dev='hd'/>
+ </os>
+ <clock offset='utc'/>
+ <on_poweroff>destroy</on_poweroff>
+ <on_reboot>restart</on_reboot>
+ <on_crash>destroy</on_crash>
+ <devices>
+ <emulator>/usr/bin/qemu</emulator>
+ <disk type='block' device='disk'>
+ <source dev='/dev/HostVG/QEMUGuest1'/>
+ <target dev='hda' bus='ide'/>
+ </disk>
+ <controller type='usb' index='0'/>
+ <interface type='user'>
+ <mac address='00:11:22:33:44:55'/>
+ <model type='virtio'/>
+ <driver rxqueuesize='128'/>
+ </interface>
+ <memballoon model='virtio'/>
+ </devices>
+</domain>
--
2.8.4