On 01/24/2017 10:40 AM, Michal Privoznik wrote:
So far we allow to set MTU for libvirt networks. However, not all
domain interfaces have to be plugged into a libvirt network and
even if they are, they might want to have a different MTU (e.g.
for testing purposes).
... although setting an MTU larger than a bridge's current MTU will
result in the tap device MTU being lowered back to the bridge's MTU
anyway, and setting an MTU smaller than the bridge's current MTU will
result in the bridge's MTU being clamped to that new lower value.
(Still, I think it's reasonable to expect someone someday will want to
do that for some reason, so might as well allow it...)
Signed-off-by: Michal Privoznik <mprivozn@xxxxxxxxxx>
---
docs/formatdomain.html.in | 19 ++++++++
docs/schemas/domaincommon.rng | 3 ++
docs/schemas/networkcommon.rng | 9 ++++
src/conf/domain_conf.c | 10 +++++
src/conf/domain_conf.h | 1 +
src/qemu/qemu_domain.c | 29 ++++++++++++
src/qemu/qemu_domain.h | 2 +
tests/qemuxml2argvdata/qemuxml2argv-net-mtu.xml | 60 +++++++++++++++++++++++++
8 files changed, 133 insertions(+)
create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-net-mtu.xml
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index 3f7f87524..1bbece0e5 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -5215,6 +5215,25 @@ qemu-kvm -net nic,model=? /dev/null
<span class="since">Since 0.9.5</span>
</p>
+ <h5><a name="mtu">MTU configuration</a></h5>
+<pre>
+...
+<devices>
+ <interface type='network'>
+ <source network='default'/>
+ <target dev='vnet0'/>
+ <b><mtu size='1500'/></b>
+ </interface>
+</devices>
+...</pre>
+
+ <p>
+ This element provides means of setting MTU of the virtual network link.
+ Currently there is just one attribute <code>size</code> which accepts a
+ non-negative integer which specifies the MTU size for the interface.
+ <span class="since">Since 3.1.0</span>
+ </p>
This collection of words has an elevated level of elucidating with the
verbiage and so on. It's all true though. :-)
+
<h5><a name="ipconfig">IP configuration</a></h5>
<pre>
...
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 4d76315b0..cc6e0d0c0 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -2465,6 +2465,9 @@
<empty/>
</element>
</optional>
+ <optional>
+ <ref name="mtu"/>
+ </optional>
<optional>
<element name="target">
<attribute name="dev">
diff --git a/docs/schemas/networkcommon.rng b/docs/schemas/networkcommon.rng
index a334b83e3..26995556d 100644
--- a/docs/schemas/networkcommon.rng
+++ b/docs/schemas/networkcommon.rng
@@ -260,10 +260,19 @@
</optional>
</element>
</define>
+
<define name="macTableManager">
<choice>
<value>kernel</value>
<value>libvirt</value>
</choice>
</define>
+
+ <define name="mtu">
+ <element name="mtu">
+ <attribute name="size">
+ <ref name="unsignedShort"/>
+ </attribute>
+ </element>
+ </define>
Well, if you're going to add this, then I should use it in my patches,
or I should do it and you use it in yours. Our relative timezones (and
the fact that I haven't respun my patches yet) dictate that you should
push first (anyway, I'm realizing I'll need to add an extra patch to
mine for another issue - retrieving the MTU from the network in the
case that it's not specified in the domain's interface element directly,
similar to what we do with vlan tags).
</grammar>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 26bb0fdd0..a2b72cb9c 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -10050,6 +10050,12 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
goto error;
}
+ if (virXPathUInt("string(./mtu/@size)", ctxt, &def->mtu) < -1) {
+ virReportError(VIR_ERR_XML_ERROR, "%s",
+ _("malformed mtu size"));
+ goto error;
+ }
+
cleanup:
ctxt->node = oldnode;
VIR_FREE(macaddr);
@@ -21769,6 +21775,10 @@ virDomainNetDefFormat(virBufferPtr buf,
virBufferAsprintf(buf, "<link state='%s'/>\n",
virDomainNetInterfaceLinkStateTypeToString(def->linkstate));
}
+
+ if (def->mtu)
+ virBufferAsprintf(buf, "<mtu size='%u'/>\n", def->mtu);
+
if (virDomainDeviceInfoFormat(buf, &def->info,
flags | VIR_DOMAIN_DEF_FORMAT_ALLOW_BOOT
| VIR_DOMAIN_DEF_FORMAT_ALLOW_ROM) < 0)
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 78a3db4e1..4d830c51d 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -1009,6 +1009,7 @@ struct _virDomainNetDef {
virNetDevVlan vlan;
int trustGuestRxFilters; /* enum virTristateBool */
int linkstate;
+ unsigned int mtu;
};
/* Used for prefix of ifname of any network name generated dynamically
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 2ed45ab17..26ca89930 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -2868,6 +2868,14 @@ qemuDomainDeviceDefValidate(const virDomainDeviceDef *dev,
_("rx_queue_size has to be a power of two"));
goto cleanup;
}
+
+ if (net->mtu &&
+ !qemuDomainNetSupportsMTU(net->type)) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ _("setting MTU on interface type %s is not supported yet"),
+ virDomainNetTypeToString(net->type));
+ goto cleanup;
+ }
}
ret = 0;
@@ -6529,6 +6537,27 @@ qemuDomainSupportsNetdev(virDomainDefPtr def,
return virQEMUCapsGet(qemuCaps, QEMU_CAPS_NETDEV);
}
+bool
+qemuDomainNetSupportsMTU(virDomainNetType type)
+{
+ switch (type) {
+ case VIR_DOMAIN_NET_TYPE_USER:
+ case VIR_DOMAIN_NET_TYPE_ETHERNET:
+ case VIR_DOMAIN_NET_TYPE_VHOSTUSER:
+ case VIR_DOMAIN_NET_TYPE_SERVER:
+ case VIR_DOMAIN_NET_TYPE_CLIENT:
+ case VIR_DOMAIN_NET_TYPE_MCAST:
+ case VIR_DOMAIN_NET_TYPE_NETWORK:
+ case VIR_DOMAIN_NET_TYPE_BRIDGE:
+ case VIR_DOMAIN_NET_TYPE_INTERNAL:
+ case VIR_DOMAIN_NET_TYPE_DIRECT:
+ case VIR_DOMAIN_NET_TYPE_HOSTDEV:
+ case VIR_DOMAIN_NET_TYPE_UDP:
+ case VIR_DOMAIN_NET_TYPE_LAST:
+ break;
+ }
+ return false;
+}
int
qemuDomainNetVLAN(virDomainNetDefPtr def)
diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index 88b586972..041149167 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -708,6 +708,8 @@ bool qemuDomainSupportsNetdev(virDomainDefPtr def,
virQEMUCapsPtr qemuCaps,
virDomainNetDefPtr net);
+bool qemuDomainNetSupportsMTU(virDomainNetType type);
+
int qemuDomainNetVLAN(virDomainNetDefPtr def);
int qemuDomainSetPrivatePaths(virQEMUDriverPtr driver,
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-net-mtu.xml b/tests/qemuxml2argvdata/qemuxml2argv-net-mtu.xml
new file mode 100644
index 000000000..606322463
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-net-mtu.xml
You added this test case, but didn't reference it in qemuxml2xmltest.c
(or add the corresponding file in qemuxml2xmloutdata).
Ah, I see you did add it in patch 4/4, but I think the xml2xml test
should be added in the same patch that the conf changes are made.
@@ -0,0 +1,60 @@
+<domain type='qemu'>
+ <name>test</name>
+ <uuid>15d091de-0181-456b-9554-e4382dc1f1ab</uuid>
+ <memory unit='KiB'>1048576</memory>
+ <currentMemory unit='KiB'>1048576</currentMemory>
+ <vcpu placement='static'>1</vcpu>
+ <os>
+ <type arch='x86_64' machine='pc-0.13'>hvm</type>
+ <boot dev='cdrom'/>
+ <boot dev='hd'/>
+ <bootmenu enable='yes'/>
+ </os>
+ <clock offset='utc'/>
+ <on_poweroff>destroy</on_poweroff>
+ <on_reboot>restart</on_reboot>
+ <on_crash>restart</on_crash>
+ <devices>
+ <emulator>/usr/bin/qemu</emulator>
+ <disk type='file' device='disk'>
+ <driver name='qemu' type='qcow2' event_idx='on'/>
+ <source file='/var/lib/libvirt/images/f14.img'/>
+ <target dev='vda' bus='virtio'/>
+ <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
+ </disk>
+ <disk type='file' device='cdrom'>
+ <driver name='qemu' type='raw'/>
+ <source file='/var/lib/libvirt/Fedora-14-x86_64-Live-KDE.iso'/>
+ <target dev='hdc' bus='ide'/>
+ <readonly/>
+ <address type='drive' controller='0' bus='1' target='0' unit='0'/>
+ </disk>
+ <controller type='usb' index='0'/>
+ <controller type='virtio-serial' index='0'>
+ <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
+ </controller>
+ <controller type='ide' index='0'/>
+ <controller type='pci' index='0' model='pci-root'/>
+ <interface type='network'>
+ <source network='default'/>
+ <mac address='52:54:00:e5:48:58'/>
+ <model type='virtio'/>
+ <mtu size='1500'/>
+ </interface>
+ <interface type='network'>
+ <source network='default'/>
+ <mac address='52:54:00:e5:48:59'/>
+ <model type='virtio'/>
+ <mtu size='9000'/>
+ </interface>
+ <serial type='pty'>
+ <target port='0'/>
+ </serial>
+ <console type='pty'>
+ <target type='serial' port='0'/>
+ </console>
+ <input type='mouse' bus='ps2'/>
+ <input type='keyboard' bus='ps2'/>
+ <memballoon model='virtio'/>
+ </devices>
+</domain>
Long test cases with lots of extra stuff already tested elsewhere make
jtomko cry :-P.
ACK, if you move the xml2xml test case to this patch.
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