6:45 p.m.
On 11/23/2015 11:57 AM, Joao Martins wrote:
Introduce support for domainInterfaceStats API call for querying
network interface statistics. Consequently it also enables the
use of `virsh domifstat <dom> <interface name>` command plus
seeing the interfaces names instead of "-" when doing
`virsh domiflist <dom>`.
After successful guest creation we fill the network
interfaces names based on domain, device id and append suffix
if it's emulated in the following form: vif<domid>.<devid>[-emu].
One interesting Xen behavior that has existing for many, many years is that a PV
nic is implicitly created for each emulated nic specified in the config. The
guest OS picks which one to use. These days most will use the PV nic, and if
they are nice, "unplug" the emulated one via the unplug protocol. E.g. an HVM
guest with
<interface type='bridge'>
<source bridge='br0'/>
<mac address='00:16:3e:7a:35:ce'/>
<script path='/etc/xen/scripts/vif-bridge'/>
</interface>
results in two vif devices on the host
# ip a | grep vif
607: vif519.0-emu: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
master br0 state UNKNOWN group default qlen 500
608: vif519.0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
master br0 state UNKNOWN group default qlen 512
both are connected to the bridge
# brctl show br0
bridge name bridge id STP enabled interfaces
br0 8000.001e676598f5 no eth0
vif519.0
vif519.0-emu
In this case, the (not nice) guest OS is using the PV nic but did not unplug the
emulated one. So we have two interfaces, but the virDomainDef only contains one
# virsh domiflist 519
Interface Type Source Model MAC
-------------------------------------------------------
vif519.0-emu bridge br0 - 00:16:3e:7a:35:ce
Not a fault of this patch, but we'll need to figure out how to handle the
implicitly created PV nic. The interesting case is identifying emulated nics
that have been unplugged by a nice guest, and hence no longer exist in the host
(e.g. vif519.0-emu in the above example).
We extract the network interfaces info from libxl in
libxlDomainStartCallback() and make ifname . On domain
cleanup we also clear ifname, in case it was set by libvirt (i.e.
being prefixed with "vif"). We also skip these two steps in case the name
of the interface was manually inserted by the adminstrator.
For getting the interface statistics we resort to virNetInterfaceStats
and let libvirt handle the platform specific nits. Note that the latter
is not yet supported in FreeBSD.
Signed-off-by: Joao Martins <joao.m.martins(a)oracle.com>
---
Changes since v3:
- Use libxl_device_nic_list() for getting each network interface
devid in DomainStartCallback.
- Improve error reporting by appropriately setting the right error
when no interface is known.
- Do not unlock vm if libxlDomainObjEndJob() returns false
- Set vm->def->net[i]->ifname on DomainStartCallback instead of
DomainStart.
- Change commit message reflecting the changes on the previous
item and mention correct interface names when doing domiflist.
Changes since v2:
- Clear ifname if it's autogenerated, since otherwise will persist
on successive domain starts. Change commit message reflecting this
change.
Changes since v1:
- Fill <virDomainNetDef>.ifname after domain start with generated
name from libxl based on domain id and devid returned by libxl.
After that path validation don interfaceStats is enterily based
on ifname pretty much like the other drivers.
- Modify commit message reflecting the changes mentioned in
the previous item.
- Bump version to 1.2.22
---
src/libxl/libxl_domain.c | 29 +++++++++++++++++++++++++++
src/libxl/libxl_driver.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 81 insertions(+)
diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c
index a7267b0..141f241 100644
--- a/src/libxl/libxl_domain.c
+++ b/src/libxl/libxl_domain.c
@@ -728,6 +728,17 @@ libxlDomainCleanup(libxlDriverPrivatePtr driver,
}
}
+ if ((vm->def->nnets)) {
+ ssize_t i;
size_t
+
+ for (i = 0; i < vm->def->nnets; i++) {
+ virDomainNetDefPtr net = vm->def->nets[i];
+
+ if (STRPREFIX(net->ifname, "vif"))
+ VIR_FREE(net->ifname);
+ }
+ }
+
if (virAsprintf(&file, "%s/%s.xml", cfg->stateDir,
vm->def->name) > 0) {
if (unlink(file) < 0 && errno != ENOENT && errno != ENOTDIR)
VIR_DEBUG("Failed to remove domain XML for %s",
vm->def->name);
@@ -857,6 +868,8 @@ static void
libxlDomainStartCallback(libxl_ctx *ctx, libxl_event *ev, void *for_callback)
{
virDomainObjPtr vm = for_callback;
+ libxl_device_nic *nics;
+ int nnics;
size_t i;
virObjectLock(vm);
@@ -883,6 +896,22 @@ libxlDomainStartCallback(libxl_ctx *ctx, libxl_event *ev, void
*for_callback)
VIR_FREE(console);
}
}
+
+ if ((nics = libxl_device_nic_list(ctx, ev->domid, &nnics)) != NULL) {
+ for (i = 0; i < vm->def->nnets && i < nnics; i++) {
+ virDomainNetDefPtr net = vm->def->nets[i];
+ libxl_device_nic *x_nic = &nics[i];
+ const char *suffix =
+ x_nic->nictype != LIBXL_NIC_TYPE_VIF ? "-emu" :
"";
+
+ if (net->ifname)
+ continue;
+
+ if (virAsprintf(&net->ifname, "vif%d.%d%s",
+ ev->domid, x_nic->devid, suffix) < 0)
+ continue;
+ }
+ }
As mentioned in my reply to 1/2, I think we should simply create the names after
a successful libxl_domain_create_{new,restore}. Aside from the implicit PV nic
issue, the patch works for me with the below diff squashed in. What do you think
of this change? Does it work for you?
Regards,
Jim
diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c
index b45cd27..086406b 100644
--- a/src/libxl/libxl_domain.c
+++ b/src/libxl/libxl_domain.c
@@ -729,7 +729,7 @@ libxlDomainCleanup(libxlDriverPrivatePtr driver,
}
if ((vm->def->nnets)) {
- ssize_t i;
+ size_t i;
for (i = 0; i < vm->def->nnets; i++) {
virDomainNetDefPtr net = vm->def->nets[i];
@@ -868,8 +868,6 @@ static void
libxlConsoleCallback(libxl_ctx *ctx, libxl_event *ev, void *for_callback)
{
virDomainObjPtr vm = for_callback;
- libxl_device_nic *nics;
- int nnics;
size_t i;
virObjectLock(vm);
@@ -897,25 +895,35 @@ libxlConsoleCallback(libxl_ctx *ctx, libxl_event *ev, void
*for_callback)
}
}
- if ((nics = libxl_device_nic_list(ctx, ev->domid, &nnics)) != NULL) {
- for (i = 0; i < vm->def->nnets && i < nnics; i++) {
- virDomainNetDefPtr net = vm->def->nets[i];
- libxl_device_nic *x_nic = &nics[i];
- const char *suffix =
- x_nic->nictype != LIBXL_NIC_TYPE_VIF ? "-emu" :
"";
-
- if (net->ifname)
- continue;
-
- if (virAsprintf(&net->ifname, "vif%d.%d%s",
- ev->domid, x_nic->devid, suffix) < 0)
- continue;
- }
- }
virObjectUnlock(vm);
libxl_event_free(ctx, ev);
}
+/*
+ * Create interface names for the network devices in parameter def.
+ * Names are created with the pattern
'vif<domid>.<devid><suffix>'.
+ * devid is extracted from the network devices in the d_config
+ * parameter. User-provided interface names are skipped.
+ */
+static void
+libxlDomainCreateIfaceNames(virDomainDefPtr def, libxl_domain_config *d_config)
+{
+ size_t i;
+
+ for (i = 0; i < def->nnets && i < d_config->num_nics; i++) {
+ virDomainNetDefPtr net = def->nets[i];
+ libxl_device_nic *x_nic = &d_config->nics[i];
+ const char *suffix =
+ x_nic->nictype != LIBXL_NIC_TYPE_VIF ? "-emu" : "";
+
+ if (net->ifname)
+ continue;
+
+ ignore_value(virAsprintf(&net->ifname, "vif%d.%d%s",
+ def->id, x_nic->devid, suffix));
+ }
+}
+
/*
* Start a domain through libxenlight.
@@ -1056,6 +1064,7 @@ libxlDomainStart(libxlDriverPrivatePtr driver,
virDomainObjPtr vm,
if (libxl_evenable_domain_death(cfg->ctx, vm->def->id, 0,
&priv->deathW))
goto cleanup_dom;
+ libxlDomainCreateIfaceNames(vm->def, &d_config);
if ((dom_xml = virDomainDefFormat(vm->def, 0)) == NULL)
goto cleanup_dom;
j