[libvirt] [PATCHv2 4/6] API: Introduce VIR_DOMAIN_VCPU_AGENT, for agent based CPU hot(un)plug
Peter Krempa
pkrempa at redhat.com
Tue Apr 16 14:00:10 UTC 2013
This flag will allow to use qemu guest agent commands to disable
(offline) and enable (online) processors in a live guest that has the
guest agent running.
---
Notes:
Version 2:
- improve api docs
- reject _MAXIMUM and _AGENT to the setter func
- break long line
include/libvirt/libvirt.h.in | 1 +
src/libvirt.c | 24 ++++++++++++++++++++++--
tools/virsh-domain.c | 25 +++++++++++++++++++++++--
tools/virsh.pod | 13 ++++++++++---
4 files changed, 56 insertions(+), 7 deletions(-)
diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
index 518f0fe..f12173d 100644
--- a/include/libvirt/libvirt.h.in
+++ b/include/libvirt/libvirt.h.in
@@ -2120,6 +2120,7 @@ typedef enum {
/* Additionally, these flags may be bitwise-OR'd in. */
VIR_DOMAIN_VCPU_MAXIMUM = (1 << 2), /* Max rather than current count */
+ VIR_DOMAIN_VCPU_AGENT = (1 << 3), /* Use guest-agent based cpu hotplug */
} virDomainVcpuFlags;
int virDomainSetVcpus (virDomainPtr domain,
diff --git a/src/libvirt.c b/src/libvirt.c
index 870519e..ecfc1a6 100644
--- a/src/libvirt.c
+++ b/src/libvirt.c
@@ -8898,6 +8898,12 @@ error:
* equal to virConnectGetMaxVcpus(). Otherwise, this call affects the
* current virtual CPU limit, which must be less than or equal to the
* maximum limit.
+ *
+ * If @flags includes VIR_DOMAIN_VCPU_AGENT, then a guest agent is used to
+ * modify the number of processors used by a domain. This flag can only be used
+ * with live guests and is incompatible with VIR_DOMAIN_VCPU_MAXIMUM as the
+ * maximum limit can't be changed using the guest agent.
+ *
* Not all hypervisors can support all flag combinations.
*
* Returns 0 in case of success, -1 in case of failure.
@@ -8923,6 +8929,15 @@ virDomainSetVcpusFlags(virDomainPtr domain, unsigned int nvcpus,
goto error;
}
+ if (flags & VIR_DOMAIN_VCPU_AGENT &&
+ flags & VIR_DOMAIN_VCPU_MAXIMUM) {
+ virReportInvalidArg(flags,
+ _("flags 'VIR_DOMAIN_VCPU_MAXIMUM' and "
+ "'VIR_DOMAIN_VCPU_AGENT' in '%s' are mutually "
+ "exclusive"), __FUNCTION__);
+ goto error;
+ }
+
virCheckNonZeroArgGoto(nvcpus, error);
if ((unsigned short) nvcpus != nvcpus) {
@@ -8966,7 +8981,11 @@ error:
*
* If @flags includes VIR_DOMAIN_VCPU_MAXIMUM, then the maximum
* virtual CPU limit is queried. Otherwise, this call queries the
- * current virtual CPU limit.
+ * current virtual CPU count.
+ *
+ * If @flags includes VIR_DOMAIN_VCPU_AGENT, then a guest agent is used to
+ * modify the number of processors used by a domain. This flag is only usable on
+ * live domains.
*
* Returns the number of vCPUs in case of success, -1 in case of failure.
*/
@@ -8990,7 +9009,8 @@ virDomainGetVcpusFlags(virDomainPtr domain, unsigned int flags)
if ((flags & VIR_DOMAIN_AFFECT_LIVE) &&
(flags & VIR_DOMAIN_AFFECT_CONFIG)) {
virReportInvalidArg(flags,
- _("flags 'affect live' and 'affect config' in %s are mutually exclusive"),
+ _("flags 'affect live' and 'affect config' in %s "
+ "are mutually exclusive"),
__FUNCTION__);
goto error;
}
diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
index 5726744..627b717 100644
--- a/tools/virsh-domain.c
+++ b/tools/virsh-domain.c
@@ -5084,6 +5084,10 @@ static const vshCmdOptDef opts_vcpucount[] = {
.type = VSH_OT_BOOL,
.help = N_("get value according to current domain state")
},
+ {.name = "agent",
+ .type = VSH_OT_BOOL,
+ .help = N_("use guest agent based hotplug")
+ },
{.name = NULL}
};
@@ -5126,6 +5130,11 @@ vshCPUCountCollect(vshControl *ctl,
last_error->code == VIR_ERR_INVALID_ARG))
goto cleanup;
+ if (flags & VIR_DOMAIN_VCPU_AGENT) {
+ vshError(ctl, "%s", _("Failed to retrieve vCPU count via guest agent"));
+ goto cleanup;
+ }
+
if (!(flags & (VIR_DOMAIN_AFFECT_LIVE | VIR_DOMAIN_AFFECT_CONFIG)) &&
virDomainIsActive(dom) == 1)
flags |= VIR_DOMAIN_AFFECT_LIVE;
@@ -5181,7 +5190,8 @@ cmdVcpucount(vshControl *ctl, const vshCmd *cmd)
bool config = vshCommandOptBool(cmd, "config");
bool live = vshCommandOptBool(cmd, "live");
bool current = vshCommandOptBool(cmd, "current");
- bool all = maximum + active + current + config + live == 0;
+ bool agent = vshCommandOptBool(cmd, "agent");
+ bool all = maximum + active + current + config + live + agent == 0;
unsigned int flags = VIR_DOMAIN_AFFECT_CURRENT;
/* Backwards compatibility: prior to 0.9.4,
@@ -5196,6 +5206,7 @@ cmdVcpucount(vshControl *ctl, const vshCmd *cmd)
VSH_EXCLUSIVE_OPTIONS_VAR(current, live);
VSH_EXCLUSIVE_OPTIONS_VAR(current, config);
VSH_EXCLUSIVE_OPTIONS_VAR(active, maximum);
+ VSH_EXCLUSIVE_OPTIONS_VAR(agent, config);
if (live)
flags |= VIR_DOMAIN_AFFECT_LIVE;
@@ -5203,6 +5214,8 @@ cmdVcpucount(vshControl *ctl, const vshCmd *cmd)
flags |= VIR_DOMAIN_AFFECT_CONFIG;
if (maximum)
flags |= VIR_DOMAIN_VCPU_MAXIMUM;
+ if (agent)
+ flags |= VIR_DOMAIN_VCPU_AGENT;
if (!(dom = vshCommandOptDomain(ctl, cmd, NULL)))
return false;
@@ -5795,6 +5808,10 @@ static const vshCmdOptDef opts_setvcpus[] = {
.type = VSH_OT_BOOL,
.help = N_("affect current domain")
},
+ {.name = "agent",
+ .type = VSH_OT_BOOL,
+ .help = N_("use guest agent based hotplug")
+ },
{.name = NULL}
};
@@ -5808,17 +5825,21 @@ cmdSetvcpus(vshControl *ctl, const vshCmd *cmd)
bool config = vshCommandOptBool(cmd, "config");
bool live = vshCommandOptBool(cmd, "live");
bool current = vshCommandOptBool(cmd, "current");
+ bool agent = vshCommandOptBool(cmd, "agent");
unsigned int flags = VIR_DOMAIN_AFFECT_CURRENT;
VSH_EXCLUSIVE_OPTIONS_VAR(current, live);
VSH_EXCLUSIVE_OPTIONS_VAR(current, config);
+ VSH_EXCLUSIVE_OPTIONS_VAR(agent, config);
if (config)
flags |= VIR_DOMAIN_AFFECT_CONFIG;
if (live)
flags |= VIR_DOMAIN_AFFECT_LIVE;
+ if (agent)
+ flags |= VIR_DOMAIN_VCPU_AGENT;
/* none of the options were specified */
- if (!current && !live && !config && !maximum)
+ if (!current && flags == 0)
flags = -1;
if (!(dom = vshCommandOptDomain(ctl, cmd, NULL)))
diff --git a/tools/virsh.pod b/tools/virsh.pod
index 11984bc..49438aa 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -1585,7 +1585,7 @@ exclusive. If no flag is specified, behavior is different depending
on hypervisor.
=item B<setvcpus> I<domain> I<count> [I<--maximum>] [[I<--config>]
-[I<--live>] | [I<--current>]]
+[I<--live>] | [I<--current>]] [I<--agent>]
Change the number of virtual CPUs active in a guest domain. By default,
this command works on active guest domains. To change the settings for an
@@ -1611,6 +1611,10 @@ is up to the hypervisor whether the I<--config> flag is also assumed, and
therefore whether the XML configuration is adjusted to make the change
persistent.
+If I<--agent> is specified, then guest agent commands are used to retrieve the
+count of available vCPUs from the perspective of the guest. This flag is usable
+only for live domains.
+
The I<--maximum> flag controls the maximum number of virtual cpus that can
be hot-plugged the next time the domain is booted. As such, it must only be
used with the I<--config> flag, and not with the I<--live> flag.
@@ -1730,7 +1734,7 @@ NOTE: For an inactive domain, the domain name or UUID must be used as the
I<domain>.
=item B<vcpucount> I<domain> [{I<--maximum> | I<--active>}
-{I<--config> | I<--live> | I<--current>}]
+{I<--config> | I<--live> | I<--current>}] [I<--agent>]
Print information about the virtual cpu counts of the given
I<domain>. If no flags are specified, all possible counts are
@@ -1747,7 +1751,10 @@ time the domain will be booted, I<--live> requires a running domain and
lists current values, and I<--current> queries according to the current
state of the domain (corresponding to I<--live> if running, or
I<--config> if inactive); these three flags are mutually exclusive.
-Thus, this command always takes exactly zero or two flags.
+
+If I<--agent> is specified, then guest agent commands are used to retrieve the
+count of available vCPUs from the perspective of the guest. This flag is usable
+only for live domains.
=item B<vcpuinfo> I<domain>
--
1.8.1.5
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