On 04/15/2013 09:11 AM, Peter Krempa wrote: Subject line is long, and doesn't match...
This flag will allow to use qemu guest agent commands to disable processors in a live guest. --- include/libvirt/libvirt.h.in | 1 + src/libvirt.c | 7 +++++++ tools/virsh-domain.c | 25 +++++++++++++++++++++++-- tools/virsh.pod | 13 ++++++++++--- 4 files changed, 41 insertions(+), 5 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 */
...actual flag name. May I suggest: API: add VIR_DOMAIN_VCPU_AGENT for agent-based vcpu hotplug
} virDomainVcpuFlags;
int virDomainSetVcpus (virDomainPtr domain, diff --git a/src/libvirt.c b/src/libvirt.c index c8728b7..0b780cf 100644 --- a/src/libvirt.c +++ b/src/libvirt.c @@ -8887,6 +8887,10 @@ 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.
I'm assuming that VCPU_AGENT and VCPU_MAXIMUM are mutually exclusive (the guest cannot increase or decrease the maximum number of vcpus that the hypervisor uses as its limit); also the flag is useless if not specified on a running domain. Probably worth mentioning this in the docs.
+ * * Not all hypervisors can support all flag combinations. * * Returns 0 in case of success, -1 in case of failure. @@ -8957,6 +8961,9 @@ error: * virtual CPU limit is queried. Otherwise, this call queries the * current virtual CPU 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 is under virDomainGetVcpusFlags(), which reads rather than queries the number of processors. But here, VCPU_AGENT|MAXIMUM makes sense - a guest might see a (smaller) maximum of possible vcpus that could still be hotplugged, in relation to the hypervisor limit.
+ * * Returns the number of vCPUs in case of success, -1 in case of failure. */
You should probably encode any mutual exclusion directly into libvirt.c, so that hypervisor drivers don't have to repeat the same logic. But looks like a good start for a useful addition. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org