[libvirt] [PATCH v2 04/23] qemu: Forbid config when topology based cpu count doesn't match the config
John Ferlan
jferlan at redhat.com
Fri Aug 19 17:10:09 UTC 2016
On 08/19/2016 10:38 AM, Peter Krempa wrote:
> As of qemu commit:
> commit a32ef3bfc12c8d0588f43f74dcc5280885bbdb30
> Author: Thomas Huth <thuth at redhat.com>
> Date: Wed Jul 22 15:59:50 2015 +0200
>
> vl: Add another sanity check to smp_parse() function
>
> v2.4.0-952-ga32ef3b
>
> configuration where the maximum CPU count doesn't match the topology is
> rejected. Prior to that only configurations where the topology would
> contain more cpus than the maximum count would be rejected.
>
> Use QEMU_CAPS_QUERY_HOTPLUGGABLE_CPUS as a relevant recent enough
> witness to avoid breaking old configs.
> ---
>
> Notes:
> v2:
> -fixed typo in commit message
> - already ACKed
>
> src/qemu/qemu_domain.c | 38 ++++++++++++++++++++++++++++++++------
> 1 file changed, 32 insertions(+), 6 deletions(-)
>
> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> index 4b8c878..c56dc75 100644
> --- a/src/qemu/qemu_domain.c
> +++ b/src/qemu/qemu_domain.c
> @@ -2314,12 +2314,21 @@ qemuDomainDefPostParse(virDomainDefPtr def,
> static int
> qemuDomainDefValidate(const virDomainDef *def,
> virCapsPtr caps ATTRIBUTE_UNUSED,
> - void *opaque ATTRIBUTE_UNUSED)
> + void *opaque)
> {
> + virQEMUDriverPtr driver = opaque;
> + virQEMUCapsPtr qemuCaps = NULL;
> + size_t topologycpus;
> + int ret = -1;
> +
> + if (!(qemuCaps = virQEMUCapsCacheLookup(driver->qemuCapsCache,
> + def->emulator)))
> + goto cleanup;
> +
> if (def->mem.min_guarantee) {
> virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> _("Parameter 'min_guarantee' not supported by QEMU."));
> - return -1;
> + goto cleanup;
> }
>
> if (def->os.loader &&
> @@ -2330,7 +2339,7 @@ qemuDomainDefValidate(const virDomainDef *def,
> if (!qemuDomainMachineIsQ35(def)) {
> virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> _("Secure boot is supported with q35 machine types only"));
> - return -1;
> + goto cleanup;
> }
>
> /* Now, technically it is possible to have secure boot on
> @@ -2339,17 +2348,34 @@ qemuDomainDefValidate(const virDomainDef *def,
> if (def->os.arch != VIR_ARCH_X86_64) {
> virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> _("Secure boot is supported for x86_64 architecture only"));
> - return -1;
> + goto cleanup;
> }
>
> if (def->features[VIR_DOMAIN_FEATURE_SMM] != VIR_TRISTATE_SWITCH_ON) {
> virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> _("Secure boot requires SMM feature enabled"));
> - return -1;
> + goto cleanup;
> }
> }
>
> - return 0;
> + /* qemu as of 2.5.0 rejects SMP topologies that don't match the cpu count */
> + if (def->cpu && def->cpu->sockets) {
> + topologycpus = def->cpu->sockets * def->cpu->cores * def->cpu->threads;
> + if (topologycpus != virDomainDefGetVcpusMax(def)) {
> + /* presence of query-hotpluggable-cpus should be a good enough witness */
> + if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_QUERY_HOTPLUGGABLE_CPUS)) {
> + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> + _("CPU topology doesn't match maximum vcpu count"));
> + goto cleanup;
> + }
Would it be a good idea to add a VIR_WARN or VIR_INFO (something) that
will give a heads up that the configuration may prevent some future
start? Especially since you went through all the math before detecting
the capability...
John
> + }
> + }
> +
> + ret = 0;
> +
> + cleanup:
> + virObjectUnref(qemuCaps);
> + return ret;
> }
>
>
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