[libvirt PATCH 5/5] qemu: wire up support for maximum CPU model

[Pavel Hrdina]

On Tue, Feb 09, 2021 at 01:59:01PM +0000, Daniel P. Berrangé wrote:
> The "max" model can be treated the same way as "host" model in general.
> 
> Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
> ---
>  94 files changed, 431 insertions(+), 73 deletions(-)
> 
> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> index ecfb313d0a..58e28c3bd1 100644
> --- a/src/qemu/qemu_capabilities.c
> +++ b/src/qemu/qemu_capabilities.c
> @@ -2336,6 +2336,8 @@ virQEMUCapsIsCPUModeSupported(virQEMUCapsPtr qemuCaps,
>          return cpus && cpus->ncpus > 0;
>  
>      case VIR_CPU_MODE_MAXIMUM:
> +        return virQEMUCapsGet(qemuCaps, QEMU_CAPS_CPU_MAX);
> +
>      case VIR_CPU_MODE_LAST:
>          break;
>      }
> @@ -2985,7 +2987,7 @@ virQEMUCapsProbeQMPCPUDefinitions(virQEMUCapsPtr qemuCaps,
>                                    virQEMUCapsAccelPtr accel,
>                                    qemuMonitorPtr mon)
>  {
> -    qemuMonitorCPUDefsPtr defs = accel->cpuModels;
> +    qemuMonitorCPUDefsPtr defs;
>      size_t i;
>  
>      if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_QUERY_CPU_DEFINITIONS))
> @@ -2994,6 +2996,7 @@ virQEMUCapsProbeQMPCPUDefinitions(virQEMUCapsPtr qemuCaps,
>      if (virQEMUCapsFetchCPUDefinitions(mon, qemuCaps->arch, &accel->cpuModels) < 0)
>          return -1;
>  
> +    defs = accel->cpuModels;

And there is the fix for the crash from previous patch, so please do it
directly there.

>      for (i = 0; i < defs->ncpus; i++) {
>          if (STREQ_NULLABLE(defs->cpus[i].name, "max")) {
>              virQEMUCapsSet(qemuCaps, QEMU_CAPS_CPU_MAX);
> @@ -5977,6 +5980,18 @@ virQEMUCapsFillDomainCPUCaps(virQEMUCapsPtr qemuCaps,
>                                   VIR_TRISTATE_SWITCH_OFF);
>      }
>  
> +    if (virQEMUCapsIsCPUModeSupported(qemuCaps, hostarch, domCaps->virttype,
> +                                      VIR_CPU_MODE_MAXIMUM,
> +                                      domCaps->machine)) {
> +        domCaps->cpu.maximum = true;
> +
> +        domCaps->cpu.maximumMigratable.report = true;
> +        VIR_DOMAIN_CAPS_ENUM_SET(domCaps->cpu.maximumMigratable,
> +                                 VIR_TRISTATE_SWITCH_ON);
> +        VIR_DOMAIN_CAPS_ENUM_SET(domCaps->cpu.maximumMigratable,
> +                                 VIR_TRISTATE_SWITCH_OFF);
> +    }
> +
>      if (virQEMUCapsIsCPUModeSupported(qemuCaps, hostarch, domCaps->virttype,
>                                        VIR_CPU_MODE_HOST_MODEL,
>                                        domCaps->machine)) {

[...]

> diff --git a/src/qemu/qemu_validate.c b/src/qemu/qemu_validate.c
> index bf4ac19104..62a915e946 100644
> --- a/src/qemu/qemu_validate.c
> +++ b/src/qemu/qemu_validate.c
> @@ -255,10 +255,11 @@ qemuValidateDomainDefFeatures(const virDomainDef *def,
>  
>          case VIR_DOMAIN_FEATURE_KVM:
>              if (def->kvm_features[VIR_DOMAIN_KVM_DEDICATED] == VIR_TRISTATE_SWITCH_ON &&
> -                (!def->cpu || def->cpu->mode != VIR_CPU_MODE_HOST_PASSTHROUGH)) {
> +                (!def->cpu || (def->cpu->mode != VIR_CPU_MODE_HOST_PASSTHROUGH &&
> +                               def->cpu->mode != VIR_CPU_MODE_MAXIMUM))) {
>                  virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
>                                 _("kvm-hint-dedicated=on is only applicable "
> -                                 "for cpu host-passthrough"));
> +                                 "for cpu host-passthrough / maximum"));
>                  return -1;
>              }
>              break;
> @@ -396,7 +397,15 @@ qemuValidateDomainDefCpu(virQEMUDriverPtr driver,
>           * CUSTOM.
>           */
>          break;
> +
>      case VIR_CPU_MODE_MAXIMUM:
> +        if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_CPU_MAX)) {
> +            virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> +                           _("maximum CPU is not supported by QEMU binary"));

s/by QEMU/by this QEMU/

> +            return -1;
> +        }
> +        break;
> +
>      case VIR_CPU_MODE_CUSTOM:
>      case VIR_CPU_MODE_LAST:
>          break;

Otherwise looks good but it would need some changes if we do not trust
QEMU to behave the same way for kvm and tcg.

Pavel
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