[libvirt] [PATCH] s390: qemu-capabilities: Avoid error message when missing non-kvm host cpu info

Jiri Denemark jdenemar at redhat.com
Fri Nov 24 15:56:55 UTC 2017


On Fri, Nov 24, 2017 at 09:02:02 +0100, Boris Fiuczynski wrote:
> From: "Jason J. Herne" <jjherne at linux.vnet.ibm.com>
> 
> Libvirt prints an error on startup when it is missing host cpu model
> information for any queried qemu binary. On s390 we only have host cpu model
> information for kvm enabled qemu instances. So when virt type is not kvm, this
> is actually not an error on s390.
> 
> This patch adds virt type as a parameter to virQEMUCapsInitCPUModelS390, and a
> new return code 2 for virQEMUCapsInitCPUModel and virQEMUCapsInitCPUModelS390.
> If the virt type is not kvm then we skip printing the scary error message
> and return 2 because this case is actually expected behavior. The new return
> code is meant to differentiate between the failure case and the case where we
> simply expect the cpu model information to be unattainable.
> 
> Signed-off-by: Jason J. Herne <jjherne at linux.vnet.ibm.com>
> Reviewed-by: Boris Fiuczynski <fiuczy at linux.vnet.ibm.com>
> Reviewed-by: Marc Hartmayer <mhartmay at linux.vnet.ibm.com>
> ---
>  src/qemu/qemu_capabilities.c | 30 ++++++++++++++++++++++--------
>  1 file changed, 22 insertions(+), 8 deletions(-)
> 
> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> index 3adea66..b073841 100644
> --- a/src/qemu/qemu_capabilities.c
> +++ b/src/qemu/qemu_capabilities.c
> @@ -3306,22 +3306,28 @@ virQEMUCapsCPUFilterFeatures(const char *name,
>  /**
>   * Returns  0 when host CPU model provided by QEMU was filled in qemuCaps,
>   *          1 when the caller should fall back to using virCapsPtr->host.cpu,
> + *          2 when cpu model info is not supported for this configuration and
> + *            fall back should not be used.
>   *         -1 on error.
>   */
>  static int
>  virQEMUCapsInitCPUModelS390(virQEMUCapsPtr qemuCaps,
>                              qemuMonitorCPUModelInfoPtr modelInfo,
>                              virCPUDefPtr cpu,
> -                            bool migratable)
> +                            bool migratable,
> +                            virDomainVirtType type)

virQEMUCapsInitCPUModelX86 is declared with 'type' being the second
parameter. Let's make it consistent.

>  {
>      size_t i;
>  
>      if (!modelInfo) {
> -        virReportError(VIR_ERR_INTERNAL_ERROR,
> -                       _("missing host CPU model info from QEMU capabilities "
> -                         "for binary %s"),
> -                       qemuCaps->binary);
> -        return -1;
> +        if (type == VIR_DOMAIN_VIRT_KVM) {
> +            virReportError(VIR_ERR_INTERNAL_ERROR,
> +                           _("missing host CPU model info from QEMU "
> +                             "capabilities for binary %s"),
> +                           qemuCaps->binary);
> +            return -1;
> +        }
> +        return 2;
>      }
>  
>      if (VIR_STRDUP(cpu->model, modelInfo->name) < 0 ||
> @@ -3429,6 +3435,8 @@ virQEMUCapsInitCPUModelX86(virQEMUCapsPtr qemuCaps,
>  /**
>   * Returns  0 when host CPU model provided by QEMU was filled in qemuCaps,
>   *          1 when the caller should fall back to other methods
> + *          2 when cpu model info is not supported for this configuration and
> + *            fall back should not be used.
>   *         -1 on error.
>   */
>  int
> @@ -3445,13 +3453,13 @@ virQEMUCapsInitCPUModel(virQEMUCapsPtr qemuCaps,
>  
>      if (ARCH_IS_S390(qemuCaps->arch)) {
>          ret = virQEMUCapsInitCPUModelS390(qemuCaps, cpuData->info,
> -                                          cpu, migratable);
> +                                          cpu, migratable, type);

This would need to be adjusted, of course.

>      } else if (ARCH_IS_X86(qemuCaps->arch)) {
>          ret = virQEMUCapsInitCPUModelX86(qemuCaps, type, cpuData->info,
>                                           cpu, migratable);
>      }
>  
> -    if (ret == 0)
> +    if (ret == 0 || ret == 2)

This does not make sense. The cpu is not filled in by QEMU and thus
fallback should not be set to "forbid". Not to mention the caller will
just free the cpu structure anyway.

>          cpu->fallback = VIR_CPU_FALLBACK_FORBID;
>  
>      return ret;
> @@ -3504,6 +3512,12 @@ virQEMUCapsInitHostCPUModel(virQEMUCapsPtr qemuCaps,
>                                       virQEMUCapsCPUFilterFeatures,
>                                       &qemuCaps->arch) < 0)
>              goto error;
> +    } else if (rc == 2) {
> +        VIR_DEBUG("Qemu does not provide cpu model for arch=%s virttype=%s",

s/Qemu/QEMU/; s/cpu/CPU/

> +                  virArchToString(qemuCaps->arch),
> +                  virDomainVirtTypeToString(type));
> +        virCPUDefFree(cpu);
> +        goto cleanup;

And I'd just jump to the 'error' label instead of freeing cpu here.

>      } else if (type == VIR_DOMAIN_VIRT_KVM &&
>                 virCPUGetHostIsSupported(qemuCaps->arch)) {
>          if (!(fullCPU = virCPUGetHost(qemuCaps->arch, VIR_CPU_TYPE_GUEST,

ACK with the suggested nits fixed. I pushed the patch with the following
diff squashed in.

Thanks.

Jirka


diff --git i/src/qemu/qemu_capabilities.c w/src/qemu/qemu_capabilities.c
index b073841e8b..201e83c45c 100644
--- i/src/qemu/qemu_capabilities.c
+++ w/src/qemu/qemu_capabilities.c
@@ -3312,10 +3312,10 @@ virQEMUCapsCPUFilterFeatures(const char *name,
  */
 static int
 virQEMUCapsInitCPUModelS390(virQEMUCapsPtr qemuCaps,
+                            virDomainVirtType type,
                             qemuMonitorCPUModelInfoPtr modelInfo,
                             virCPUDefPtr cpu,
-                            bool migratable,
-                            virDomainVirtType type)
+                            bool migratable)
 {
     size_t i;
 
@@ -3452,14 +3452,14 @@ virQEMUCapsInitCPUModel(virQEMUCapsPtr qemuCaps,
         return 1;
 
     if (ARCH_IS_S390(qemuCaps->arch)) {
-        ret = virQEMUCapsInitCPUModelS390(qemuCaps, cpuData->info,
-                                          cpu, migratable, type);
+        ret = virQEMUCapsInitCPUModelS390(qemuCaps, type, cpuData->info,
+                                          cpu, migratable);
     } else if (ARCH_IS_X86(qemuCaps->arch)) {
         ret = virQEMUCapsInitCPUModelX86(qemuCaps, type, cpuData->info,
                                          cpu, migratable);
     }
 
-    if (ret == 0 || ret == 2)
+    if (ret == 0)
         cpu->fallback = VIR_CPU_FALLBACK_FORBID;
 
     return ret;
@@ -3513,11 +3513,10 @@ virQEMUCapsInitHostCPUModel(virQEMUCapsPtr qemuCaps,
                                      &qemuCaps->arch) < 0)
             goto error;
     } else if (rc == 2) {
-        VIR_DEBUG("Qemu does not provide cpu model for arch=%s virttype=%s",
+        VIR_DEBUG("QEMU does not provide CPU model for arch=%s virttype=%s",
                   virArchToString(qemuCaps->arch),
                   virDomainVirtTypeToString(type));
-        virCPUDefFree(cpu);
-        goto cleanup;
+        goto error;
     } else if (type == VIR_DOMAIN_VIRT_KVM &&
                virCPUGetHostIsSupported(qemuCaps->arch)) {
         if (!(fullCPU = virCPUGetHost(qemuCaps->arch, VIR_CPU_TYPE_GUEST,




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