[PATCH v2 2/4] qemu: avoid launching non-x86 guests with 'pvspinlock' setting

[Daniel Henrique Barboza <danielhb413@xxxxxxxxx>]

The 'pvspinlock' feature is x86 only. The "<pvspinlock/>" declaration
will always have a value 'on' or 'off', and both will break QEMU when
launching non-x86 guests. This is the error message for
"<pvspinlock state='on'/>" when running a ppc64 guest:

qemu-kvm: Expected key=value format, found +kvm_pv_unhalt

A similar error message is thrown for "<pvspinlock state='off'/>".

This patch prevents non-x86 guests from launching with any
pvspinlock setting with a more informative error message:

error: unsupported configuration: The 'pvspinlock' feature is not
supported for architecture 'ppc64' or machine type 'pseries'

Suggested-by: Andrea Bolognani <abologna@xxxxxxxxxx>
Signed-off-by: Daniel Henrique Barboza <danielhb413@xxxxxxxxx>
---
 src/qemu/qemu_domain.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 73a65128c6..c56b3a893b 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -5271,13 +5271,25 @@ qemuDomainDefValidateFeatures(const virDomainDef *def,
             }
             break;
 
+        case VIR_DOMAIN_FEATURE_PVSPINLOCK:
+            if (def->features[i] != VIR_TRISTATE_SWITCH_ABSENT &&
+                !ARCH_IS_X86(def->os.arch)) {
+                virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                               _("The '%s' feature is not supported for "
+                                 "architecture '%s' or machine type '%s'"),
+                                 featureName,
+                                 virArchToString(def->os.arch),
+                                 def->os.machine);
+                 return -1;
+            }
+            break;
+
         case VIR_DOMAIN_FEATURE_ACPI:
         case VIR_DOMAIN_FEATURE_PAE:
         case VIR_DOMAIN_FEATURE_HAP:
         case VIR_DOMAIN_FEATURE_VIRIDIAN:
         case VIR_DOMAIN_FEATURE_PRIVNET:
         case VIR_DOMAIN_FEATURE_HYPERV:
-        case VIR_DOMAIN_FEATURE_PVSPINLOCK:
         case VIR_DOMAIN_FEATURE_CAPABILITIES:
         case VIR_DOMAIN_FEATURE_PMU:
         case VIR_DOMAIN_FEATURE_MSRS:
-- 
2.25.1