[v2] qemu: Relax hyperv features validation

[PATCH v2 1/2] qemu_validate: Drop VIR_DOMAIN_HYPERV_SYNIC dependency on VIR_DOMAIN_HYPERV_VPINDEX

Posted by Michal Privoznik via Devel 3 weeks, 5 days ago

From: Michal Privoznik <mprivozn@redhat.com>

Turns out, that synic hyperv enlightenment not always requires
vpindex. Some (older) machine types (e.g. pc-i440fx-3.0,
pc-q35-3.0, pc-i440fx-rhel7.6.0) can run with synic enabled and vpindex
disabled. This is because they did enable 'x-hv-synic-kvm-only'
CPU property, but starting from QEMU commit v3.1.0-rc0~44^2~9 the
property is disabled by default.

To avoid parsing machine type version, let's just drop this
dependency validation and rely on QEMU to report sensible error
message.

Resolves: https://gitlab.com/libvirt/libvirt/-/issues/837
Resolves: https://issues.redhat.com/browse/RHEL-138689
Fixes: 1822d030c32d9857020ee8385b0a8808a29a472f
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
 src/qemu/qemu_validate.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/qemu/qemu_validate.c b/src/qemu/qemu_validate.c
index da08fd17cd..3e27c11da3 100644
--- a/src/qemu/qemu_validate.c
+++ b/src/qemu/qemu_validate.c
@@ -112,8 +112,6 @@ qemuValidateDomainDefHypervFeatures(const virDomainDef *def)
         return -1;
     }
 
-    CHECK_HV_FEAT(VIR_DOMAIN_HYPERV_SYNIC, VIR_DOMAIN_HYPERV_VPINDEX);
-
     if (def->hyperv.features[VIR_DOMAIN_HYPERV_STIMER] == VIR_TRISTATE_SWITCH_ON) {
         if (!virDomainDefHasTimer(def, VIR_DOMAIN_TIMER_NAME_HYPERVCLOCK)) {
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
-- 
2.52.0

Re: [PATCH v2 1/2] qemu_validate: Drop VIR_DOMAIN_HYPERV_SYNIC dependency on VIR_DOMAIN_HYPERV_VPINDEX

Posted by Daniel P. Berrangé via Devel 3 weeks, 5 days ago

On Tue, Jan 06, 2026 at 05:57:45PM +0100, Michal Privoznik via Devel wrote:
> From: Michal Privoznik <mprivozn@redhat.com>
> 
> Turns out, that synic hyperv enlightenment not always requires
> vpindex. Some (older) machine types (e.g. pc-i440fx-3.0,
> pc-q35-3.0, pc-i440fx-rhel7.6.0) can run with synic enabled and vpindex
> disabled. This is because they did enable 'x-hv-synic-kvm-only'
> CPU property, but starting from QEMU commit v3.1.0-rc0~44^2~9 the
> property is disabled by default.
> 
> To avoid parsing machine type version, let's just drop this
> dependency validation and rely on QEMU to report sensible error
> message.
> 
> Resolves: https://gitlab.com/libvirt/libvirt/-/issues/837
> Resolves: https://issues.redhat.com/browse/RHEL-138689
> Fixes: 1822d030c32d9857020ee8385b0a8808a29a472f
> Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
> ---
>  src/qemu/qemu_validate.c | 2 --
>  1 file changed, 2 deletions(-)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>


With regards,
Daniel
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[PATCH v2 1/2] qemu_validate: Drop VIR_DOMAIN_HYPERV_SYNIC dependency on VIR_DOMAIN_HYPERV_VPINDEX
[PATCH v2 2/2] qemu_validate: Drop VIR_DOMAIN_HYPERV_STIMER dependency on VIR_DOMAIN_HYPERV_VPINDEX