Re: [libvirt] [PATCH 08/11] qemu: Fix GIC behavior for the default case
On 02/06/2018 11:42 AM, Andrea Bolognani wrote:
When no GIC version is specified, we currently default to GIC v2;
however, that's not a great default, since guests will fail to
start if the hardware only supports GIC v3.
Change the behavior so that a sensible default is chosen instead.
That basically means using the same algorithm whether the user
didn't explicitly enable the GIC feature or they explicitly
enabled it but didn't specify any GIC version.
Signed-off-by: Andrea Bolognani <abologna(a)redhat.com>
---
src/qemu/qemu_domain.c | 25 +++++++++++-----------
.../qemuxml2argvdata/aarch64-gic-default-both.args | 2 +-
tests/qemuxml2argvdata/aarch64-gic-default-v3.args | 2 +-
.../aarch64-gic-default-both.xml | 2 +-
.../qemuxml2xmloutdata/aarch64-gic-default-v3.xml | 2 +-
5 files changed, 17 insertions(+), 16 deletions(-)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 98cba8789..ee720d328 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -2838,13 +2838,14 @@ static void
qemuDomainDefEnableDefaultFeatures(virDomainDefPtr def,
virQEMUCapsPtr qemuCaps)
{
- virGICVersion version;
-
- /* The virt machine type always uses GIC: if the relevant element
+ /* The virt machine type always uses GIC: if the relevant information
* was not included in the domain XML, we need to choose a suitable
* GIC version ourselves */
- if (def->features[VIR_DOMAIN_FEATURE_GIC] == VIR_TRISTATE_SWITCH_ABSENT
&&
- qemuDomainIsVirt(def)) {
+ if ((def->features[VIR_DOMAIN_FEATURE_GIC] == VIR_TRISTATE_SWITCH_ABSENT
&&
+ qemuDomainIsVirt(def)) ||
+ (def->features[VIR_DOMAIN_FEATURE_GIC] == VIR_TRISTATE_SWITCH_ON &&
And patch3 (e.g. verification) takes care of us if this is "on", but
!qemuDomainIsVirt(def) ends up being true... It's a tangled web.
+ def->gic_version == VIR_GIC_VERSION_NONE)) {
+ virGICVersion version;
VIR_DEBUG("Looking for usable GIC version in domain capabilities");
for (version = VIR_GIC_VERSION_LAST - 1;
@@ -2878,17 +2879,17 @@ qemuDomainDefEnableDefaultFeatures(virDomainDefPtr def,
}
}
FWIW: There's a hunk above here which notes something about bz
1414081... If one goes and reads that bz, one finds it's closed notabug.
In any case, there's a lot of verbiage there.. Can any of it be shaved?
What's being done seems reasonable, but if we can take the opportunity
to revisit the comment as well - that'd be good.
For what's here as long as the above comment doesn't cause you to have
an oh sh* moment...
Reviewed-by: John Ferlan <jferlan(a)redhat.com>
John
+ /* Use the default GIC version (GICv2) as a last-ditch
attempt
+ * if no match could be found above */
+ if (def->gic_version == VIR_GIC_VERSION_NONE) {
+ VIR_DEBUG("Using GIC version 2 (default)");
+ def->gic_version = VIR_GIC_VERSION_2;
+ }
+
/* Even if we haven't found a usable GIC version in the domain
* capabilities, we still want to enable this */
def->features[VIR_DOMAIN_FEATURE_GIC] = VIR_TRISTATE_SWITCH_ON;
}
-
- /* Use the default GIC version (GICv2) if no version was specified */
- if (def->features[VIR_DOMAIN_FEATURE_GIC] == VIR_TRISTATE_SWITCH_ON &&
- def->gic_version == VIR_GIC_VERSION_NONE) {
- VIR_DEBUG("Using GIC version 2 (default)");
- def->gic_version = VIR_GIC_VERSION_2;
- }
}
[...]