[libvirt PATCH v2 10/14] Document specifics of virConnectBaselineHypervisorCPU

Jiri Denemark jdenemar at redhat.com
Fri Oct 7 17:21:47 UTC 2022

The API can be used to get usability blockers for an unusable CPU model,
which is not obvious. Let's explicitly document this behavior as it is
now mentioned in the documentation of domain capabilities XML.

Signed-off-by: Jiri Denemark <jdenemar at redhat.com>

    Version 2:
    - new patch

 src/libvirt-host.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/libvirt-host.c b/src/libvirt-host.c
index 2ee6370bce..c02222346c 100644
--- a/src/libvirt-host.c
+++ b/src/libvirt-host.c
@@ -1319,6 +1319,15 @@ virConnectBaselineCPU(virConnectPtr conn,
  * This is different from virConnectBaselineCPU() which doesn't consider any
  * hypervisor abilities when computing the best CPU.
+ * If @ncpus == 1, the result will be the first (and only) CPU in @xmlCPUs
+ * tailored to what the hypervisor can support on the current host.
+ * Specifically if this single CPU definition contains no feature elements and
+ * a CPU model listed as usable='no' in domain capabilities XML, the result
+ * will contain a list usability blockers, i.e., a list of features that would
+ * need to be disabled to for the model to be usable on this host. This list
+ * may contain more features than what the hypervisor reports as blockers in
+ * case the CPU model definition in libvirt differs from QEMU definition.
+ *
  * If @flags includes VIR_CONNECT_BASELINE_CPU_EXPAND_FEATURES then libvirt
  * will explicitly list all CPU features that are part of the computed CPU,
  * without this flag features that are part of the CPU model will not be

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