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| author | David Dunn <daviddunn@google.com> | 2022-02-23 23:57:41 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-02-25 14:20:14 +0100 |
| commit | ba7bb663f5547ef474c98df99a97bb4a13c5715f (patch) | |
| tree | edf880ca47225e0903485a4ff16a55824152cdd8 /Documentation/virt | |
| parent | KVM: x86: Fix pointer mistmatch warning when patching RET0 static calls (diff) | |
| download | linux-ba7bb663f5547ef474c98df99a97bb4a13c5715f.tar.xz linux-ba7bb663f5547ef474c98df99a97bb4a13c5715f.zip | |
KVM: x86: Provide per VM capability for disabling PMU virtualization
Add a new capability, KVM_CAP_PMU_CAPABILITY, that takes a bitmask of
settings/features to allow userspace to configure PMU virtualization on
a per-VM basis. For now, support a single flag, KVM_PMU_CAP_DISABLE,
to allow disabling PMU virtualization for a VM even when KVM is configured
with enable_pmu=true a module level.
To keep KVM simple, disallow changing VM's PMU configuration after vCPUs
have been created.
Signed-off-by: David Dunn <daviddunn@google.com>
Message-Id: <20220223225743.2703915-2-daviddunn@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation/virt')
| -rw-r--r-- | Documentation/virt/kvm/api.rst | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index c3e68c1531f0..f5d011351016 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -7643,3 +7643,25 @@ The argument to KVM_ENABLE_CAP is also a bitmask, and must be a subset of the result of KVM_CHECK_EXTENSION. KVM will forward to userspace the hypercalls whose corresponding bit is in the argument, and return ENOSYS for the others. + +8.35 KVM_CAP_PMU_CAPABILITY +--------------------------- + +:Capability KVM_CAP_PMU_CAPABILITY +:Architectures: x86 +:Type: vm +:Parameters: arg[0] is bitmask of PMU virtualization capabilities. +:Returns 0 on success, -EINVAL when arg[0] contains invalid bits + +This capability alters PMU virtualization in KVM. + +Calling KVM_CHECK_EXTENSION for this capability returns a bitmask of +PMU virtualization capabilities that can be adjusted on a VM. + +The argument to KVM_ENABLE_CAP is also a bitmask and selects specific +PMU virtualization capabilities to be applied to the VM. This can +only be invoked on a VM prior to the creation of VCPUs. + +At this time, KVM_PMU_CAP_DISABLE is the only capability. Setting +this capability will disable PMU virtualization for that VM. Usermode +should adjust CPUID leaf 0xA to reflect that the PMU is disabled. |