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| author | Sean Christopherson <seanjc@google.com> | 2023-06-06 17:46:36 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-06-13 09:09:07 -0700 |
| commit | a30642570855faa1992f333ce5cb60351b0a37da (patch) | |
| tree | fcfffb3d91d0edc466fef7bf7729d1974a75998c /arch/x86 | |
| parent | e12fa4b92a07f4274ffa02e581d059a7869dd50e (diff) | |
| download | linux-stable-a30642570855faa1992f333ce5cb60351b0a37da.tar.gz linux-stable-a30642570855faa1992f333ce5cb60351b0a37da.tar.bz2 linux-stable-a30642570855faa1992f333ce5cb60351b0a37da.zip | |
KVM: x86: Update comments about MSR lists exposed to userspace
Refresh comments about msrs_to_save, emulated_msrs, and msr_based_features
to remove stale references left behind by commit 2374b7310b66 (KVM:
x86/pmu: Use separate array for defining "PMU MSRs to save"), and to
better reflect the current reality, e.g. emulated_msrs is no longer just
for MSRs that are "kvm-specific".
Reported-by: Binbin Wu <binbin.wu@linux.intel.com>
Link: https://lore.kernel.org/r/20230607004636.1421424-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/x86.c | 27 |
1 files changed, 13 insertions, 14 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 355f3df8dbad..07b0f960de07 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1423,15 +1423,14 @@ int kvm_emulate_rdpmc(struct kvm_vcpu *vcpu) EXPORT_SYMBOL_GPL(kvm_emulate_rdpmc); /* - * List of msr numbers which we expose to userspace through KVM_GET_MSRS - * and KVM_SET_MSRS, and KVM_GET_MSR_INDEX_LIST. - * - * The three MSR lists(msrs_to_save, emulated_msrs, msr_based_features) - * extract the supported MSRs from the related const lists. - * msrs_to_save is selected from the msrs_to_save_all to reflect the - * capabilities of the host cpu. This capabilities test skips MSRs that are - * kvm-specific. Those are put in emulated_msrs_all; filtering of emulated_msrs - * may depend on host virtualization features rather than host cpu features. + * The three MSR lists(msrs_to_save, emulated_msrs, msr_based_features) track + * the set of MSRs that KVM exposes to userspace through KVM_GET_MSRS, + * KVM_SET_MSRS, and KVM_GET_MSR_INDEX_LIST. msrs_to_save holds MSRs that + * require host support, i.e. should be probed via RDMSR. emulated_msrs holds + * MSRs that KVM emulates without strictly requiring host support. + * msr_based_features holds MSRs that enumerate features, i.e. are effectively + * CPUID leafs. Note, msr_based_features isn't mutually exclusive with + * msrs_to_save and emulated_msrs. */ static const u32 msrs_to_save_base[] = { @@ -1527,11 +1526,11 @@ static const u32 emulated_msrs_all[] = { MSR_IA32_UCODE_REV, /* - * The following list leaves out MSRs whose values are determined - * by arch/x86/kvm/vmx/nested.c based on CPUID or other MSRs. - * We always support the "true" VMX control MSRs, even if the host - * processor does not, so I am putting these registers here rather - * than in msrs_to_save_all. + * KVM always supports the "true" VMX control MSRs, even if the host + * does not. The VMX MSRs as a whole are considered "emulated" as KVM + * doesn't strictly require them to exist in the host (ignoring that + * KVM would refuse to load in the first place if the core set of MSRs + * aren't supported). */ MSR_IA32_VMX_BASIC, MSR_IA32_VMX_TRUE_PINBASED_CTLS, |