diff options
| author | Sean Christopherson <seanjc@google.com> | 2023-08-15 13:36:39 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-08-17 11:38:27 -0700 |
| commit | 42764413d19585caff1321823b376c0bd0a597af (patch) | |
| tree | 2d89a7883e9b16f00a5f2377eb1278ef6496df41 /arch/x86/kvm/cpuid.c | |
| parent | 392a53246257a9f89ef421b60af62056ce374285 (diff) | |
KVM: x86: Add a framework for enabling KVM-governed x86 features
Introduce yet another X86_FEATURE flag framework to manage and cache KVM
governed features (for lack of a better name). "Governed" in this case
means that KVM has some level of involvement and/or vested interest in
whether or not an X86_FEATURE can be used by the guest. The intent of the
framework is twofold: to simplify caching of guest CPUID flags that KVM
needs to frequently query, and to add clarity to such caching, e.g. it
isn't immediately obvious that SVM's bundle of flags for "optional nested
SVM features" track whether or not a flag is exposed to L1.
Begrudgingly define KVM_MAX_NR_GOVERNED_FEATURES for the size of the
bitmap to avoid exposing governed_features.h in arch/x86/include/asm/, but
add a FIXME to call out that it can and should be cleaned up once
"struct kvm_vcpu_arch" is no longer expose to the kernel at large.
Cc: Zeng Guang <guang.zeng@intel.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/r/20230815203653.519297-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm/cpuid.c')
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 5a88affb2e1a..4ba43ae008cb 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -313,6 +313,10 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) struct kvm_lapic *apic = vcpu->arch.apic; struct kvm_cpuid_entry2 *best; + BUILD_BUG_ON(KVM_NR_GOVERNED_FEATURES > KVM_MAX_NR_GOVERNED_FEATURES); + bitmap_zero(vcpu->arch.governed_features.enabled, + KVM_MAX_NR_GOVERNED_FEATURES); + best = kvm_find_cpuid_entry(vcpu, 1); if (best && apic) { if (cpuid_entry_has(best, X86_FEATURE_TSC_DEADLINE_TIMER)) |