From: Josh Poimboeuf Date: Fri, 25 Aug 2023 07:01:35 +0000 (-0700) Subject: KVM: x86: Add IBPB_BRTYPE support X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=6f0f23ef76be11bc6ace10df5e807f3542da8772;p=linux.git KVM: x86: Add IBPB_BRTYPE support Add support for the IBPB_BRTYPE CPUID flag, which indicates that IBPB includes branch type prediction flushing. Note, like SRSO_NO, advertise support for IBPB_BRTYPE even if it's not enumerated by in the raw CPUID, i.e. bypass the cpuid_count() in __kvm_cpu_cap_mask(). Some CPUs that gained support via a uCode patch don't report IBPB_BRTYPE via CPUID (the kernel forces the flag). Opportunistically use kvm_cpu_cap_check_and_set() for SRSO_NO instead of manually querying host support (cpu_feature_enabled() and boot_cpu_has() yield the same end result in this case). Signed-off-by: Josh Poimboeuf Link: https://lore.kernel.org/r/79d5f5914fb42c2c62418ffbcd78f138645ded21.1692919072.git.jpoimboe@kernel.org Signed-off-by: Sean Christopherson --- diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 0544e30b4946d..8f26a929d510c 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -764,8 +764,8 @@ void kvm_set_cpu_caps(void) F(NULL_SEL_CLR_BASE) | F(AUTOIBRS) | 0 /* PrefetchCtlMsr */ ); - if (cpu_feature_enabled(X86_FEATURE_SRSO_NO)) - kvm_cpu_cap_set(X86_FEATURE_SRSO_NO); + kvm_cpu_cap_check_and_set(X86_FEATURE_IBPB_BRTYPE); + kvm_cpu_cap_check_and_set(X86_FEATURE_SRSO_NO); kvm_cpu_cap_init_kvm_defined(CPUID_8000_0022_EAX, F(PERFMON_V2)