[PATCH v9 06/17] KVM: x86: Add Arch LBR MSRs to msrs_to_save_all list

Yang Weijiang
2022-02-16T10:27:18Z

Arch LBR MSR_ARCH_LBR_DEPTH and MSR_ARCH_LBR_CTL are queried by
userspace application before it wants to {save|restore} the Arch LBR
data. Other LBR related data MSRs are omitted here intentionally due
to lengthy list(32*3). Userspace can still use KVM_{GET|SET}_MSRS to
access them if necessary.

Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
---
arch/x86/kvm/x86.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8891329d594c..5d8a0364a3cc 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1394,6 +1394,7 @@ static const u32 msrs_to_save_all[] = {
MSR_F15H_PERF_CTR3, MSR_F15H_PERF_CTR4, MSR_F15H_PERF_CTR5,
MSR_IA32_XFD, MSR_IA32_XFD_ERR,
MSR_IA32_XSS,
+ MSR_ARCH_LBR_CTL, MSR_ARCH_LBR_DEPTH,
};

static u32 msrs_to_save[ARRAY_SIZE(msrs_to_save_all)];
@@ -6634,6 +6635,11 @@ static void kvm_init_msr_list(void)
if (!supported_xss)
continue;
break;
+ case MSR_ARCH_LBR_DEPTH:
+ case MSR_ARCH_LBR_CTL:
+ if (!kvm_cpu_cap_has(X86_FEATURE_ARCH_LBR))
+ continue;
+ break;
default:
break;
}
--
2.27.0