[PATCH v8 3/8] x86/cpu, kvm: Add the NO_NESTED_DATA_BP feature

Kim Phillips
2023-01-23T22:58:23Z

The "Processor ignores nested data breakpoints" feature was being
open-coded for KVM. Add the feature to its newly introduced
CPUID leaf 0x80000021 EAX proper.

Signed-off-by: Kim Phillips <kim.phillips@amd.com>
---
arch/x86/include/asm/cpufeatures.h | 3 +++
arch/x86/kvm/cpuid.c | 2 +-
2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index a84536876794..7f0fb894e432 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -428,6 +428,9 @@
#define X86_FEATURE_V_TSC_AUX (19*32+ 9) /* "" Virtual TSC_AUX */
#define X86_FEATURE_SME_COHERENT (19*32+10) /* "" AMD hardware-enforced cache coherency */

+/* AMD-defined Extended Feature 2 EAX, CPUID level 0x80000021 (EAX), word 20 */
+#define X86_FEATURE_NO_NESTED_DATA_BP (20*32+ 0) /* "" No Nested Data Breakpoints */
+
/*
* BUG word(s)
*/
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 3930452bf06e..13bd2769fa5a 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -742,7 +742,7 @@ void kvm_set_cpu_caps(void)
F(SME_COHERENT));

kvm_cpu_cap_mask(CPUID_8000_0021_EAX,
- BIT(0) /* NO_NESTED_DATA_BP */ | 0 /* SmmPgCfgLock */ |
+ F(NO_NESTED_DATA_BP) | 0 /* SmmPgCfgLock */ |
BIT(6) /* NULL_SEL_CLR_BASE */ | 0 /* PrefetchCtlMsr */
);
if (cpu_feature_enabled(X86_FEATURE_LFENCE_RDTSC))
--
2.34.1