On 1/24/23 20:45, Sean Christopherson wrote:
Use a common X86_FEATURE_* flag for AMD's PSFD, and suppress it from
/proc/cpuinfo via the standard method of an empty string instead of
hacking in a one-off "private" #define in KVM. The request that led to
KVM defining its own flag was really just that the feature not show up
in /proc/cpuinfo, and additional patches+discussions in the interim have
clarified that defining flags in cpufeatures.h purely so that KVM can
advertise features to userspace is ok so long as the kernel already uses
a word to track the associated CPUID leaf.
No functional change intended.
Link: https://lore.kernel.org/all/d1b1e0da-29f0-c443-6c86-9549bbe1c79d@xxxxxxxxxxx
Link: https://lore.kernel.org/all/YxGZH7aOXQF7Pu5q@xxxxxxxxxxx
Link: https://lore.kernel.org/all/Y3O7UYWfOLfJkwM%2F@xxxxxxx
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/kvm/cpuid.c | 8 +-------
2 files changed, 2 insertions(+), 7 deletions(-)
Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 61012476d66e..2acaebc7bb76 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -330,6 +330,7 @@
#define X86_FEATURE_VIRT_SSBD (13*32+25) /* Virtualized Speculative Store Bypass Disable */
#define X86_FEATURE_AMD_SSB_NO (13*32+26) /* "" Speculative Store Bypass is fixed in hardware. */
#define X86_FEATURE_CPPC (13*32+27) /* Collaborative Processor Performance Control */
+#define X86_FEATURE_AMD_PSFD (13*32+28) /* "" Predictive Store Forwarding Disable */
#define X86_FEATURE_BTC_NO (13*32+29) /* "" Not vulnerable to Branch Type Confusion */
#define X86_FEATURE_BRS (13*32+31) /* Branch Sampling available */
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 2a9f1e200dbc..fb2b0e3ecce1 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -59,12 +59,6 @@ u32 xstate_required_size(u64 xstate_bv, bool compacted)
return ret;
}
-/*
- * This one is tied to SSB in the user API, and not
- * visible in /proc/cpuinfo.
- */
-#define KVM_X86_FEATURE_AMD_PSFD (13*32+28) /* Predictive Store Forwarding Disable */
-
#define F feature_bit
/* Scattered Flag - For features that are scattered by cpufeatures.h. */
@@ -710,7 +704,7 @@ void kvm_set_cpu_caps(void)
F(CLZERO) | F(XSAVEERPTR) |
F(WBNOINVD) | F(AMD_IBPB) | F(AMD_IBRS) | F(AMD_SSBD) | F(VIRT_SSBD) |
F(AMD_SSB_NO) | F(AMD_STIBP) | F(AMD_STIBP_ALWAYS_ON) |
- __feature_bit(KVM_X86_FEATURE_AMD_PSFD)
+ F(AMD_PSFD)
);
/*
base-commit: 7cb79f433e75b05d1635aefaa851cfcd1cb7dc4f
