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authorSean Christopherson <seanjc@google.com>2022-11-25 15:58:39 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2022-11-28 21:33:26 +0300
commit047c7229906152fb85c23dc18fd25a00cd7cb4de (patch)
tree3148f374e5c924f1e2f289dd8b3bac324d22a54d /arch/x86/kvm/reverse_cpuid.h
parentc4690d016182d271a862767145db8b2bc792f4a8 (diff)
downloadlinux-047c7229906152fb85c23dc18fd25a00cd7cb4de.tar.xz
KVM: x86: Update KVM-only leaf handling to allow for 100% KVM-only leafs
Rename kvm_cpu_cap_init_scattered() to kvm_cpu_cap_init_kvm_defined() in anticipation of adding KVM-only CPUID leafs that aren't recognized by the kernel and thus not scattered, i.e. for leafs that are 100% KVM-defined. Adjust/add comments to kvm_only_cpuid_leafs and KVM_X86_FEATURE to document how to create new kvm_only_cpuid_leafs entries for scattered features as well as features that are entirely unknown to the kernel. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20221125125845.1182922-3-jiaxi.chen@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/reverse_cpuid.h')
-rw-r--r--arch/x86/kvm/reverse_cpuid.h18
1 files changed, 15 insertions, 3 deletions
diff --git a/arch/x86/kvm/reverse_cpuid.h b/arch/x86/kvm/reverse_cpuid.h
index a19d473d0184..443a6b3e66c0 100644
--- a/arch/x86/kvm/reverse_cpuid.h
+++ b/arch/x86/kvm/reverse_cpuid.h
@@ -7,9 +7,9 @@
#include <asm/cpufeatures.h>
/*
- * Hardware-defined CPUID leafs that are scattered in the kernel, but need to
- * be directly used by KVM. Note, these word values conflict with the kernel's
- * "bug" caps, but KVM doesn't use those.
+ * Hardware-defined CPUID leafs that are either scattered by the kernel or are
+ * unknown to the kernel, but need to be directly used by KVM. Note, these
+ * word values conflict with the kernel's "bug" caps, but KVM doesn't use those.
*/
enum kvm_only_cpuid_leafs {
CPUID_12_EAX = NCAPINTS,
@@ -18,6 +18,18 @@ enum kvm_only_cpuid_leafs {
NKVMCAPINTS = NR_KVM_CPU_CAPS - NCAPINTS,
};
+/*
+ * Define a KVM-only feature flag.
+ *
+ * For features that are scattered by cpufeatures.h, __feature_translate() also
+ * needs to be updated to translate the kernel-defined feature into the
+ * KVM-defined feature.
+ *
+ * For features that are 100% KVM-only, i.e. not defined by cpufeatures.h,
+ * forego the intermediate KVM_X86_FEATURE and directly define X86_FEATURE_* so
+ * that X86_FEATURE_* can be used in KVM. No __feature_translate() handling is
+ * needed in this case.
+ */
#define KVM_X86_FEATURE(w, f) ((w)*32 + (f))
/* Intel-defined SGX sub-features, CPUID level 0x12 (EAX). */