>From 565a06e1d6e1ea40daa113bc2b3d10e7b2a8a508 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 18 Nov 2022 08:52:28 -0800 Subject: [PATCH 2/2] 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 --- arch/x86/kvm/cpuid.c | 8 ++++---- arch/x86/kvm/reverse_cpuid.h | 18 +++++++++++++++--- 2 files changed, 19 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index ff2e9734e5c1..73c3c6dc6e7b 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -549,9 +549,9 @@ static __always_inline void __kvm_cpu_cap_mask(unsigned int leaf) } static __always_inline -void kvm_cpu_cap_init_scattered(enum kvm_only_cpuid_leafs leaf, u32 mask) +void kvm_cpu_cap_init_kvm_defined(enum kvm_only_cpuid_leafs leaf, u32 mask) { - /* Use kvm_cpu_cap_mask for non-scattered leafs. */ + /* Use kvm_cpu_cap_mask for leafs that aren't KVM-only. */ BUILD_BUG_ON(leaf < NCAPINTS); kvm_cpu_caps[leaf] = mask; @@ -561,7 +561,7 @@ void kvm_cpu_cap_init_scattered(enum kvm_only_cpuid_leafs leaf, u32 mask) static __always_inline void kvm_cpu_cap_mask(enum cpuid_leafs leaf, u32 mask) { - /* Use kvm_cpu_cap_init_scattered for scattered leafs. */ + /* Use kvm_cpu_cap_init_kvm_defined for KVM-only leafs. */ BUILD_BUG_ON(leaf >= NCAPINTS); kvm_cpu_caps[leaf] &= mask; @@ -670,7 +670,7 @@ void kvm_set_cpu_caps(void) F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | F(XSAVES) | f_xfd ); - kvm_cpu_cap_init_scattered(CPUID_12_EAX, + kvm_cpu_cap_init_kvm_defined(CPUID_12_EAX, SF(SGX1) | SF(SGX2) ); 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 /* - * 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). */ -- 2.38.1.584.g0f3c55d4c2-goog