Commit 047c7229 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

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: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20221125125845.1182922-3-jiaxi.chen@linux.intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent c4690d01

arch/x86/kvm/cpuid.c

+4 −4
Original line number Diff line number Diff line
@@ -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)

	);

arch/x86/kvm/reverse_cpuid.h

+15 −3
Original line number Diff line number Diff line
@@ -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). */