Commit c2aa58b2 authored by Yang Weijiang's avatar Yang Weijiang Committed by Sean Christopherson
Browse files

KVM: x86: Add kvm_msr_{read,write}() helpers 



Wrap __kvm_{get,set}_msr() into two new helpers for KVM usage and use the
helpers to replace existing usage of the raw functions.
kvm_msr_{read,write}() are KVM-internal helpers, i.e. used when KVM needs
to get/set a MSR value for emulating CPU behavior, i.e., host_initiated ==
%true in the helpers.

Suggested-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarYang Weijiang <weijiang.yang@intel.com>
Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Tested-by: default avatarMathias Krause <minipli@grsecurity.net>
Tested-by: default avatarJohn Allen <john.allen@amd.com>
Signed-off-by: default avatarChao Gao <chao.gao@intel.com>
Tested-by: default avatarRick Edgecombe <rick.p.edgecombe@intel.com>
Link: https://lore.kernel.org/r/20250812025606.74625-4-chao.gao@intel.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent db07f3d0

arch/x86/include/asm/kvm_host.h

+2 −1
Original line number Diff line number Diff line
@@ -2156,9 +2156,10 @@ void kvm_enable_efer_bits(u64); 
bool kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer);

int kvm_emulate_msr_read(struct kvm_vcpu *vcpu, u32 index, u64 *data);

int kvm_emulate_msr_write(struct kvm_vcpu *vcpu, u32 index, u64 data);

int __kvm_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data, bool host_initiated);

int __kvm_emulate_msr_read(struct kvm_vcpu *vcpu, u32 index, u64 *data);

int __kvm_emulate_msr_write(struct kvm_vcpu *vcpu, u32 index, u64 data);

int kvm_msr_read(struct kvm_vcpu *vcpu, u32 index, u64 *data);

int kvm_msr_write(struct kvm_vcpu *vcpu, u32 index, u64 data);

int kvm_emulate_rdmsr(struct kvm_vcpu *vcpu);

int kvm_emulate_rdmsr_imm(struct kvm_vcpu *vcpu, u32 msr, int reg);

int kvm_emulate_wrmsr(struct kvm_vcpu *vcpu);

arch/x86/kvm/cpuid.c

+1 −1
Original line number Diff line number Diff line
@@ -2006,7 +2006,7 @@ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, 
		if (function == 7 && index == 0) {

			u64 data;

			if ((*ebx & (feature_bit(RTM) | feature_bit(HLE))) &&

			    !__kvm_get_msr(vcpu, MSR_IA32_TSX_CTRL, &data, true) &&

			    !kvm_msr_read(vcpu, MSR_IA32_TSX_CTRL, &data) &&

			    (data & TSX_CTRL_CPUID_CLEAR))

				*ebx &= ~(feature_bit(RTM) | feature_bit(HLE));

		} else if (function == 0x80000007) {

arch/x86/kvm/x86.c

+13 −3
Original line number Diff line number Diff line
@@ -1899,7 +1899,7 @@ static int kvm_set_msr_ignored_check(struct kvm_vcpu *vcpu, 
 * Returns 0 on success, non-0 otherwise.

 * Assumes vcpu_load() was already called.

 */

int __kvm_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data,

static int __kvm_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data,

			 bool host_initiated)

{

	struct msr_data msr;
@@ -1926,6 +1926,16 @@ int __kvm_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data, 
	return ret;

}



int kvm_msr_write(struct kvm_vcpu *vcpu, u32 index, u64 data)

{

	return __kvm_set_msr(vcpu, index, data, true);

}



int kvm_msr_read(struct kvm_vcpu *vcpu, u32 index, u64 *data)

{

	return __kvm_get_msr(vcpu, index, data, true);

}



static int kvm_get_msr_ignored_check(struct kvm_vcpu *vcpu,

				     u32 index, u64 *data, bool host_initiated)

{
@@ -12472,7 +12482,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) 
						  MSR_IA32_MISC_ENABLE_BTS_UNAVAIL;



		__kvm_set_xcr(vcpu, 0, XFEATURE_MASK_FP);

		__kvm_set_msr(vcpu, MSR_IA32_XSS, 0, true);

		kvm_msr_write(vcpu, MSR_IA32_XSS, 0);

	}



	/* All GPRs except RDX (handled below) are zeroed on RESET/INIT. */