linux-kernel - [PATCH v6 10/25] KVM: x86: Add kvm_msr

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Date:   Thu, 14 Sep 2023 02:33:10 -0400
From:   Yang Weijiang <weijiang.yang@...el.com>
To:     seanjc@...gle.com, pbonzini@...hat.com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     dave.hansen@...el.com, peterz@...radead.org, chao.gao@...el.com,
        rick.p.edgecombe@...el.com, weijiang.yang@...el.com,
        john.allen@....com
Subject: [PATCH v6 10/25] 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.

Suggested-by: Sean Christopherson <seanjc@...gle.com>
Signed-off-by: Yang Weijiang <weijiang.yang@...el.com>
---
 arch/x86/include/asm/kvm_host.h |  4 +++-
 arch/x86/kvm/cpuid.c            |  2 +-
 arch/x86/kvm/x86.c              | 16 +++++++++++++---
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1a4def36d5bb..0fc5e6312e93 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1956,7 +1956,9 @@ void kvm_prepare_emulation_failure_exit(struct kvm_vcpu *vcpu);
 
 void kvm_enable_efer_bits(u64);
 bool kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer);
-int __kvm_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data, bool host_initiated);
+
+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_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data);
 int kvm_set_msr(struct kvm_vcpu *vcpu, u32 index, u64 data);
 int kvm_emulate_rdmsr(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 7c3e4a550ca7..1f206caec559 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -1531,7 +1531,7 @@ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx,
 		*edx = entry->edx;
 		if (function == 7 && index == 0) {
 			u64 data;
-		        if (!__kvm_get_msr(vcpu, MSR_IA32_TSX_CTRL, &data, true) &&
+		        if (!kvm_msr_read(vcpu, MSR_IA32_TSX_CTRL, &data) &&
 			    (data & TSX_CTRL_CPUID_CLEAR))
 				*ebx &= ~(F(RTM) | F(HLE));
 		} else if (function == 0x80000007) {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6c9c81e82e65..e0b55c043dab 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1917,8 +1917,8 @@ 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,
-		  bool host_initiated)
+static int __kvm_get_msr(struct kvm_vcpu *vcpu, u32 index, u64 *data,
+			 bool host_initiated)
 {
 	struct msr_data msr;
 	int ret;
@@ -1944,6 +1944,16 @@ 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)
 {
@@ -12082,7 +12092,7 @@ 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. */
-- 
2.27.0