[PATCH v9 11/27] KVM: x86: Add kvm_msr_{read,write}() helpers

Yang Weijiang
2024-01-24T02:42:40Z

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: Sean Christopherson <seanjc@google.com>
Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
---
arch/x86/include/asm/kvm_host.h | 3 ++-
arch/x86/kvm/cpuid.c | 2 +-
arch/x86/kvm/x86.c | 16 +++++++++++++---
3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 5c665165024c..40dd796ea085 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -2012,9 +2012,10 @@ 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_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_wrmsr(struct kvm_vcpu *vcpu);
int kvm_emulate_as_nop(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 624954203b40..acc360c76318 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -1548,7 +1548,7 @@ 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 3671f4868d1b..594c9e025f95 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1920,8 +1920,8 @@ 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;
@@ -1947,6 +1947,16 @@ 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)
{
@@ -12296,7 +12306,7 @@ 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. */
--
2.39.3