[PATCH] KVM: VMX: Use cached vcpu_vmx pointer in MSR and segment helpers

[PATCH] KVM: VMX: Use cached vcpu_vmx pointer in MSR and segment helpers

[zhanghao]

From 3d30672f614d0472bf15ba9dd1efd085cddd5a93 Mon Sep 17 00:00:00 2001
From: Hao Zhang <zhanghao1@kylinos.cn>
Date: Mon, 29 Jun 2026 09:52:32 +0800

vmx_get_msr() and vmx_set_msr() already cache to_vmx(vcpu) in a local
'vmx' pointer, but a few cases still open-code to_vmx(vcpu).  Use the
cached pointer for consistency.

Likewise, cache to_vmx(vcpu) in vmx_get_segment_base() instead of
open-coding it in both the real-mode check and the VMCS read path.

No functional change intended.

Signed-off-by: Hao Zhang <zhanghao1@kylinos.cn>
---
 arch/x86/kvm/vmx/vmx.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 2325be57d3d7..b9ae10273f6f 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2147,7 +2147,7 @@ int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		    !guest_has_spec_ctrl_msr(vcpu))
 			return 1;
 
-		msr_info->data = to_vmx(vcpu)->spec_ctrl;
+		msr_info->data = vmx->spec_ctrl;
 		break;
 	case MSR_IA32_SYSENTER_CS:
 		msr_info->data = vmcs_read32(GUEST_SYSENTER_CS);
@@ -2179,7 +2179,7 @@ int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		if (!msr_info->host_initiated &&
 		    !guest_cpu_cap_has(vcpu, X86_FEATURE_SGX_LC))
 			return 1;
-		msr_info->data = to_vmx(vcpu)->msr_ia32_sgxlepubkeyhash
+		msr_info->data = vmx->msr_ia32_sgxlepubkeyhash
 			[msr_info->index - MSR_IA32_SGXLEPUBKEYHASH0];
 		break;
 	case KVM_FIRST_EMULATED_VMX_MSR ... KVM_LAST_EMULATED_VMX_MSR:
@@ -2392,7 +2392,7 @@ int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 
 		vmx_guest_debugctl_write(vcpu, data);
 
-		if (intel_pmu_lbr_is_enabled(vcpu) && !to_vmx(vcpu)->lbr_desc.event &&
+		if (intel_pmu_lbr_is_enabled(vcpu) && !vmx->lbr_desc.event &&
 		    (data & DEBUGCTLMSR_LBR))
 			intel_pmu_create_guest_lbr_event(vcpu);
 		return 0;
@@ -2471,7 +2471,7 @@ int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		break;
 	case MSR_IA32_MCG_EXT_CTL:
 		if ((!msr_info->host_initiated &&
-		     !(to_vmx(vcpu)->msr_ia32_feature_control &
+		     !(vmx->msr_ia32_feature_control &
 		       FEAT_CTL_LMCE_ENABLED)) ||
 		    (data & ~MCG_EXT_CTL_LMCE_EN))
 			return 1;
@@ -3666,13 +3666,14 @@ void vmx_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg)
 
 u64 vmx_get_segment_base(struct kvm_vcpu *vcpu, int seg)
 {
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	struct kvm_segment s;
 
-	if (to_vmx(vcpu)->rmode.vm86_active) {
+	if (vmx->rmode.vm86_active) {
 		vmx_get_segment(vcpu, &s, seg);
 		return s.base;
 	}
-	return vmx_read_guest_seg_base(to_vmx(vcpu), seg);
+	return vmx_read_guest_seg_base(vmx, seg);
 }
 
 static int __vmx_get_cpl(struct kvm_vcpu *vcpu, bool no_cache)

base-commit: dc59e4fea9d83f03bad6bddf3fa2e52491777482
-- 
2.15.0

Re: [PATCH] KVM: VMX: Use cached vcpu_vmx pointer in MSR and segment helpers

[Sean Christopherson]

On Mon, Jun 29, 2026, zhanghao wrote:
> >From 3d30672f614d0472bf15ba9dd1efd085cddd5a93 Mon Sep 17 00:00:00 2001
> From: Hao Zhang <zhanghao1@kylinos.cn>
> Date: Mon, 29 Jun 2026 09:52:32 +0800

This is mangled, the initial "From 3d30672f614d0472bf15ba9dd1efd085cddd5a93..."
and "Date: ..." shouldn't exist.  I fixed it up manually, but please check your
setup to make sure what you post can be applied by others.