linux-kernel - [PATCH 3/4] KVM: VMX: Drop caching of KVM's desired sec exec controls for vmcs01

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Date:   Tue, 10 Aug 2021 10:19:51 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Zeng Guang <guang.zeng@...el.com>
Subject: [PATCH 3/4] KVM: VMX: Drop caching of KVM's desired sec exec controls
 for vmcs01

Remove the secondary execution controls cache now that it's effectively
dead code; it is only read immediately after it is written.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/vmx/vmx.c | 20 ++++++++------------
 arch/x86/kvm/vmx/vmx.h |  3 +--
 2 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index ae8e62df16dd..6c93122363b2 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -4212,7 +4212,7 @@ vmx_adjust_secondary_exec_control(struct vcpu_vmx *vmx, u32 *exec_control,
 #define vmx_adjust_sec_exec_exiting(vmx, exec_control, lname, uname) \
 	vmx_adjust_sec_exec_control(vmx, exec_control, lname, uname, uname##_EXITING, true)
 
-static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)
+u32 vmx_secondary_exec_control(struct vcpu_vmx *vmx)
 {
 	struct kvm_vcpu *vcpu = &vmx->vcpu;
 
@@ -4298,7 +4298,7 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)
 	if (!vcpu->kvm->arch.bus_lock_detection_enabled)
 		exec_control &= ~SECONDARY_EXEC_BUS_LOCK_DETECTION;
 
-	vmx->secondary_exec_control = exec_control;
+	return exec_control;
 }
 
 #define VMX_XSS_EXIT_BITMAP 0
@@ -4322,10 +4322,8 @@ static void init_vmcs(struct vcpu_vmx *vmx)
 
 	exec_controls_set(vmx, vmx_exec_control(vmx));
 
-	if (cpu_has_secondary_exec_ctrls()) {
-		vmx_compute_secondary_exec_control(vmx);
-		secondary_exec_controls_set(vmx, vmx->secondary_exec_control);
-	}
+	if (cpu_has_secondary_exec_ctrls())
+		secondary_exec_controls_set(vmx, vmx_secondary_exec_control(vmx));
 
 	if (kvm_vcpu_apicv_active(&vmx->vcpu)) {
 		vmcs_write64(EOI_EXIT_BITMAP0, 0);
@@ -6982,7 +6980,7 @@ static u64 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
 	return (cache << VMX_EPT_MT_EPTE_SHIFT) | ipat;
 }
 
-static void vmcs_set_secondary_exec_control(struct vcpu_vmx *vmx)
+static void vmcs_set_secondary_exec_control(struct vcpu_vmx *vmx, u32 new_ctl)
 {
 	/*
 	 * These bits in the secondary execution controls field
@@ -6996,7 +6994,6 @@ static void vmcs_set_secondary_exec_control(struct vcpu_vmx *vmx)
 		SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
 		SECONDARY_EXEC_DESC;
 
-	u32 new_ctl = vmx->secondary_exec_control;
 	u32 cur_ctl = secondary_exec_controls_get(vmx);
 
 	secondary_exec_controls_set(vmx, (new_ctl & ~mask) | (cur_ctl & mask));
@@ -7141,10 +7138,9 @@ static void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 
 	vmx_setup_uret_msrs(vmx);
 
-	if (cpu_has_secondary_exec_ctrls()) {
-		vmx_compute_secondary_exec_control(vmx);
-		vmcs_set_secondary_exec_control(vmx);
-	}
+	if (cpu_has_secondary_exec_ctrls())
+		vmcs_set_secondary_exec_control(vmx,
+						vmx_secondary_exec_control(vmx));
 
 	if (nested_vmx_allowed(vcpu))
 		to_vmx(vcpu)->msr_ia32_feature_control_valid_bits |=
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 414b440de9ac..2bd07867e9da 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -263,8 +263,6 @@ struct vcpu_vmx {
 	u64		      spec_ctrl;
 	u32		      msr_ia32_umwait_control;
 
-	u32 secondary_exec_control;
-
 	/*
 	 * loaded_vmcs points to the VMCS currently used in this vcpu. For a
 	 * non-nested (L1) guest, it always points to vmcs01. For a nested
@@ -477,6 +475,7 @@ static inline u32 vmx_vmexit_ctrl(void)
 }
 
 u32 vmx_exec_control(struct vcpu_vmx *vmx);
+u32 vmx_secondary_exec_control(struct vcpu_vmx *vmx);
 u32 vmx_pin_based_exec_ctrl(struct vcpu_vmx *vmx);
 
 static inline struct kvm_vmx *to_kvm_vmx(struct kvm *kvm)
-- 
2.32.0.605.g8dce9f2422-goog