[PATCH v3 1/5] KVM: SVM: Refactor svm_update_lbrv()

[Shivansh Dhiman <shivansh.dhiman@amd.com>]

Rewrite the enable_lbrv computation in svm_update_lbrv() as a series of
'if' statements, and use nested_vmcb12_has_lbrv() instead of open-coding
the nested LBRV check.

No functional change intended.

Suggested-by: Yosry Ahmed <yosry@kernel.org>
Signed-off-by: Shivansh Dhiman <shivansh.dhiman@amd.com>
---
Changelog:
v3:
 * New patch.
 * Refactor the enable_lbrv computation into 'if' statements (Yosry Ahmed).

---
 arch/x86/kvm/svm/nested.c |  2 +-
 arch/x86/kvm/svm/svm.c    | 10 +++++++---
 arch/x86/kvm/svm/svm.h    |  1 +
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index c1485c3e691c..d3df6b22bfef 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -736,7 +736,7 @@ static int nested_svm_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3,
 	return 0;
 }
 
-static bool nested_vmcb12_has_lbrv(struct kvm_vcpu *vcpu)
+bool nested_vmcb12_has_lbrv(struct kvm_vcpu *vcpu)
 {
 	return guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) &&
 		(to_svm(vcpu)->nested.ctl.misc_ctl2 & SVM_MISC2_ENABLE_V_LBR);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index ef69a51ab27f..cead8f99d856 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -880,9 +880,13 @@ void svm_update_lbrv(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 	bool current_enable_lbrv = svm->vmcb->control.misc_ctl2 & SVM_MISC2_ENABLE_V_LBR;
-	bool enable_lbrv = (svm->vmcb->save.dbgctl & DEBUGCTLMSR_LBR) ||
-			    (is_guest_mode(vcpu) && guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) &&
-			    (svm->nested.ctl.misc_ctl2 & SVM_MISC2_ENABLE_V_LBR));
+	bool enable_lbrv = false;
+
+	if (svm->vmcb->save.dbgctl & DEBUGCTLMSR_LBR)
+		enable_lbrv = true;
+
+	if (is_guest_mode(vcpu) && nested_vmcb12_has_lbrv(vcpu))
+		enable_lbrv = true;
 
 	if (enable_lbrv && !current_enable_lbrv)
 		__svm_enable_lbrv(vcpu);
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 716be21fba33..8d77c10cf4f6 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -899,6 +899,7 @@ void nested_copy_vmcb_control_to_cache(struct vcpu_svm *svm,
 void nested_copy_vmcb_save_to_cache(struct vcpu_svm *svm,
 				    struct vmcb_save_area *save);
 void nested_sync_control_from_vmcb02(struct vcpu_svm *svm);
+bool nested_vmcb12_has_lbrv(struct kvm_vcpu *vcpu);
 void svm_switch_vmcb(struct vcpu_svm *svm, struct kvm_vmcb_info *target_vmcb);
 
 
-- 
2.43.0