linux-kernel - [PATCH v3 25/25] KVM: nVMX: Use cached host MSR_IA32_VMX

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Message-Id: <20220708144223.610080-26-vkuznets@redhat.com>
Date:   Fri,  8 Jul 2022 16:42:23 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     kvm@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>
Cc:     Anirudh Rayabharam <anrayabh@...ux.microsoft.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Maxim Levitsky <mlevitsk@...hat.com>,
        linux-hyperv@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v3 25/25] KVM: nVMX: Use cached host MSR_IA32_VMX_MISC value for setting up nested MSR

vmcs_config has cased host MSR_IA32_VMX_MISC value, use it for setting
up nested MSR_IA32_VMX_MISC in nested_vmx_setup_ctls_msrs() and avoid the
redundant rdmsr().

No (real) functional change intended.

Reviewed-by: Jim Mattson <jmattson@...gle.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
---
 arch/x86/kvm/vmx/nested.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 3d386c663fac..8026dab71086 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -6754,10 +6754,7 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)
 		msrs->secondary_ctls_high |= SECONDARY_EXEC_ENCLS_EXITING;
 
 	/* miscellaneous data */
-	rdmsr(MSR_IA32_VMX_MISC,
-		msrs->misc_low,
-		msrs->misc_high);
-	msrs->misc_low &= VMX_MISC_SAVE_EFER_LMA;
+	msrs->misc_low = (u32)vmcs_conf->misc & VMX_MISC_SAVE_EFER_LMA;
 	msrs->misc_low |=
 		MSR_IA32_VMX_MISC_VMWRITE_SHADOW_RO_FIELDS |
 		VMX_MISC_EMULATED_PREEMPTION_TIMER_RATE |
-- 
2.35.3