linux-kernel - [PATCH v2 09/15] KVM: VMX: Check guest support for RDTSCP before processing MSR_TSC

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Message-Id: <20200923180409.32255-10-sean.j.christopherson@intel.com>
Date:   Wed, 23 Sep 2020 11:04:03 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <sean.j.christopherson@...el.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
Subject: [PATCH v2 09/15] KVM: VMX: Check guest support for RDTSCP before processing MSR_TSC_AUX

Check for RDTSCP support prior to checking if MSR_TSC_AUX is in the uret
MSRs array so that the array lookup and manipulation are back-to-back.
This paves the way toward adding a helper to wrap the lookup and
manipulation.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/vmx/vmx.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index ca41ee8fac5d..ed9ce25d3807 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1722,9 +1722,11 @@ static void setup_msrs(struct vcpu_vmx *vmx)
 	index = __vmx_find_uret_msr(vmx, MSR_EFER);
 	if (index >= 0 && update_transition_efer(vmx, index))
 		move_msr_up(vmx, index, nr_active_uret_msrs++);
-	index = __vmx_find_uret_msr(vmx, MSR_TSC_AUX);
-	if (index >= 0 && guest_cpuid_has(&vmx->vcpu, X86_FEATURE_RDTSCP))
-		move_msr_up(vmx, index, nr_active_uret_msrs++);
+	if (guest_cpuid_has(&vmx->vcpu, X86_FEATURE_RDTSCP)) {
+		index = __vmx_find_uret_msr(vmx, MSR_TSC_AUX);
+		if (index >= 0)
+			move_msr_up(vmx, index, nr_active_uret_msrs++);
+	}
 	index = __vmx_find_uret_msr(vmx, MSR_IA32_TSX_CTRL);
 	if (index >= 0)
 		move_msr_up(vmx, index, nr_active_uret_msrs++);
-- 
2.28.0