linux-kernel - [PATCH 3.16 34/99] kvm: vmx: Set IA32_TSC

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Message-ID: <lsq.1554212307.778562253@decadent.org.uk>
Date:   Tue, 02 Apr 2019 14:38:27 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "Marc Orr" <marcorr@...gle.com>,
        "Jim Mattson" <jmattson@...gle.com>,
        "Sean Christopherson" <sean.j.christopherson@...el.com>,
        "Liran Alon" <liran.alon@...cle.com>,
        "Peter Shier" <pshier@...gle.com>,
        "Paolo Bonzini" <pbonzini@...hat.com>
Subject: [PATCH 3.16 34/99] kvm: vmx: Set IA32_TSC_AUX for legacy mode guests

3.16.65-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Jim Mattson <jmattson@...gle.com>

commit 0023ef39dc35c773c436eaa46ca539a26b308b55 upstream.

RDTSCP is supported in legacy mode as well as long mode. The
IA32_TSC_AUX MSR should be set to the correct guest value before
entering any guest that supports RDTSCP.

Fixes: 4e47c7a6d714 ("KVM: VMX: Add instruction rdtscp support for guest")
Signed-off-by: Jim Mattson <jmattson@...gle.com>
Reviewed-by: Peter Shier <pshier@...gle.com>
Reviewed-by: Marc Orr <marcorr@...gle.com>
Reviewed-by: Liran Alon <liran.alon@...cle.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@...el.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
[bwh: Backported to 3.16:
 - Keep testing vmx->rdtscp_enabled instead of guest_cpuid_has()
 - Adjust filename]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 arch/x86/kvm/vmx.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2077,9 +2077,6 @@ static void setup_msrs(struct vcpu_vmx *
 		index = __find_msr_index(vmx, MSR_CSTAR);
 		if (index >= 0)
 			move_msr_up(vmx, index, save_nmsrs++);
-		index = __find_msr_index(vmx, MSR_TSC_AUX);
-		if (index >= 0 && vmx->rdtscp_enabled)
-			move_msr_up(vmx, index, save_nmsrs++);
 		/*
 		 * MSR_STAR is only needed on long mode guests, and only
 		 * if efer.sce is enabled.
@@ -2092,6 +2089,9 @@ static void setup_msrs(struct vcpu_vmx *
 	index = __find_msr_index(vmx, MSR_EFER);
 	if (index >= 0 && update_transition_efer(vmx, index))
 		move_msr_up(vmx, index, save_nmsrs++);
+	index = __find_msr_index(vmx, MSR_TSC_AUX);
+	if (index >= 0 && vmx->rdtscp_enabled)
+		move_msr_up(vmx, index, save_nmsrs++);
 
 	vmx->save_nmsrs = save_nmsrs;