From: Jim Mattson <jmattson@google.com>
Date: Wed, 5 Dec 2018 23:29:01 +0000 (-0800)
Subject: kvm: vmx: Skip all SYSCALL MSRs in setup_msrs() when !EFER.SCE
X-Git-Tag: Ubuntu-5.4-5.4.0-11.14~3894^2~83
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=84c8c5b8f82f9939b1bcb3b5e25da2b5fc47ab50;p=mirror_ubuntu-focal-kernel.git

kvm: vmx: Skip all SYSCALL MSRs in setup_msrs() when !EFER.SCE

Like IA32_STAR, IA32_LSTAR and IA32_FMASK only need to contain guest
values on VM-entry when the guest is in long mode and EFER.SCE is set.

Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Marc Orr <marcorr@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 2084db097622..579f4c4144d2 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1375,19 +1375,19 @@ static void setup_msrs(struct vcpu_vmx *vmx)
 
 	save_nmsrs = 0;
 #ifdef CONFIG_X86_64
-	if (is_long_mode(&vmx->vcpu)) {
-		index = __find_msr_index(vmx, MSR_SYSCALL_MASK);
+	/*
+	 * The SYSCALL MSRs are only needed on long mode guests, and only
+	 * when EFER.SCE is set.
+	 */
+	if (is_long_mode(&vmx->vcpu) && (vmx->vcpu.arch.efer & EFER_SCE)) {
+		index = __find_msr_index(vmx, MSR_STAR);
 		if (index >= 0)
 			move_msr_up(vmx, index, save_nmsrs++);
 		index = __find_msr_index(vmx, MSR_LSTAR);
 		if (index >= 0)
 			move_msr_up(vmx, index, save_nmsrs++);
-		/*
-		 * MSR_STAR is only needed on long mode guests, and only
-		 * if efer.sce is enabled.
-		 */
-		index = __find_msr_index(vmx, MSR_STAR);
-		if ((index >= 0) && (vmx->vcpu.arch.efer & EFER_SCE))
+		index = __find_msr_index(vmx, MSR_SYSCALL_MASK);
+		if (index >= 0)
 			move_msr_up(vmx, index, save_nmsrs++);
 	}
 #endif