From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Tim Chen <tim.c.chen@linux.intel.com>
Date: Fri, 20 Oct 2017 17:04:35 -0700
Subject: [PATCH] x86/kvm: Toggle IBRS on VM entry and exit
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

CVE-2017-5753
CVE-2017-5715

Restore guest IBRS on VM entry and set it to 1 on VM exit
back to kernel.

Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
(cherry picked from commit 3dc28210342f174270bcefac74ef5d0b52ffd846)
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---
 arch/x86/kvm/vmx.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 8df195bbb41d..57d538fc7c75 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -9101,6 +9101,11 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 		__write_pkru(vcpu->arch.pkru);
 
 	atomic_switch_perf_msrs(vmx);
+
+	if (boot_cpu_has(X86_FEATURE_SPEC_CTRL))
+		add_atomic_switch_msr(vmx, MSR_IA32_SPEC_CTRL,
+			vcpu->arch.spec_ctrl, FEATURE_ENABLE_IBRS);
+
 	debugctlmsr = get_debugctlmsr();
 
 	vmx_arm_hv_timer(vcpu);
-- 
2.14.2