From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Date: Thu, 11 Jan 2018 22:34:33 +0000 (-0500)
Subject: x86/spec: Always set IBRS to guest value on VMENTER and host on VMEXIT (redux)
X-Git-Tag: v4.1.12-124.31.3~1275
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=edf4b33e9f50537598637ab35598536343394947;p=users%2Fjedix%2Flinux-maple.git

x86/spec: Always set IBRS to guest value on VMENTER and host on VMEXIT (redux)

The commit bc5d49f8ee73ddf252f8a4ed106643abed3bb4d6
that was pulled was a bit stale and missing an important change.

We will set the IBRS to 0 unconditionally on VMENTER.

Orabug: 27378451

Reported-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Brian Maly <brian.maly@oracle.com>
Signed-off-by: Kirtikar Kashyap <kirtikar.kashyap@oracle.com>
---

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 0ce64443f9ef5..3d6da9efdda79 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8192,8 +8192,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 
 	vmx->__launched = vmx->loaded_vmcs->launched;
 
-	if (ibrs_inuse &&
-	    vmx->spec_ctrl != SPEC_CTRL_FEATURE_ENABLE_IBRS)
+	if (ibrs_inuse)
 		wrmsrl(MSR_IA32_SPEC_CTRL, vmx->spec_ctrl);
 
 	asm(