From: Jan Beulich <jbeulich@suse.com>
Date: Fri, 3 Jun 2016 13:28:10 +0000 (+0200)
Subject: VMX: relax incoming BNDCFGS check
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~1026
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=268ead59ce10967cf7490353d743ebc1bb7a9a4c;p=xen.git

VMX: relax incoming BNDCFGS check

Accepting zero here even when !cpu_has_mpx makes the restore side
symmetric to the save logic (which avoids saving the value if zero),
i.e. makes either side independent of the logic on the other side.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>
---

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 3acf1ab98a..743b5a1442 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -824,7 +824,7 @@ static int vmx_load_msr(struct vcpu *v, struct hvm_msr *ctxt)
         case MSR_IA32_BNDCFGS:
             if ( cpu_has_mpx )
                 __vmwrite(GUEST_BNDCFGS, ctxt->msr[i].val);
-            else
+            else if ( ctxt->msr[i].val )
                 err = -ENXIO;
             break;
         case MSR_IA32_XSS: