[Xen-changelog] [xen master] VMX: fix PAT value seen by guest

[patchbot@xxxxxxx]

commit fce79f8ce91dc45f3a4d699ee67c49e6cbeb1197
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Apr 1 16:49:18 2014 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Apr 1 16:49:18 2014 +0200

    VMX: fix PAT value seen by guest
    
    The XSA-60 fixes introduced a window during which the guest PAT gets
    forced to all zeros. This shouldn't be visible to the guest. Therefore
    we need to intercept PAT MSR accesses during that time period.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Liu Jinsong <jinsong.liu@xxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmx.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 94f3db2..77ce167 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -1033,6 +1033,8 @@ static void vmx_handle_cd(struct vcpu *v, unsigned long 
value)
 
             vmx_get_guest_pat(v, pat);
             vmx_set_guest_pat(v, uc_pat);
+            vmx_enable_intercept_for_msr(v, MSR_IA32_CR_PAT,
+                                         MSR_TYPE_R | MSR_TYPE_W);
 
             wbinvd();               /* flush possibly polluted cache */
             hvm_asid_flush_vcpu(v); /* invalidate memory type cached in TLB */
@@ -1042,6 +1044,9 @@ static void vmx_handle_cd(struct vcpu *v, unsigned long 
value)
         {
             v->arch.hvm_vcpu.cache_mode = NORMAL_CACHE_MODE;
             vmx_set_guest_pat(v, *pat);
+            if ( !iommu_enabled || iommu_snoop )
+                vmx_disable_intercept_for_msr(v, MSR_IA32_CR_PAT,
+                                              MSR_TYPE_R | MSR_TYPE_W);
             hvm_asid_flush_vcpu(v); /* no need to flush cache */
         }
     }
--
generated by git-patchbot for /home/xen/git/xen.git#master

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