[Xen-changelog] [xen stable-4.7] VMX: PLATFORM_INFO MSR is r/o

[patchbot@xxxxxxx]

commit 6e36296c6c38fa735cb91650c443fb096ac0a79d
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Oct 24 16:49:44 2017 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Oct 24 16:49:44 2017 +0200

    VMX: PLATFORM_INFO MSR is r/o
    
    Therefore all write attempts should produce #GP, just like on real
    hardware.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Acked-by: Kevin Tian <kevin.tian@xxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmx.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index a924020..bd76e50 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2703,7 +2703,7 @@ static int vmx_msr_read_intercept(unsigned int msr, 
uint64_t *msr_content)
         break;
 
     case MSR_INTEL_PLATFORM_INFO:
-        if ( rdmsr_safe(MSR_INTEL_PLATFORM_INFO, *msr_content) )
+        if ( !boot_cpu_has(X86_FEATURE_MSR_PLATFORM_INFO) )
             goto gp_fault;
         *msr_content = 0;
         break;
@@ -2918,6 +2918,7 @@ static int vmx_msr_write_intercept(unsigned int msr, 
uint64_t msr_content)
             goto gp_fault;
         break;
     case IA32_FEATURE_CONTROL_MSR:
+    case MSR_INTEL_PLATFORM_INFO:
     case MSR_IA32_VMX_BASIC ... MSR_IA32_VMX_VMFUNC:
         /* None of these MSRs are writeable. */
         goto gp_fault;
@@ -2932,12 +2933,6 @@ static int vmx_msr_write_intercept(unsigned int msr, 
uint64_t msr_content)
             goto gp_fault;
         break;
 
-    case MSR_INTEL_PLATFORM_INFO:
-        if ( msr_content ||
-             rdmsr_safe(MSR_INTEL_PLATFORM_INFO, msr_content) )
-            goto gp_fault;
-        break;
-
     default:
         if ( passive_domain_do_wrmsr(msr, msr_content) )
             return X86EMUL_OKAY;
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.7

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