KVM: x86: Add memory barrier on vmcs field lookup

[pandora-kernel.git] / arch / x86 / kvm / vmx.c

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 346fac6..690120f 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -573,8 +573,18 @@ static const int max_vmcs_field = ARRAY_SIZE(vmcs_field_to_offset_table);
 
 static inline short vmcs_field_to_offset(unsigned long field)
 {
-       if (field >= max_vmcs_field || vmcs_field_to_offset_table[field] == 0)
+       if (field >= max_vmcs_field)
                return -1;
+
+       /*
+        * FIXME: Mitigation for CVE-2017-5753.  To be replaced with a
+        * generic mechanism.
+        */
+       asm("lfence");
+
+       if (vmcs_field_to_offset_table[field] == 0)
+               return -1;
+
        return vmcs_field_to_offset_table[field];
 }