x86/HVM: correct the SMEP logic for HVM_CR0_GUEST_RESERVED_BITS

When checking the SMEP feature for HVM guests, we should check the
VCPU instead of the host CPU.

Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index 31043b26bed7d73b5844d4b4cb01c00aa022497e..c373930c7c5a02e3c4513a213200187138eb39e1 100644 (file)
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -354,6 +354,19 @@ static inline int hvm_event_pending(struct vcpu *v)
     return hvm_funcs.event_pending(v);
 }
 
+static inline bool_t hvm_vcpu_has_smep(void)
+{
+    unsigned int eax, ebx;
+
+    hvm_cpuid(0, &eax, NULL, NULL, NULL);
+
+    if (eax < 7)
+        return 0;
+
+    hvm_cpuid(7, NULL, &ebx, NULL, NULL);
+    return !!(ebx & cpufeat_mask(X86_FEATURE_SMEP));
+}
+
 /* These reserved bits in lower 32 remain 0 after any load of CR0 */
 #define HVM_CR0_GUEST_RESERVED_BITS             \
     (~((unsigned long)                          \
@@ -373,7 +386,7 @@ static inline int hvm_event_pending(struct vcpu *v)
         X86_CR4_DE  | X86_CR4_PSE | X86_CR4_PAE |       \
         X86_CR4_MCE | X86_CR4_PGE | X86_CR4_PCE |       \
         X86_CR4_OSFXSR | X86_CR4_OSXMMEXCPT |           \
-        (cpu_has_smep ? X86_CR4_SMEP : 0) |             \
+        (hvm_vcpu_has_smep() ? X86_CR4_SMEP : 0) |      \
         (cpu_has_fsgsbase ? X86_CR4_FSGSBASE : 0) |     \
         ((nestedhvm_enabled((_v)->domain) && cpu_has_vmx)\
                       ? X86_CR4_VMXE : 0)  |             \