x86: cpu_emergency_svm_disable() function

This function can be used by the reboot or kdump code to forcibly
disable SVM on the CPU.
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

arch/x86/include/asm/virtext.h

@@ -121,4 +121,12 @@ static inline void cpu_svm_disable(void)
 	wrmsrl(MSR_EFER, efer & ~MSR_EFER_SVME_MASK);
 }
 
+/** Makes sure SVM is disabled, if it is supported on the CPU
+ */
+static inline void cpu_emergency_svm_disable(void)
+{
+	if (cpu_has_svm(NULL))
+		cpu_svm_disable();
+}
+
 #endif /* _ASM_X86_VIRTEX_H */