x86/reboot: Disable virtualization in an emergency if SVM is supported

[linux-block.git] / arch / x86 / kernel / reboot.c

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 374c14b3a9bf901839f325c1eca13afe998f4cec..d03c551defccf03336a1276a97d7c79267cbb212 100644 (file)
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -530,27 +530,26 @@ static inline void kb_wait(void)
 
 static inline void nmi_shootdown_cpus_on_restart(void);
 
-/* Use NMIs as IPIs to tell all CPUs to disable virtualization */
-static void emergency_vmx_disable_all(void)
+static void emergency_reboot_disable_virtualization(void)
 {
        /* Just make sure we won't change CPUs while doing this */
        local_irq_disable();
 
        /*
-        * Disable VMX on all CPUs before rebooting, otherwise we risk hanging
-        * the machine, because the CPU blocks INIT when it's in VMX root.
+        * Disable virtualization on all CPUs before rebooting to avoid hanging
+        * the system, as VMX and SVM block INIT when running in the host.
         *
         * We can't take any locks and we may be on an inconsistent state, so
-        * use NMIs as IPIs to tell the other CPUs to exit VMX root and halt.
+        * use NMIs as IPIs to tell the other CPUs to disable VMX/SVM and halt.
         *
-        * Do the NMI shootdown even if VMX if off on _this_ CPU, as that
-        * doesn't prevent a different CPU from being in VMX root operation.
+        * Do the NMI shootdown even if virtualization is off on _this_ CPU, as
+        * other CPUs may have virtualization enabled.
         */
-       if (cpu_has_vmx()) {
-               /* Safely force _this_ CPU out of VMX root operation. */
-               __cpu_emergency_vmxoff();
+       if (cpu_has_vmx() || cpu_has_svm(NULL)) {
+               /* Safely force _this_ CPU out of VMX/SVM operation. */
+               cpu_emergency_disable_virtualization();
 
-               /* Halt and exit VMX root operation on the other CPUs. */
+               /* Disable VMX/SVM and halt on other CPUs. */
                nmi_shootdown_cpus_on_restart();
        }
 }
@@ -587,7 +586,7 @@ static void native_machine_emergency_restart(void)
        unsigned short mode;
 
        if (reboot_emergency)
-               emergency_vmx_disable_all();
+               emergency_reboot_disable_virtualization();
 
        tboot_shutdown(TB_SHUTDOWN_REBOOT);