1 files changed, 25 insertions, 61 deletions

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 268553817909..c689d19e35ab 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -26,37 +26,21 @@
 #include <linux/kdebug.h>
 #include <asm/smp.h>
 #include <asm/reboot.h>
+#include <asm/virtext.h>
 
 #include <mach_ipi.h>
 
-/* This keeps a track of which one is crashing cpu. */
-static int crashing_cpu;
 
 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
-static atomic_t waiting_for_crash_ipi;
 
-static int crash_nmi_callback(struct notifier_block *self,
-                        unsigned long val, void *data)
+static void kdump_nmi_callback(int cpu, struct die_args *args)
 {
         struct pt_regs *regs;
 #ifdef CONFIG_X86_32
         struct pt_regs fixed_regs;
 #endif
-        int cpu;
 
-        if (val != DIE_NMI_IPI)
-                return NOTIFY_OK;
-
-        regs = ((struct die_args *)data)->regs;
-        cpu = raw_smp_processor_id();
-
-        /* Don't do anything if this handler is invoked on crashing cpu.
-         * Otherwise, system will completely hang. Crashing cpu can get
-         * an NMI if system was initially booted with nmi_watchdog parameter.
-         */
-        if (cpu == crashing_cpu)
-                return NOTIFY_STOP;
-        local_irq_disable();
+        regs = args->regs;
 
 #ifdef CONFIG_X86_32
         if (!user_mode_vm(regs)) {
@@ -65,54 +49,28 @@ static int crash_nmi_callback(struct notifier_block *self,
         }
 #endif
         crash_save_cpu(regs, cpu);
-        disable_local_APIC();
-        atomic_dec(&waiting_for_crash_ipi);
-        /* Assume hlt works */
-        halt();
-        for (;;)
-                cpu_relax();
 
-        return 1;
-}
+        /* Disable VMX or SVM if needed.
+         *
+         * We need to disable virtualization on all CPUs.
+         * Having VMX or SVM enabled on any CPU may break rebooting
+         * after the kdump kernel has finished its task.
+         */
+        cpu_emergency_vmxoff();
+        cpu_emergency_svm_disable();
 
-static void smp_send_nmi_allbutself(void)
-{
-        cpumask_t mask = cpu_online_map;
-        cpu_clear(safe_smp_processor_id(), mask);
-        if (!cpus_empty(mask))
-                send_IPI_mask(mask, NMI_VECTOR);
+        disable_local_APIC();
 }
 
-static struct notifier_block crash_nmi_nb = {
-        .notifier_call = crash_nmi_callback,
-};
-
-static void nmi_shootdown_cpus(void)
+static void kdump_nmi_shootdown_cpus(void)
 {
-        unsigned long msecs;
-
-        atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
-        /* Would it be better to replace the trap vector here? */
-        if (register_die_notifier(&crash_nmi_nb))
-                return;         /* return what? */
-        /* Ensure the new callback function is set before sending
-         * out the NMI
-         */
-        wmb();
-
-        smp_send_nmi_allbutself();
-
-        msecs = 1000; /* Wait at most a second for the other cpus to stop */
-        while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
-                mdelay(1);
-                msecs--;
-        }
+        nmi_shootdown_cpus(kdump_nmi_callback);
 
-        /* Leave the nmi callback set */
         disable_local_APIC();
 }
+
 #else
-static void nmi_shootdown_cpus(void)
+static void kdump_nmi_shootdown_cpus(void)
 {
         /* There are no cpus to shootdown */
 }
@@ -131,9 +89,15 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
         /* The kernel is broken so disable interrupts */
         local_irq_disable();
 
-        /* Make a note of crashing cpu. Will be used in NMI callback.*/
-        crashing_cpu = safe_smp_processor_id();
-        nmi_shootdown_cpus();
+        kdump_nmi_shootdown_cpus();
+
+        /* Booting kdump kernel with VMX or SVM enabled won't work,
+         * because (among other limitations) we can't disable paging
+         * with the virt flags.
+         */
+        cpu_emergency_vmxoff();
+        cpu_emergency_svm_disable();
+
         lapic_shutdown();
 #if defined(CONFIG_X86_IO_APIC)
         disable_IO_APIC();