x86: disable IOMMUs on kernel crash

If the IOMMUs are still enabled when the kexec kernel boots access to
the disk is not possible. This is bad for tools like kdump or anything
else which wants to use PCI devices.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

arch/x86/kernel/crash.c

@@ -27,6 +27,7 @@
 #include <asm/cpu.h>
 #include <asm/reboot.h>
 #include <asm/virtext.h>
+#include <asm/iommu.h>
 
 
 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
@@ -103,5 +104,10 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
 #ifdef CONFIG_HPET_TIMER
 	hpet_disable();
 #endif
+
+#ifdef CONFIG_X86_64
+	pci_iommu_shutdown();
+#endif
+
 	crash_save_cpu(regs, safe_smp_processor_id());
 }