1 files changed, 30 insertions, 12 deletions

diff --git a/arch/i386/kernel/apm.c b/arch/i386/kernel/apm.c
index b42f2d914af3..a97847da9ed5 100644
--- a/arch/i386/kernel/apm.c
+++ b/arch/i386/kernel/apm.c
@@ -198,7 +198,7 @@
  *   (APM) BIOS Interface Specification, Revision 1.2, February 1996.
  *
  * [This document is available from Microsoft at:
- *    http://www.microsoft.com/hwdev/busbios/amp_12.htm]
+ *    http://www.microsoft.com/whdc/archive/amp_12.mspx]
  */
 
 #include <linux/module.h>
@@ -231,6 +231,7 @@
 #include <asm/uaccess.h>
 #include <asm/desc.h>
 #include <asm/i8253.h>
+#include <asm/paravirt.h>
 
 #include "io_ports.h"
 
@@ -540,11 +541,30 @@ static inline void apm_restore_cpus(cpumask_t mask)
  * Also, we KNOW that for the non error case of apm_bios_call, there
  * is no useful data returned in the low order 8 bits of eax.
  */
-#define APM_DO_CLI      \
-        if (apm_info.allow_ints) \
-                local_irq_enable(); \
-        else \
+
+static inline unsigned long __apm_irq_save(void)
+{
+        unsigned long flags;
+        local_save_flags(flags);
+        if (apm_info.allow_ints) {
+                if (irqs_disabled_flags(flags))
+                        local_irq_enable();
+        } else
+                local_irq_disable();
+
+        return flags;
+}
+
+#define apm_irq_save(flags) \
+        do { flags = __apm_irq_save(); } while (0)
+
+static inline void apm_irq_restore(unsigned long flags)
+{
+        if (irqs_disabled_flags(flags))
                 local_irq_disable();
+        else if (irqs_disabled())
+                local_irq_enable();
+}
 
 #ifdef APM_ZERO_SEGS
 #       define APM_DECL_SEGS \
@@ -596,12 +616,11 @@ static u8 apm_bios_call(u32 func, u32 ebx_in, u32 ecx_in,
         save_desc_40 = gdt[0x40 / 8];
         gdt[0x40 / 8] = bad_bios_desc;
 
-        local_save_flags(flags);
-        APM_DO_CLI;
+        apm_irq_save(flags);
         APM_DO_SAVE_SEGS;
         apm_bios_call_asm(func, ebx_in, ecx_in, eax, ebx, ecx, edx, esi);
         APM_DO_RESTORE_SEGS;
-        local_irq_restore(flags);
+        apm_irq_restore(flags);
         gdt[0x40 / 8] = save_desc_40;
         put_cpu();
         apm_restore_cpus(cpus);
@@ -640,12 +659,11 @@ static u8 apm_bios_call_simple(u32 func, u32 ebx_in, u32 ecx_in, u32 *eax)
         save_desc_40 = gdt[0x40 / 8];
         gdt[0x40 / 8] = bad_bios_desc;
 
-        local_save_flags(flags);
-        APM_DO_CLI;
+        apm_irq_save(flags);
         APM_DO_SAVE_SEGS;
         error = apm_bios_call_simple_asm(func, ebx_in, ecx_in, eax);
         APM_DO_RESTORE_SEGS;
-        local_irq_restore(flags);
+        apm_irq_restore(flags);
         gdt[0x40 / 8] = save_desc_40;
         put_cpu();
         apm_restore_cpus(cpus);
@@ -2218,7 +2236,7 @@ static int __init apm_init(void)
 
         dmi_check_system(apm_dmi_table);
 
-        if (apm_info.bios.version == 0) {
+        if (apm_info.bios.version == 0 || paravirt_enabled()) {
                 printk(KERN_INFO "apm: BIOS not found.\n");
                 return -ENODEV;
         }