Merge branch 'x86-xen-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-xen-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (42 commits)
  xen: cache cr0 value to avoid trap'n'emulate for read_cr0
  xen/x86-64: clean up warnings about IST-using traps
  xen/x86-64: fix breakpoints and hardware watchpoints
  xen: reserve Xen start_info rather than e820 reserving
  xen: add FIX_TEXT_POKE to fixmap
  lguest: update lazy mmu changes to match lguest's use of kvm hypercalls
  xen: honour VCPU availability on boot
  xen: add "capabilities" file
  xen: drop kexec bits from /sys/hypervisor since kexec isn't implemented yet
  xen/sys/hypervisor: change writable_pt to features
  xen: add /sys/hypervisor support
  xen/xenbus: export xenbus_dev_changed
  xen: use device model for suspending xenbus devices
  xen: remove suspend_cancel hook
  xen/dev-evtchn: clean up locking in evtchn
  xen: export ioctl headers to userspace
  xen: add /dev/xen/evtchn driver
  xen: add irq_from_evtchn
  xen: clean up gate trap/interrupt constants
  xen: set _PAGE_NX in __supported_pte_mask before pagetable construction
  ...

1 files changed, 26 insertions, 30 deletions

diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 9faf43bea336..70ec9b951d76 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -248,18 +248,16 @@ static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LA
 
 static inline void enter_lazy(enum paravirt_lazy_mode mode)
 {
-        BUG_ON(__get_cpu_var(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);
-        BUG_ON(preemptible());
+        BUG_ON(percpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);
 
-        __get_cpu_var(paravirt_lazy_mode) = mode;
+        percpu_write(paravirt_lazy_mode, mode);
 }
 
-void paravirt_leave_lazy(enum paravirt_lazy_mode mode)
+static void leave_lazy(enum paravirt_lazy_mode mode)
 {
-        BUG_ON(__get_cpu_var(paravirt_lazy_mode) != mode);
-        BUG_ON(preemptible());
+        BUG_ON(percpu_read(paravirt_lazy_mode) != mode);
 
-        __get_cpu_var(paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;
+        percpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE);
 }
 
 void paravirt_enter_lazy_mmu(void)
@@ -269,22 +267,36 @@ void paravirt_enter_lazy_mmu(void)
 
 void paravirt_leave_lazy_mmu(void)
 {
-        paravirt_leave_lazy(PARAVIRT_LAZY_MMU);
+        leave_lazy(PARAVIRT_LAZY_MMU);
 }
 
-void paravirt_enter_lazy_cpu(void)
+void paravirt_start_context_switch(struct task_struct *prev)
 {
+        BUG_ON(preemptible());
+
+        if (percpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
+                arch_leave_lazy_mmu_mode();
+                set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
+        }
         enter_lazy(PARAVIRT_LAZY_CPU);
 }
 
-void paravirt_leave_lazy_cpu(void)
+void paravirt_end_context_switch(struct task_struct *next)
 {
-        paravirt_leave_lazy(PARAVIRT_LAZY_CPU);
+        BUG_ON(preemptible());
+
+        leave_lazy(PARAVIRT_LAZY_CPU);
+
+        if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
+                arch_enter_lazy_mmu_mode();
 }
 
 enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
 {
-        return __get_cpu_var(paravirt_lazy_mode);
+        if (in_interrupt())
+                return PARAVIRT_LAZY_NONE;
+
+        return percpu_read(paravirt_lazy_mode);
 }
 
 void arch_flush_lazy_mmu_mode(void)
@@ -292,7 +304,6 @@ void arch_flush_lazy_mmu_mode(void)
         preempt_disable();
 
         if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
-                WARN_ON(preempt_count() == 1);
                 arch_leave_lazy_mmu_mode();
                 arch_enter_lazy_mmu_mode();
         }
@@ -300,19 +311,6 @@ void arch_flush_lazy_mmu_mode(void)
         preempt_enable();
 }
 
-void arch_flush_lazy_cpu_mode(void)
-{
-        preempt_disable();
-
-        if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
-                WARN_ON(preempt_count() == 1);
-                arch_leave_lazy_cpu_mode();
-                arch_enter_lazy_cpu_mode();
-        }
-
-        preempt_enable();
-}
-
 struct pv_info pv_info = {
         .name = "bare hardware",
         .paravirt_enabled = 0,
@@ -404,10 +402,8 @@ struct pv_cpu_ops pv_cpu_ops = {
         .set_iopl_mask = native_set_iopl_mask,
         .io_delay = native_io_delay,
 
-        .lazy_mode = {
-                .enter = paravirt_nop,
-                .leave = paravirt_nop,
-        },
+        .start_context_switch = paravirt_nop,
+        .end_context_switch = paravirt_nop,
 };
 
 struct pv_apic_ops pv_apic_ops = {