[PATCH] i386: PARAVIRT: add flush_tlb_others paravirt_op

This patch adds a pv_op for flush_tlb_others.  Linux running on native
hardware uses cross-CPU IPIs to flush the TLB on any CPU which may
have a particular mm's pagetable entries cached in its TLB.  This is
inefficient in a paravirtualized environment, since the hypervisor
knows which real CPUs actually contain cached mappings, which may be a
small subset of a guest's VCPUs.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>

2 files changed, 8 insertions, 6 deletions

diff --git a/arch/i386/kernel/paravirt.c b/arch/i386/kernel/paravirt.c
index b0ed163e6f70..c7f0cf92925f 100644
--- a/arch/i386/kernel/paravirt.c
+++ b/arch/i386/kernel/paravirt.c
@@ -300,6 +300,7 @@ struct paravirt_ops paravirt_ops = {
         .flush_tlb_user = native_flush_tlb,
         .flush_tlb_kernel = native_flush_tlb_global,
         .flush_tlb_single = native_flush_tlb_single,
+        .flush_tlb_others = native_flush_tlb_others,
 
         .map_pt_hook = paravirt_nop,
 
diff --git a/arch/i386/kernel/smp.c b/arch/i386/kernel/smp.c
index 9d84f6f001bf..892cd64130bc 100644
--- a/arch/i386/kernel/smp.c
+++ b/arch/i386/kernel/smp.c
@@ -256,7 +256,6 @@ static cpumask_t flush_cpumask;
 static struct mm_struct * flush_mm;
 static unsigned long flush_va;
 static DEFINE_SPINLOCK(tlbstate_lock);
-#define FLUSH_ALL       0xffffffff
 
 /*
  * We cannot call mmdrop() because we are in interrupt context, 
@@ -338,7 +337,7 @@ fastcall void smp_invalidate_interrupt(struct pt_regs *regs)
                  
         if (flush_mm == per_cpu(cpu_tlbstate, cpu).active_mm) {
                 if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK) {
-                        if (flush_va == FLUSH_ALL)
+                        if (flush_va == TLB_FLUSH_ALL)
                                 local_flush_tlb();
                         else
                                 __flush_tlb_one(flush_va);
@@ -353,9 +352,11 @@ out:
         put_cpu_no_resched();
 }
 
-static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
-                                                unsigned long va)
+void native_flush_tlb_others(const cpumask_t *cpumaskp, struct mm_struct *mm,
+                             unsigned long va)
 {
+        cpumask_t cpumask = *cpumaskp;
+
         /*
          * A couple of (to be removed) sanity checks:
          *
@@ -417,7 +418,7 @@ void flush_tlb_current_task(void)
 
         local_flush_tlb();
         if (!cpus_empty(cpu_mask))
-                flush_tlb_others(cpu_mask, mm, FLUSH_ALL);
+                flush_tlb_others(cpu_mask, mm, TLB_FLUSH_ALL);
         preempt_enable();
 }
 
@@ -436,7 +437,7 @@ void flush_tlb_mm (struct mm_struct * mm)
                         leave_mm(smp_processor_id());
         }
         if (!cpus_empty(cpu_mask))
-                flush_tlb_others(cpu_mask, mm, FLUSH_ALL);
+                flush_tlb_others(cpu_mask, mm, TLB_FLUSH_ALL);
 
         preempt_enable();
 }