[PATCH] x86: implement flush_tlb_all in terms of flush_tlb_others

[Jeremy Fitzhardinge]

Modify flush_tlb_others to take a NULL mm, meaning "flush user
and kernel tlbs", and implement flush_tlb_all in terms of that.

The principle motivation for this is to make sure it goes via
paravirt_ops, which allows for more efficient cross-cpu tlb
flushes than a plain IPI.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 14c5af4..2d112f9 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -148,7 +148,13 @@ void smp_invalidate_interrupt(struct pt_regs *regs)
 		 * BUG();
 		 */
 
-	if (f->flush_mm == percpu_read(cpu_tlbstate.active_mm)) {
+	if (f->flush_mm == NULL) {
+		/* No mm - flush all kernel and user tlbs */
+		__flush_tlb_all();
+		if (percpu_read(cpu_tlbstate.state) == TLBSTATE_LAZY)
+			leave_mm(cpu);
+	} else if (f->flush_mm == percpu_read(cpu_tlbstate.active_mm)) {
+		/* Flushing a specific user mm */
 		if (percpu_read(cpu_tlbstate.state) == TLBSTATE_OK) {
 			if (f->flush_va == TLB_FLUSH_ALL)
 				local_flush_tlb();
@@ -281,16 +287,15 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long va)
 	preempt_enable();
 }
 
-static void do_flush_tlb_all(void *info)
+void flush_tlb_all(void)
 {
-	unsigned long cpu = smp_processor_id();
+	preempt_disable();
+
+	flush_tlb_others(cpu_online_mask, NULL, TLB_FLUSH_ALL);
 
 	__flush_tlb_all();
 	if (percpu_read(cpu_tlbstate.state) == TLBSTATE_LAZY)
-		leave_mm(cpu);
-}
+		leave_mm(smp_processor_id());
 
-void flush_tlb_all(void)
-{
-	on_each_cpu(do_flush_tlb_all, NULL, 1);
+	preempt_enable();
 }
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 7cadab1..dc83b47 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1350,7 +1350,6 @@ static void xen_flush_tlb_others(const struct cpumask *cpus,
 	struct multicall_space mcs;
 
 	BUG_ON(cpumask_empty(cpus));
-	BUG_ON(!mm);
 
 	mcs = xen_mc_entry(sizeof(*args));
 	args = mcs.args;


    J
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