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Commit d4c10477 authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Andi Kleen
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[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: default avatarJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
parent 63f70270

arch/i386/kernel/paravirt.c

+1 −0
Original line number Diff line number Diff line
@@ -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,

arch/i386/kernel/smp.c

+7 −6
Original line number Diff line number Diff line
@@ -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 @@ fastcall void smp_invalidate_interrupt(struct pt_regs *regs) 
	put_cpu_no_resched();

}



static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,

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();

}

include/asm-i386/paravirt.h

+9 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 


#ifndef __ASSEMBLY__

#include <linux/types.h>

#include <linux/cpumask.h>



struct thread_struct;

struct Xgt_desc_struct;
@@ -165,6 +166,8 @@ struct paravirt_ops 
	void (*flush_tlb_user)(void);

	void (*flush_tlb_kernel)(void);

	void (*flush_tlb_single)(unsigned long addr);

	void (*flush_tlb_others)(const cpumask_t *cpus, struct mm_struct *mm,

				 unsigned long va);



	void (*map_pt_hook)(int type, pte_t *va, u32 pfn);
@@ -853,6 +856,12 @@ static inline void __flush_tlb_single(unsigned long addr) 
	PVOP_VCALL1(flush_tlb_single, addr);

}



static inline void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,

				    unsigned long va)

{

	PVOP_VCALL3(flush_tlb_others, &cpumask, mm, va);

}



static inline void paravirt_map_pt_hook(int type, pte_t *va, u32 pfn)

{

	PVOP_VCALL3(map_pt_hook, type, va, pfn);

include/asm-i386/tlbflush.h

+17 −2
Original line number Diff line number Diff line
@@ -79,11 +79,15 @@ 
 *  - flush_tlb_range(vma, start, end) flushes a range of pages

 *  - flush_tlb_kernel_range(start, end) flushes a range of kernel pages

 *  - flush_tlb_pgtables(mm, start, end) flushes a range of page tables

 *  - flush_tlb_others(cpumask, mm, va) flushes a TLBs on other cpus

 *

 * ..but the i386 has somewhat limited tlb flushing capabilities,

 * and page-granular flushes are available only on i486 and up.

 */



#define TLB_FLUSH_ALL	0xffffffff





#ifndef CONFIG_SMP



#define flush_tlb() __flush_tlb()
@@ -110,7 +114,12 @@ static inline void flush_tlb_range(struct vm_area_struct *vma, 
		__flush_tlb();

}



#else

static inline void native_flush_tlb_others(const cpumask_t *cpumask,

					   struct mm_struct *mm, unsigned long va)

{

}



#else  /* SMP */



#include <asm/smp.h>
@@ -129,6 +138,9 @@ static inline void flush_tlb_range(struct vm_area_struct * vma, unsigned long st 
	flush_tlb_mm(vma->vm_mm);

}



void native_flush_tlb_others(const cpumask_t *cpumask, struct mm_struct *mm,

			     unsigned long va);



#define TLBSTATE_OK	1

#define TLBSTATE_LAZY	2
@@ -139,8 +151,11 @@ struct tlb_state 
	char __cacheline_padding[L1_CACHE_BYTES-8];

};

DECLARE_PER_CPU(struct tlb_state, cpu_tlbstate);

#endif	/* SMP */





#ifndef CONFIG_PARAVIRT

#define flush_tlb_others(mask, mm, va)		\

	native_flush_tlb_others(&mask, mm, va)

#endif



#define flush_tlb_kernel_range(start, end) flush_tlb_all()