[Xen-devel] [patch 17/34] Xen-pv_ops: add flush_tlb_others paravirt_op

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

This patch adds a pv_op for flush_tlb_others.  Some hypervisors, such
as Xen, have much more efficient ways to implement cross-cpu tlb
shootdown than IPI, so expose an appropriate operation to allow it to
be used.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>

---
 arch/i386/kernel/paravirt.c |    1 +
 arch/i386/kernel/smp.c      |   15 ++++++++-------
 include/asm-i386/paravirt.h |    8 ++++++++
 include/asm-i386/tlbflush.h |   19 +++++++++++++++++--
 4 files changed, 34 insertions(+), 9 deletions(-)

===================================================================
--- a/arch/i386/kernel/paravirt.c
+++ b/arch/i386/kernel/paravirt.c
@@ -584,6 +584,7 @@ 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,
 
===================================================================
--- a/arch/i386/kernel/smp.c
+++ b/arch/i386/kernel/smp.c
@@ -256,7 +256,6 @@ static struct mm_struct * flush_mm;
 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(s
                 
        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();
 }
===================================================================
--- a/include/asm-i386/paravirt.h
+++ b/include/asm-i386/paravirt.h
@@ -15,6 +15,7 @@
 
 #ifndef __ASSEMBLY__
 #include <linux/types.h>
+#include <linux/cpumask.h>
 
 struct thread_struct;
 struct Xgt_desc_struct;
@@ -121,6 +122,8 @@ struct paravirt_ops
        void (*flush_tlb_user)(void);
        void (*flush_tlb_kernel)(void);
        void (*flush_tlb_single)(u32 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);
 
@@ -652,6 +655,11 @@ static inline void arch_exit_mmap(struct
 #define __flush_tlb()          PVOP_VCALL0(flush_tlb_user)
 #define __flush_tlb_global()   PVOP_VCALL0(flush_tlb_kernel)
 #define __flush_tlb_single(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)
 {
===================================================================
--- a/include/asm-i386/tlbflush.h
+++ b/include/asm-i386/tlbflush.h
@@ -79,10 +79,14 @@
  *  - 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
 
@@ -110,7 +114,12 @@ static inline void flush_tlb_range(struc
                __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(struc
        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()

-- 


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