[PATCH] x86: PARAVIRT: add hooks to intercept mm creation and destruction

Add hooks to allow a paravirt implementation to track the lifetime of
an mm.  Paravirtualization requires three hooks, but only two are
needed in common code.  They are:

arch_dup_mmap, which is called when a new mmap is created at fork

arch_exit_mmap, which is called when the last process reference to an
  mm is dropped, which typically happens on exit and exec.

The third hook is activate_mm, which is called from the arch-specific
activate_mm() macro/function, and so doesn't need stub versions for
other architectures.  It's called when an mm is first used.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: linux-arch@vger.kernel.org
Cc: James Bottomley <James.Bottomley@SteelEye.com>
Acked-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 23 insertions, 0 deletions

diff --git a/include/asm-i386/paravirt.h b/include/asm-i386/paravirt.h
index f93599dc7756..61c03f1e0c29 100644
--- a/include/asm-i386/paravirt.h
+++ b/include/asm-i386/paravirt.h
@@ -119,6 +119,12 @@ struct paravirt_ops
 
         void (*io_delay)(void);
 
+        void (*activate_mm)(struct mm_struct *prev,
+                            struct mm_struct *next);
+        void (*dup_mmap)(struct mm_struct *oldmm,
+                         struct mm_struct *mm);
+        void (*exit_mmap)(struct mm_struct *mm);
+
 #ifdef CONFIG_X86_LOCAL_APIC
         void (*apic_write)(unsigned long reg, unsigned long v);
         void (*apic_write_atomic)(unsigned long reg, unsigned long v);
@@ -395,6 +401,23 @@ static inline void startup_ipi_hook(int phys_apicid, unsigned long start_eip,
 }
 #endif
 
+static inline void paravirt_activate_mm(struct mm_struct *prev,
+                                        struct mm_struct *next)
+{
+        paravirt_ops.activate_mm(prev, next);
+}
+
+static inline void arch_dup_mmap(struct mm_struct *oldmm,
+                                 struct mm_struct *mm)
+{
+        paravirt_ops.dup_mmap(oldmm, mm);
+}
+
+static inline void arch_exit_mmap(struct mm_struct *mm)
+{
+        paravirt_ops.exit_mmap(mm);
+}
+
 #define __flush_tlb() paravirt_ops.flush_tlb_user()
 #define __flush_tlb_global() paravirt_ops.flush_tlb_kernel()
 #define __flush_tlb_single(addr) paravirt_ops.flush_tlb_single(addr)