arch/x86/xen/multicalls.h

   1 #ifndef _XEN_MULTICALLS_H
   2 #define _XEN_MULTICALLS_H
   3
   4 #include <trace/events/xen.h>
   5
   6 #include "xen-ops.h"
   7
   8 /* Multicalls */
   9 struct multicall_space
  10 {
  11         struct multicall_entry *mc;
  12         void *args;
  13 };
  14
  15 /* Allocate room for a multicall and its args */
  16 struct multicall_space __xen_mc_entry(size_t args);
  17
  18 DECLARE_PER_CPU(unsigned long, xen_mc_irq_flags);
  19
  20 /* Call to start a batch of multiple __xen_mc_entry()s.  Must be
  21    paired with xen_mc_issue() */
  22 static inline void xen_mc_batch(void)
  23 {
  24         unsigned long flags;
  25
  26         /* need to disable interrupts until this entry is complete */
  27         local_irq_save(flags);
  28         trace_xen_mc_batch(paravirt_get_lazy_mode());
  29         __this_cpu_write(xen_mc_irq_flags, flags);
  30 }
  31
  32 static inline struct multicall_space xen_mc_entry(size_t args)
  33 {
  34         xen_mc_batch();
  35         return __xen_mc_entry(args);
  36 }
  37
  38 /* Flush all pending multicalls */
  39 void xen_mc_flush(void);
  40
  41 /* Issue a multicall if we're not in a lazy mode */
  42 static inline void xen_mc_issue(unsigned mode)
  43 {
  44         trace_xen_mc_issue(mode);
  45
  46         if ((paravirt_get_lazy_mode() & mode) == 0)
  47                 xen_mc_flush();
  48
  49         /* restore flags saved in xen_mc_batch */
  50         local_irq_restore(percpu_read(xen_mc_irq_flags));
  51 }
  52
  53 /* Set up a callback to be called when the current batch is flushed */
  54 void xen_mc_callback(void (*fn)(void *), void *data);
  55
  56 /*
  57  * Try to extend the arguments of the previous multicall command.  The
  58  * previous command's op must match.  If it does, then it attempts to
  59  * extend the argument space allocated to the multicall entry by
  60  * arg_size bytes.
  61  *
  62  * The returned multicall_space will return with mc pointing to the
  63  * command on success, or NULL on failure, and args pointing to the
  64  * newly allocated space.
  65  */
  66 struct multicall_space xen_mc_extend_args(unsigned long op, size_t arg_size);
  67
  68 #endif /* _XEN_MULTICALLS_H */