arch/x86/xen/multicalls.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _XEN_MULTICALLS_H
   3 #define _XEN_MULTICALLS_H
   4
   5 #include <trace/events/xen.h>
   6
   7 #include "xen-ops.h"
   8
   9 /* Multicalls */
  10 struct multicall_space
  11 {
  12         struct multicall_entry *mc;
  13         void *args;
  14 };
  15
  16 /* Allocate room for a multicall and its args */
  17 struct multicall_space __xen_mc_entry(size_t args);
  18
  19 DECLARE_PER_CPU(unsigned long, xen_mc_irq_flags);
  20
  21 /* Call to start a batch of multiple __xen_mc_entry()s.  Must be
  22    paired with xen_mc_issue() */
  23 static inline void xen_mc_batch(void)
  24 {
  25         unsigned long flags;
  26
  27         /* need to disable interrupts until this entry is complete */
  28         local_irq_save(flags);
  29         trace_xen_mc_batch(paravirt_get_lazy_mode());
  30         __this_cpu_write(xen_mc_irq_flags, flags);
  31 }
  32
  33 static inline struct multicall_space xen_mc_entry(size_t args)
  34 {
  35         xen_mc_batch();
  36         return __xen_mc_entry(args);
  37 }
  38
  39 /* Flush all pending multicalls */
  40 void xen_mc_flush(void);
  41
  42 /* Issue a multicall if we're not in a lazy mode */
  43 static inline void xen_mc_issue(unsigned mode)
  44 {
  45         trace_xen_mc_issue(mode);
  46
  47         if ((paravirt_get_lazy_mode() & mode) == 0)
  48                 xen_mc_flush();
  49
  50         /* restore flags saved in xen_mc_batch */
  51         local_irq_restore(this_cpu_read(xen_mc_irq_flags));
  52 }
  53
  54 /* Set up a callback to be called when the current batch is flushed */
  55 void xen_mc_callback(void (*fn)(void *), void *data);
  56
  57 /*
  58  * Try to extend the arguments of the previous multicall command.  The
  59  * previous command's op must match.  If it does, then it attempts to
  60  * extend the argument space allocated to the multicall entry by
  61  * arg_size bytes.
  62  *
  63  * The returned multicall_space will return with mc pointing to the
  64  * command on success, or NULL on failure, and args pointing to the
  65  * newly allocated space.
  66  */
  67 struct multicall_space xen_mc_extend_args(unsigned long op, size_t arg_size);
  68
  69 #endif /* _XEN_MULTICALLS_H */