xref: /openbmc/linux/arch/x86/xen/multicalls.h (revision f3539c12)
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(this_cpu_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 */
69