lguest: documentation update
[deliverable/linux.git] / include / asm-x86 / lguest_hcall.h
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1/* Architecture specific portion of the lguest hypercalls */
2#ifndef _X86_LGUEST_HCALL_H
3#define _X86_LGUEST_HCALL_H
4
5#define LHCALL_FLUSH_ASYNC 0
6#define LHCALL_LGUEST_INIT 1
7#define LHCALL_CRASH 2
8#define LHCALL_LOAD_GDT 3
9#define LHCALL_NEW_PGTABLE 4
10#define LHCALL_FLUSH_TLB 5
11#define LHCALL_LOAD_IDT_ENTRY 6
12#define LHCALL_SET_STACK 7
13#define LHCALL_TS 8
14#define LHCALL_SET_CLOCKEVENT 9
15#define LHCALL_HALT 10
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16#define LHCALL_SET_PTE 14
17#define LHCALL_SET_PMD 15
18#define LHCALL_LOAD_TLS 16
15045275 19#define LHCALL_NOTIFY 17
c37ae93d 20
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21#define LGUEST_TRAP_ENTRY 0x1F
22
23#ifndef __ASSEMBLY__
24#include <asm/hw_irq.h>
25
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26/*G:031 First, how does our Guest contact the Host to ask for privileged
27 * operations? There are two ways: the direct way is to make a "hypercall",
28 * to make requests of the Host Itself.
29 *
30 * Our hypercall mechanism uses the highest unused trap code (traps 32 and
e1e72965 31 * above are used by real hardware interrupts). Fifteen hypercalls are
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32 * available: the hypercall number is put in the %eax register, and the
33 * arguments (when required) are placed in %edx, %ebx and %ecx. If a return
34 * value makes sense, it's returned in %eax.
35 *
36 * Grossly invalid calls result in Sudden Death at the hands of the vengeful
37 * Host, rather than returning failure. This reflects Winston Churchill's
38 * definition of a gentleman: "someone who is only rude intentionally". */
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39static inline unsigned long
40hcall(unsigned long call,
41 unsigned long arg1, unsigned long arg2, unsigned long arg3)
42{
43 /* "int" is the Intel instruction to trigger a trap. */
44 asm volatile("int $" __stringify(LGUEST_TRAP_ENTRY)
e1e72965 45 /* The call in %eax (aka "a") might be overwritten */
c37ae93d 46 : "=a"(call)
e1e72965 47 /* The arguments are in %eax, %edx, %ebx & %ecx */
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48 : "a"(call), "d"(arg1), "b"(arg2), "c"(arg3)
49 /* "memory" means this might write somewhere in memory.
50 * This isn't true for all calls, but it's safe to tell
51 * gcc that it might happen so it doesn't get clever. */
52 : "memory");
53 return call;
54}
55/*:*/
56
57void async_hcall(unsigned long call,
58 unsigned long arg1, unsigned long arg2, unsigned long arg3);
59
60/* Can't use our min() macro here: needs to be a constant */
61#define LGUEST_IRQS (NR_IRQS < 32 ? NR_IRQS: 32)
62
63#define LHCALL_RING_SIZE 64
b410e7b1 64struct hcall_args
c37ae93d 65{
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66 /* These map directly onto eax, ebx, ecx, edx in struct lguest_regs */
67 unsigned long arg0, arg2, arg3, arg1;
c37ae93d 68};
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69
70#endif /* !__ASSEMBLY__ */
c37ae93d 71#endif /* _I386_LGUEST_HCALL_H */
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