vmm_instruction_emul.h revision 259128 
1/*-
2 * Copyright (c) 2012 NetApp, Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: releng/10.0/sys/amd64/include/vmm_instruction_emul.h 259128 2013-12-09 13:44:07Z gjb $
27 */
28
29#ifndef	_VMM_INSTRUCTION_EMUL_H_
30#define	_VMM_INSTRUCTION_EMUL_H_
31
32/*
33 * The data structures 'vie' and 'vie_op' are meant to be opaque to the
34 * consumers of instruction decoding. The only reason why their contents
35 * need to be exposed is because they are part of the 'vm_exit' structure.
36 */
37struct vie_op {
38	uint8_t		op_byte;	/* actual opcode byte */
39	uint8_t		op_type;	/* type of operation (e.g. MOV) */
40	uint16_t	op_flags;
41};
42
43#define	VIE_INST_SIZE	15
44struct vie {
45	uint8_t		inst[VIE_INST_SIZE];	/* instruction bytes */
46	uint8_t		num_valid;		/* size of the instruction */
47	uint8_t		num_processed;
48
49	uint8_t		rex_w:1,		/* REX prefix */
50			rex_r:1,
51			rex_x:1,
52			rex_b:1,
53			rex_present:1;
54
55	uint8_t		mod:2,			/* ModRM byte */
56			reg:4,
57			rm:4;
58
59	uint8_t		ss:2,			/* SIB byte */
60			index:4,
61			base:4;
62
63	uint8_t		disp_bytes;
64	uint8_t		imm_bytes;
65
66	uint8_t		scale;
67	int		base_register;		/* VM_REG_GUEST_xyz */
68	int		index_register;		/* VM_REG_GUEST_xyz */
69
70	int64_t		displacement;		/* optional addr displacement */
71	int64_t		immediate;		/* optional immediate operand */
72
73	uint8_t		decoded;	/* set to 1 if successfully decoded */
74
75	struct vie_op	op;			/* opcode description */
76};
77
78/*
79 * Callback functions to read and write memory regions.
80 */
81typedef int (*mem_region_read_t)(void *vm, int cpuid, uint64_t gpa,
82				 uint64_t *rval, int rsize, void *arg);
83
84typedef int (*mem_region_write_t)(void *vm, int cpuid, uint64_t gpa,
85				  uint64_t wval, int wsize, void *arg);
86
87/*
88 * Emulate the decoded 'vie' instruction.
89 *
90 * The callbacks 'mrr' and 'mrw' emulate reads and writes to the memory region
91 * containing 'gpa'. 'mrarg' is an opaque argument that is passed into the
92 * callback functions.
93 *
94 * 'void *vm' should be 'struct vm *' when called from kernel context and
95 * 'struct vmctx *' when called from user context.
96 * s
97 */
98int vmm_emulate_instruction(void *vm, int cpuid, uint64_t gpa, struct vie *vie,
99			    mem_region_read_t mrr, mem_region_write_t mrw,
100			    void *mrarg);
101
102#ifdef _KERNEL
103/*
104 * APIs to fetch and decode the instruction from nested page fault handler.
105 *
106 * 'vie' must be initialized before calling 'vmm_fetch_instruction()'
107 */
108int vmm_fetch_instruction(struct vm *vm, int cpuid,
109			  uint64_t rip, int inst_length, uint64_t cr3,
110			  struct vie *vie);
111
112void vie_init(struct vie *vie);
113
114/*
115 * Decode the instruction fetched into 'vie' so it can be emulated.
116 *
117 * 'gla' is the guest linear address provided by the hardware assist
118 * that caused the nested page table fault. It is used to verify that
119 * the software instruction decoding is in agreement with the hardware.
120 *
121 * Some hardware assists do not provide the 'gla' to the hypervisor.
122 * To skip the 'gla' verification for this or any other reason pass
123 * in VIE_INVALID_GLA instead.
124 */
125#define	VIE_INVALID_GLA		(1UL << 63)	/* a non-canonical address */
126int vmm_decode_instruction(struct vm *vm, int cpuid,
127			   uint64_t gla, struct vie *vie);
128#endif	/* _KERNEL */
129
130#endif	/* _VMM_INSTRUCTION_EMUL_H_ */
131