[deliverable/linux.git] / drivers / kvm / x86_emulate.h

/******************************************************************************
 * x86_emulate.h
 *
 * Generic x86 (32-bit and 64-bit) instruction decoder and emulator.
 *
 * Copyright (c) 2005 Keir Fraser
 *
 * From: xen-unstable 10676:af9809f51f81a3c43f276f00c81a52ef558afda4
 */

#ifndef __X86_EMULATE_H__
#define __X86_EMULATE_H__

struct x86_emulate_ctxt;

/*
 * x86_emulate_ops:
 *
 * These operations represent the instruction emulator's interface to memory.
 * There are two categories of operation: those that act on ordinary memory
 * regions (*_std), and those that act on memory regions known to require
 * special treatment or emulation (*_emulated).
 *
 * The emulator assumes that an instruction accesses only one 'emulated memory'
 * location, that this location is the given linear faulting address (cr2), and
 * that this is one of the instruction's data operands. Instruction fetches and
 * stack operations are assumed never to access emulated memory. The emulator
 * automatically deduces which operand of a string-move operation is accessing
 * emulated memory, and assumes that the other operand accesses normal memory.
 *
 * NOTES:
 *  1. The emulator isn't very smart about emulated vs. standard memory.
 *     'Emulated memory' access addresses should be checked for sanity.
 *     'Normal memory' accesses may fault, and the caller must arrange to
 *     detect and handle reentrancy into the emulator via recursive faults.
 *     Accesses may be unaligned and may cross page boundaries.
 *  2. If the access fails (cannot emulate, or a standard access faults) then
 *     it is up to the memop to propagate the fault to the guest VM via
 *     some out-of-band mechanism, unknown to the emulator. The memop signals
 *     failure by returning X86EMUL_PROPAGATE_FAULT to the emulator, which will
 *     then immediately bail.
 *  3. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only
 *     cmpxchg8b_emulated need support 8-byte accesses.
 *  4. The emulator cannot handle 64-bit mode emulation on an x86/32 system.
 */
/* Access completed successfully: continue emulation as normal. */
#define X86EMUL_CONTINUE        0
/* Access is unhandleable: bail from emulation and return error to caller. */
#define X86EMUL_UNHANDLEABLE    1
/* Terminate emulation but return success to the caller. */
#define X86EMUL_PROPAGATE_FAULT 2 /* propagate a generated fault to guest */
#define X86EMUL_RETRY_INSTR     2 /* retry the instruction for some reason */
#define X86EMUL_CMPXCHG_FAILED  2 /* cmpxchg did not see expected value */
struct x86_emulate_ops {
	/*
	 * read_std: Read bytes of standard (non-emulated/special) memory.
	 *           Used for instruction fetch, stack operations, and others.
	 *  @addr:  [IN ] Linear address from which to read.
	 *  @val:   [OUT] Value read from memory, zero-extended to 'u_long'.
	 *  @bytes: [IN ] Number of bytes to read from memory.
	 */
	int (*read_std)(unsigned long addr,
			unsigned long *val,
			unsigned int bytes, struct x86_emulate_ctxt * ctxt);

	/*
	 * write_std: Write bytes of standard (non-emulated/special) memory.
	 *            Used for stack operations, and others.
	 *  @addr:  [IN ] Linear address to which to write.
	 *  @val:   [IN ] Value to write to memory (low-order bytes used as
	 *                required).
	 *  @bytes: [IN ] Number of bytes to write to memory.
	 */
	int (*write_std)(unsigned long addr,
			 unsigned long val,
			 unsigned int bytes, struct x86_emulate_ctxt * ctxt);

	/*
	 * read_emulated: Read bytes from emulated/special memory area.
	 *  @addr:  [IN ] Linear address from which to read.
	 *  @val:   [OUT] Value read from memory, zero-extended to 'u_long'.
	 *  @bytes: [IN ] Number of bytes to read from memory.
	 */
	int (*read_emulated) (unsigned long addr,
			      unsigned long *val,
			      unsigned int bytes,
			      struct x86_emulate_ctxt * ctxt);

	/*
	 * write_emulated: Read bytes from emulated/special memory area.
	 *  @addr:  [IN ] Linear address to which to write.
	 *  @val:   [IN ] Value to write to memory (low-order bytes used as
	 *                required).
	 *  @bytes: [IN ] Number of bytes to write to memory.
	 */
	int (*write_emulated) (unsigned long addr,
			       unsigned long val,
			       unsigned int bytes,
			       struct x86_emulate_ctxt * ctxt);

	/*
	 * cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an
	 *                   emulated/special memory area.
	 *  @addr:  [IN ] Linear address to access.
	 *  @old:   [IN ] Value expected to be current at @addr.
	 *  @new:   [IN ] Value to write to @addr.
	 *  @bytes: [IN ] Number of bytes to access using CMPXCHG.
	 */
	int (*cmpxchg_emulated) (unsigned long addr,
				 unsigned long old,
				 unsigned long new,
				 unsigned int bytes,
				 struct x86_emulate_ctxt * ctxt);

	/*
	 * cmpxchg8b_emulated: Emulate an atomic (LOCKed) CMPXCHG8B operation on an
	 *                     emulated/special memory area.
	 *  @addr:  [IN ] Linear address to access.
	 *  @old:   [IN ] Value expected to be current at @addr.
	 *  @new:   [IN ] Value to write to @addr.
	 * NOTES:
	 *  1. This function is only ever called when emulating a real CMPXCHG8B.
	 *  2. This function is *never* called on x86/64 systems.
	 *  2. Not defining this function (i.e., specifying NULL) is equivalent
	 *     to defining a function that always returns X86EMUL_UNHANDLEABLE.
	 */
	int (*cmpxchg8b_emulated) (unsigned long addr,
				   unsigned long old_lo,
				   unsigned long old_hi,
				   unsigned long new_lo,
				   unsigned long new_hi,
				   struct x86_emulate_ctxt * ctxt);
};

struct cpu_user_regs;

struct x86_emulate_ctxt {
	/* Register state before/after emulation. */
	struct kvm_vcpu *vcpu;

	/* Linear faulting address (if emulating a page-faulting instruction). */
	unsigned long eflags;
	unsigned long cr2;

	/* Emulated execution mode, represented by an X86EMUL_MODE value. */
	int mode;

	unsigned long cs_base;
	unsigned long ds_base;
	unsigned long es_base;
	unsigned long ss_base;
	unsigned long gs_base;
	unsigned long fs_base;
};

/* Execution mode, passed to the emulator. */
#define X86EMUL_MODE_REAL     0	/* Real mode.             */
#define X86EMUL_MODE_PROT16   2	/* 16-bit protected mode. */
#define X86EMUL_MODE_PROT32   4	/* 32-bit protected mode. */
#define X86EMUL_MODE_PROT64   8	/* 64-bit (long) mode.    */

/* Host execution mode. */
#if defined(__i386__)
#define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
#elif defined(CONFIG_X86_64)
#define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64
#endif

/*
 * x86_emulate_memop: Emulate an instruction that faulted attempting to
 *                    read/write a 'special' memory area.
 * Returns -1 on failure, 0 on success.
 */
int x86_emulate_memop(struct x86_emulate_ctxt *ctxt,
		      struct x86_emulate_ops *ops);

/*
 * Given the 'reg' portion of a ModRM byte, and a register block, return a
 * pointer into the block that addresses the relevant register.
 * @highbyte_regs specifies whether to decode AH,CH,DH,BH.
 */
void *decode_register(u8 modrm_reg, unsigned long *regs,
		      int highbyte_regs);

#endif				/* __X86_EMULATE_H__ */
Commit	Line	Data
6aa8b732 AK	1	/******************************************************************************
	2	* x86_emulate.h
	3	*
	4	* Generic x86 (32-bit and 64-bit) instruction decoder and emulator.
	5	*
	6	* Copyright (c) 2005 Keir Fraser
	7	*
	8	* From: xen-unstable 10676:af9809f51f81a3c43f276f00c81a52ef558afda4
	9	*/
	10
	11	#ifndef __X86_EMULATE_H__
	12	#define __X86_EMULATE_H__
	13
	14	struct x86_emulate_ctxt;
	15
	16	/*
	17	* x86_emulate_ops:
	18	*
	19	* These operations represent the instruction emulator's interface to memory.
	20	* There are two categories of operation: those that act on ordinary memory
	21	* regions (*_std), and those that act on memory regions known to require
	22	* special treatment or emulation (*_emulated).
	23	*
	24	* The emulator assumes that an instruction accesses only one 'emulated memory'
	25	* location, that this location is the given linear faulting address (cr2), and
	26	* that this is one of the instruction's data operands. Instruction fetches and
	27	* stack operations are assumed never to access emulated memory. The emulator
	28	* automatically deduces which operand of a string-move operation is accessing
	29	* emulated memory, and assumes that the other operand accesses normal memory.
	30	*
	31	* NOTES:
	32	* 1. The emulator isn't very smart about emulated vs. standard memory.
	33	* 'Emulated memory' access addresses should be checked for sanity.
	34	* 'Normal memory' accesses may fault, and the caller must arrange to
	35	* detect and handle reentrancy into the emulator via recursive faults.
	36	* Accesses may be unaligned and may cross page boundaries.
	37	* 2. If the access fails (cannot emulate, or a standard access faults) then
	38	* it is up to the memop to propagate the fault to the guest VM via
	39	* some out-of-band mechanism, unknown to the emulator. The memop signals
	40	* failure by returning X86EMUL_PROPAGATE_FAULT to the emulator, which will
	41	* then immediately bail.
	42	* 3. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only
	43	* cmpxchg8b_emulated need support 8-byte accesses.
	44	* 4. The emulator cannot handle 64-bit mode emulation on an x86/32 system.
	45	*/
	46	/* Access completed successfully: continue emulation as normal. */
	47	#define X86EMUL_CONTINUE 0
	48	/* Access is unhandleable: bail from emulation and return error to caller. */
	49	#define X86EMUL_UNHANDLEABLE 1
	50	/* Terminate emulation but return success to the caller. */
	51	#define X86EMUL_PROPAGATE_FAULT 2 /* propagate a generated fault to guest */
	52	#define X86EMUL_RETRY_INSTR 2 /* retry the instruction for some reason */
	53	#define X86EMUL_CMPXCHG_FAILED 2 /* cmpxchg did not see expected value */
	54	struct x86_emulate_ops {
	55	/*
	56	* read_std: Read bytes of standard (non-emulated/special) memory.
	57	* Used for instruction fetch, stack operations, and others.
	58	* @addr: [IN ] Linear address from which to read.
	59	* @val: [OUT] Value read from memory, zero-extended to 'u_long'.
	60	* @bytes: [IN ] Number of bytes to read from memory.
	61	*/
	62	int (*read_std)(unsigned long addr,
	63	unsigned long *val,
	64	unsigned int bytes, struct x86_emulate_ctxt * ctxt);
65
66	/*
67	* write_std: Write bytes of standard (non-emulated/special) memory.
68	* Used for stack operations, and others.
69	* @addr: [IN ] Linear address to which to write.
70	* @val: [IN ] Value to write to memory (low-order bytes used as
71	* required).
72	* @bytes: [IN ] Number of bytes to write to memory.
73	*/
74	int (*write_std)(unsigned long addr,
75	unsigned long val,
76	unsigned int bytes, struct x86_emulate_ctxt * ctxt);
77
78	/*
79	* read_emulated: Read bytes from emulated/special memory area.
80	* @addr: [IN ] Linear address from which to read.
81	* @val: [OUT] Value read from memory, zero-extended to 'u_long'.
82	* @bytes: [IN ] Number of bytes to read from memory.
83	*/
84	int (*read_emulated) (unsigned long addr,
85	unsigned long *val,
86	unsigned int bytes,
87	struct x86_emulate_ctxt * ctxt);
88
89	/*
90	* write_emulated: Read bytes from emulated/special memory area.
91	* @addr: [IN ] Linear address to which to write.
92	* @val: [IN ] Value to write to memory (low-order bytes used as
93	* required).
94	* @bytes: [IN ] Number of bytes to write to memory.
95	*/
96	int (*write_emulated) (unsigned long addr,
97	unsigned long val,
98	unsigned int bytes,
99	struct x86_emulate_ctxt * ctxt);
100
101	/*
102	* cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an
103	* emulated/special memory area.
104	* @addr: [IN ] Linear address to access.
105	* @old: [IN ] Value expected to be current at @addr.
106	* @new: [IN ] Value to write to @addr.
107	* @bytes: [IN ] Number of bytes to access using CMPXCHG.
108	*/
109	int (*cmpxchg_emulated) (unsigned long addr,
110	unsigned long old,
111	unsigned long new,
112	unsigned int bytes,
113	struct x86_emulate_ctxt * ctxt);
114
115	/*
116	* cmpxchg8b_emulated: Emulate an atomic (LOCKed) CMPXCHG8B operation on an
117	* emulated/special memory area.
118	* @addr: [IN ] Linear address to access.
119	* @old: [IN ] Value expected to be current at @addr.
120	* @new: [IN ] Value to write to @addr.
121	* NOTES:
122	* 1. This function is only ever called when emulating a real CMPXCHG8B.
123	* 2. This function is never called on x86/64 systems.
124	* 2. Not defining this function (i.e., specifying NULL) is equivalent
125	* to defining a function that always returns X86EMUL_UNHANDLEABLE.
126	*/
127	int (*cmpxchg8b_emulated) (unsigned long addr,
128	unsigned long old_lo,
129	unsigned long old_hi,
130	unsigned long new_lo,
131	unsigned long new_hi,
132	struct x86_emulate_ctxt * ctxt);
133	};
134
135	struct cpu_user_regs;
136
137	struct x86_emulate_ctxt {
138	/* Register state before/after emulation. */
139	struct kvm_vcpu *vcpu;
140
141	/* Linear faulting address (if emulating a page-faulting instruction). */
142	unsigned long eflags;
143	unsigned long cr2;
144
145	/* Emulated execution mode, represented by an X86EMUL_MODE value. */
146	int mode;
147
148	unsigned long cs_base;
149	unsigned long ds_base;
150	unsigned long es_base;
151	unsigned long ss_base;
152	unsigned long gs_base;
153	unsigned long fs_base;
154	};
155
156	/* Execution mode, passed to the emulator. */
157	#define X86EMUL_MODE_REAL 0 /* Real mode. */
158	#define X86EMUL_MODE_PROT16 2 /* 16-bit protected mode. */
159	#define X86EMUL_MODE_PROT32 4 /* 32-bit protected mode. */
160	#define X86EMUL_MODE_PROT64 8 /* 64-bit (long) mode. */
161
162	/* Host execution mode. */
163	#if defined(__i386__)
164	#define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
05b3e0c2	165	#elif defined(CONFIG_X86_64)
6aa8b732 AK	166	#define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64
	167	#endif
	168
	169	/*
	170	* x86_emulate_memop: Emulate an instruction that faulted attempting to
	171	* read/write a 'special' memory area.
	172	* Returns -1 on failure, 0 on success.
	173	*/
	174	int x86_emulate_memop(struct x86_emulate_ctxt *ctxt,
	175	struct x86_emulate_ops *ops);
	176
	177	/*
	178	* Given the 'reg' portion of a ModRM byte, and a register block, return a
	179	* pointer into the block that addresses the relevant register.
	180	* @highbyte_regs specifies whether to decode AH,CH,DH,BH.
	181	*/
	182	void decode_register(u8 modrm_reg, unsigned long regs,
	183	int highbyte_regs);
	184
	185	#endif /* __X86_EMULATE_H__ */