freebsd-dev/sys/amd64/include/vmm_instruction_emul.h
Neel Natu 66f71b7d24 Allow caller to skip 'guest linear address' validation when doing instruction
decode. This is to accomodate hardware assist implementations that do not
provide the 'guest linear address' as part of nested page fault collateral.

Submitted by:	Anish Gupta (akgupt3 at gmail dot com)
2013-03-28 21:26:19 +00:00

127 lines
4.2 KiB
C

/*-
* Copyright (c) 2012 NetApp, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _VMM_INSTRUCTION_EMUL_H_
#define _VMM_INSTRUCTION_EMUL_H_
/*
* The data structures 'vie' and 'vie_op' are meant to be opaque to the
* consumers of instruction decoding. The only reason why their contents
* need to be exposed is because they are part of the 'vm_exit' structure.
*/
struct vie_op {
uint8_t op_byte; /* actual opcode byte */
uint8_t op_type; /* type of operation (e.g. MOV) */
uint16_t op_flags;
};
#define VIE_INST_SIZE 15
struct vie {
uint8_t inst[VIE_INST_SIZE]; /* instruction bytes */
uint8_t num_valid; /* size of the instruction */
uint8_t num_processed;
uint8_t rex_w:1, /* REX prefix */
rex_r:1,
rex_x:1,
rex_b:1,
rex_present:1;
uint8_t mod:2, /* ModRM byte */
reg:4,
rm:4;
uint8_t ss:2, /* SIB byte */
index:4,
base:4;
uint8_t disp_bytes;
uint8_t imm_bytes;
uint8_t scale;
int base_register; /* VM_REG_GUEST_xyz */
int index_register; /* VM_REG_GUEST_xyz */
int64_t displacement; /* optional addr displacement */
int64_t immediate; /* optional immediate operand */
uint8_t decoded; /* set to 1 if successfully decoded */
struct vie_op op; /* opcode description */
};
/*
* Callback functions to read and write memory regions.
*/
typedef int (*mem_region_read_t)(void *vm, int cpuid, uint64_t gpa,
uint64_t *rval, int rsize, void *arg);
typedef int (*mem_region_write_t)(void *vm, int cpuid, uint64_t gpa,
uint64_t wval, int wsize, void *arg);
/*
* Emulate the decoded 'vie' instruction.
*
* The callbacks 'mrr' and 'mrw' emulate reads and writes to the memory region
* containing 'gpa'. 'mrarg' is an opaque argument that is passed into the
* callback functions.
*
* 'void *vm' should be 'struct vm *' when called from kernel context and
* 'struct vmctx *' when called from user context.
* s
*/
int vmm_emulate_instruction(void *vm, int cpuid, uint64_t gpa, struct vie *vie,
mem_region_read_t mrr, mem_region_write_t mrw,
void *mrarg);
#ifdef _KERNEL
/*
* APIs to fetch and decode the instruction from nested page fault handler.
*/
int vmm_fetch_instruction(struct vm *vm, int cpuid,
uint64_t rip, int inst_length, uint64_t cr3,
struct vie *vie);
/*
* Decode the instruction fetched into 'vie' so it can be emulated.
*
* 'gla' is the guest linear address provided by the hardware assist
* that caused the nested page table fault. It is used to verify that
* the software instruction decoding is in agreement with the hardware.
*
* Some hardware assists do not provide the 'gla' to the hypervisor.
* To skip the 'gla' verification for this or any other reason pass
* in VIE_INVALID_GLA instead.
*/
#define VIE_INVALID_GLA (1UL << 63) /* a non-canonical address */
int vmm_decode_instruction(struct vm *vm, int cpuid,
uint64_t gla, struct vie *vie);
#endif /* _KERNEL */
#endif /* _VMM_INSTRUCTION_EMUL_H_ */