freebsd-skq/sys/amd64/include/vmm_instruction_emul.h
Conrad Meyer 4daa95f85d bhyve(8): For prototyping, reattempt decode in userspace
If userspace has a newer bhyve than the kernel, it may be able to decode
and emulate some instructions vmm.ko is unaware of.  In this scenario,
reset decoder state and try again.

Reviewed by:	grehan
Differential Revision:	https://reviews.freebsd.org/D24464
2020-06-25 00:18:42 +00:00

136 lines
5.0 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* 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_
#include <sys/mman.h>
/*
* 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,
struct vm_guest_paging *paging, mem_region_read_t mrr,
mem_region_write_t mrw, void *mrarg);
int vie_update_register(void *vm, int vcpuid, enum vm_reg_name reg,
uint64_t val, int size);
/*
* Returns 1 if an alignment check exception should be injected and 0 otherwise.
*/
int vie_alignment_check(int cpl, int operand_size, uint64_t cr0,
uint64_t rflags, uint64_t gla);
/* Returns 1 if the 'gla' is not canonical and 0 otherwise. */
int vie_canonical_check(enum vm_cpu_mode cpu_mode, uint64_t gla);
uint64_t vie_size2mask(int size);
int vie_calculate_gla(enum vm_cpu_mode cpu_mode, enum vm_reg_name seg,
struct seg_desc *desc, uint64_t off, int length, int addrsize, int prot,
uint64_t *gla);
#ifdef _KERNEL
/*
* APIs to fetch and decode the instruction from nested page fault handler.
*
* 'vie' must be initialized before calling 'vmm_fetch_instruction()'
*/
int vmm_fetch_instruction(struct vm *vm, int cpuid,
struct vm_guest_paging *guest_paging,
uint64_t rip, int inst_length, struct vie *vie,
int *is_fault);
/*
* Translate the guest linear address 'gla' to a guest physical address.
*
* retval is_fault Interpretation
* 0 0 'gpa' contains result of the translation
* 0 1 An exception was injected into the guest
* EFAULT N/A An unrecoverable hypervisor error occurred
*/
int vm_gla2gpa(struct vm *vm, int vcpuid, struct vm_guest_paging *paging,
uint64_t gla, int prot, uint64_t *gpa, int *is_fault);
/*
* Like vm_gla2gpa, but no exceptions are injected into the guest and
* PTEs are not changed.
*/
int vm_gla2gpa_nofault(struct vm *vm, int vcpuid, struct vm_guest_paging *paging,
uint64_t gla, int prot, uint64_t *gpa, int *is_fault);
#endif /* _KERNEL */
void vie_restart(struct vie *vie);
void vie_init(struct vie *vie, const char *inst_bytes, int inst_length);
/*
* 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.
*/
#ifdef _KERNEL
#define VIE_INVALID_GLA (1UL << 63) /* a non-canonical address */
int vmm_decode_instruction(struct vm *vm, int cpuid, uint64_t gla,
enum vm_cpu_mode cpu_mode, int csd, struct vie *vie);
#else /* !_KERNEL */
/*
* Permit instruction decoding logic to be compiled outside of the kernel for
* rapid iteration and validation. No GLA validation is performed, obviously.
*/
int vmm_decode_instruction(enum vm_cpu_mode cpu_mode, int csd,
struct vie *vie);
#endif /* _KERNEL */
#endif /* _VMM_INSTRUCTION_EMUL_H_ */