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Diffstat (limited to 'arch/x86/include/asm/kvm_x86_emulate.h')
| -rw-r--r-- | arch/x86/include/asm/kvm_x86_emulate.h | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/arch/x86/include/asm/kvm_x86_emulate.h b/arch/x86/include/asm/kvm_x86_emulate.h new file mode 100644 index 000000000000..e2d9b030c1ac --- /dev/null +++ b/arch/x86/include/asm/kvm_x86_emulate.h @@ -0,0 +1,184 @@ +/****************************************************************************** + * 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 ASM_X86__KVM_X86_EMULATE_H +#define ASM_X86__KVM_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, void *val, + unsigned int bytes, struct kvm_vcpu *vcpu); + + /* + * 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, + void *val, + unsigned int bytes, + struct kvm_vcpu *vcpu); + + /* + * 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, + const void *val, + unsigned int bytes, + struct kvm_vcpu *vcpu); + + /* + * 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, + const void *old, + const void *new, + unsigned int bytes, + struct kvm_vcpu *vcpu); + +}; + +/* Type, address-of, and value of an instruction's operand. */ +struct operand { + enum { OP_REG, OP_MEM, OP_IMM, OP_NONE } type; + unsigned int bytes; + unsigned long val, orig_val, *ptr; +}; + +struct fetch_cache { + u8 data[15]; + unsigned long start; + unsigned long end; +}; + +struct decode_cache { + u8 twobyte; + u8 b; + u8 lock_prefix; + u8 rep_prefix; + u8 op_bytes; + u8 ad_bytes; + u8 rex_prefix; + struct operand src; + struct operand dst; + bool has_seg_override; + u8 seg_override; + unsigned int d; + unsigned long regs[NR_VCPU_REGS]; + unsigned long eip; + /* modrm */ + u8 modrm; + u8 modrm_mod; + u8 modrm_reg; + u8 modrm_rm; + u8 use_modrm_ea; + bool rip_relative; + unsigned long modrm_ea; + void *modrm_ptr; + unsigned long modrm_val; + struct fetch_cache fetch; +}; + +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; + + /* Emulated execution mode, represented by an X86EMUL_MODE value. */ + int mode; + + u32 cs_base; + + /* decode cache */ + + struct decode_cache decode; +}; + +/* Repeat String Operation Prefix */ +#define REPE_PREFIX 1 +#define REPNE_PREFIX 2 + +/* 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 + +int x86_decode_insn(struct x86_emulate_ctxt *ctxt, + struct x86_emulate_ops *ops); +int x86_emulate_insn(struct x86_emulate_ctxt *ctxt, + struct x86_emulate_ops *ops); + +#endif /* ASM_X86__KVM_X86_EMULATE_H */ |