/****************************************************************************** * 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 */