forked from Minki/linux
c3cd7ffaf5
Currently emulator returns -1 when emulation failed or IO is needed. Caller tries to guess whether emulation failed by looking at other variables. Make it easier for caller to recognise error condition by always returning -1 in case of failure. For this new emulator internal return value X86EMUL_IO_NEEDED is introduced. It is used to distinguish between error condition (which returns X86EMUL_UNHANDLEABLE) and condition that requires IO exit to userspace to continue emulation. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
249 lines
8.7 KiB
C
249 lines
8.7 KiB
C
/******************************************************************************
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* x86_emulate.h
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*
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* Generic x86 (32-bit and 64-bit) instruction decoder and emulator.
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*
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* Copyright (c) 2005 Keir Fraser
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*
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* From: xen-unstable 10676:af9809f51f81a3c43f276f00c81a52ef558afda4
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*/
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#ifndef _ASM_X86_KVM_X86_EMULATE_H
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#define _ASM_X86_KVM_X86_EMULATE_H
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#include <asm/desc_defs.h>
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struct x86_emulate_ctxt;
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/*
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* x86_emulate_ops:
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*
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* These operations represent the instruction emulator's interface to memory.
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* There are two categories of operation: those that act on ordinary memory
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* regions (*_std), and those that act on memory regions known to require
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* special treatment or emulation (*_emulated).
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*
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* The emulator assumes that an instruction accesses only one 'emulated memory'
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* location, that this location is the given linear faulting address (cr2), and
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* that this is one of the instruction's data operands. Instruction fetches and
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* stack operations are assumed never to access emulated memory. The emulator
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* automatically deduces which operand of a string-move operation is accessing
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* emulated memory, and assumes that the other operand accesses normal memory.
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*
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* NOTES:
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* 1. The emulator isn't very smart about emulated vs. standard memory.
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* 'Emulated memory' access addresses should be checked for sanity.
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* 'Normal memory' accesses may fault, and the caller must arrange to
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* detect and handle reentrancy into the emulator via recursive faults.
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* Accesses may be unaligned and may cross page boundaries.
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* 2. If the access fails (cannot emulate, or a standard access faults) then
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* it is up to the memop to propagate the fault to the guest VM via
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* some out-of-band mechanism, unknown to the emulator. The memop signals
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* failure by returning X86EMUL_PROPAGATE_FAULT to the emulator, which will
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* then immediately bail.
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* 3. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only
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* cmpxchg8b_emulated need support 8-byte accesses.
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* 4. The emulator cannot handle 64-bit mode emulation on an x86/32 system.
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*/
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/* Access completed successfully: continue emulation as normal. */
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#define X86EMUL_CONTINUE 0
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/* Access is unhandleable: bail from emulation and return error to caller. */
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#define X86EMUL_UNHANDLEABLE 1
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/* Terminate emulation but return success to the caller. */
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#define X86EMUL_PROPAGATE_FAULT 2 /* propagate a generated fault to guest */
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#define X86EMUL_RETRY_INSTR 3 /* retry the instruction for some reason */
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#define X86EMUL_CMPXCHG_FAILED 4 /* cmpxchg did not see expected value */
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#define X86EMUL_IO_NEEDED 5 /* IO is needed to complete emulation */
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struct x86_emulate_ops {
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/*
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* read_std: Read bytes of standard (non-emulated/special) memory.
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* Used for descriptor reading.
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* @addr: [IN ] Linear address from which to read.
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* @val: [OUT] Value read from memory, zero-extended to 'u_long'.
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* @bytes: [IN ] Number of bytes to read from memory.
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*/
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int (*read_std)(unsigned long addr, void *val,
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unsigned int bytes, struct kvm_vcpu *vcpu, u32 *error);
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/*
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* write_std: Write bytes of standard (non-emulated/special) memory.
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* Used for descriptor writing.
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* @addr: [IN ] Linear address to which to write.
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* @val: [OUT] Value write to memory, zero-extended to 'u_long'.
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* @bytes: [IN ] Number of bytes to write to memory.
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*/
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int (*write_std)(unsigned long addr, void *val,
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unsigned int bytes, struct kvm_vcpu *vcpu, u32 *error);
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/*
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* fetch: Read bytes of standard (non-emulated/special) memory.
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* Used for instruction fetch.
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* @addr: [IN ] Linear address from which to read.
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* @val: [OUT] Value read from memory, zero-extended to 'u_long'.
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* @bytes: [IN ] Number of bytes to read from memory.
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*/
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int (*fetch)(unsigned long addr, void *val,
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unsigned int bytes, struct kvm_vcpu *vcpu, u32 *error);
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/*
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* read_emulated: Read bytes from emulated/special memory area.
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* @addr: [IN ] Linear address from which to read.
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* @val: [OUT] Value read from memory, zero-extended to 'u_long'.
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* @bytes: [IN ] Number of bytes to read from memory.
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*/
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int (*read_emulated)(unsigned long addr,
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void *val,
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unsigned int bytes,
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struct kvm_vcpu *vcpu);
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/*
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* write_emulated: Write bytes to emulated/special memory area.
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* @addr: [IN ] Linear address to which to write.
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* @val: [IN ] Value to write to memory (low-order bytes used as
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* required).
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* @bytes: [IN ] Number of bytes to write to memory.
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*/
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int (*write_emulated)(unsigned long addr,
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const void *val,
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unsigned int bytes,
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struct kvm_vcpu *vcpu);
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/*
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* cmpxchg_emulated: Emulate an atomic (LOCKed) CMPXCHG operation on an
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* emulated/special memory area.
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* @addr: [IN ] Linear address to access.
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* @old: [IN ] Value expected to be current at @addr.
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* @new: [IN ] Value to write to @addr.
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* @bytes: [IN ] Number of bytes to access using CMPXCHG.
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*/
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int (*cmpxchg_emulated)(unsigned long addr,
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const void *old,
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const void *new,
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unsigned int bytes,
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struct kvm_vcpu *vcpu);
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int (*pio_in_emulated)(int size, unsigned short port, void *val,
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unsigned int count, struct kvm_vcpu *vcpu);
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int (*pio_out_emulated)(int size, unsigned short port, const void *val,
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unsigned int count, struct kvm_vcpu *vcpu);
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bool (*get_cached_descriptor)(struct desc_struct *desc,
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int seg, struct kvm_vcpu *vcpu);
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void (*set_cached_descriptor)(struct desc_struct *desc,
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int seg, struct kvm_vcpu *vcpu);
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u16 (*get_segment_selector)(int seg, struct kvm_vcpu *vcpu);
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void (*set_segment_selector)(u16 sel, int seg, struct kvm_vcpu *vcpu);
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unsigned long (*get_cached_segment_base)(int seg, struct kvm_vcpu *vcpu);
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void (*get_gdt)(struct desc_ptr *dt, struct kvm_vcpu *vcpu);
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ulong (*get_cr)(int cr, struct kvm_vcpu *vcpu);
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int (*set_cr)(int cr, ulong val, struct kvm_vcpu *vcpu);
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int (*cpl)(struct kvm_vcpu *vcpu);
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void (*set_rflags)(struct kvm_vcpu *vcpu, unsigned long rflags);
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int (*get_dr)(int dr, unsigned long *dest, struct kvm_vcpu *vcpu);
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int (*set_dr)(int dr, unsigned long value, struct kvm_vcpu *vcpu);
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int (*set_msr)(struct kvm_vcpu *vcpu, u32 msr_index, u64 data);
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int (*get_msr)(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata);
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};
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/* Type, address-of, and value of an instruction's operand. */
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struct operand {
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enum { OP_REG, OP_MEM, OP_IMM, OP_NONE } type;
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unsigned int bytes;
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unsigned long orig_val, *ptr;
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union {
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unsigned long val;
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char valptr[sizeof(unsigned long) + 2];
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};
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};
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struct fetch_cache {
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u8 data[15];
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unsigned long start;
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unsigned long end;
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};
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struct read_cache {
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u8 data[1024];
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unsigned long pos;
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unsigned long end;
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};
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struct decode_cache {
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u8 twobyte;
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u8 b;
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u8 lock_prefix;
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u8 rep_prefix;
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u8 op_bytes;
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u8 ad_bytes;
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u8 rex_prefix;
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struct operand src;
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struct operand src2;
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struct operand dst;
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bool has_seg_override;
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u8 seg_override;
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unsigned int d;
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unsigned long regs[NR_VCPU_REGS];
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unsigned long eip;
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/* modrm */
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u8 modrm;
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u8 modrm_mod;
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u8 modrm_reg;
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u8 modrm_rm;
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u8 use_modrm_ea;
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bool rip_relative;
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unsigned long modrm_ea;
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void *modrm_ptr;
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unsigned long modrm_val;
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struct fetch_cache fetch;
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struct read_cache io_read;
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struct read_cache mem_read;
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};
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struct x86_emulate_ctxt {
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/* Register state before/after emulation. */
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struct kvm_vcpu *vcpu;
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unsigned long eflags;
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unsigned long eip; /* eip before instruction emulation */
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/* Emulated execution mode, represented by an X86EMUL_MODE value. */
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int mode;
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u32 cs_base;
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/* interruptibility state, as a result of execution of STI or MOV SS */
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int interruptibility;
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bool restart; /* restart string instruction after writeback */
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/* decode cache */
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struct decode_cache decode;
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};
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/* Repeat String Operation Prefix */
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#define REPE_PREFIX 1
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#define REPNE_PREFIX 2
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/* Execution mode, passed to the emulator. */
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#define X86EMUL_MODE_REAL 0 /* Real mode. */
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#define X86EMUL_MODE_VM86 1 /* Virtual 8086 mode. */
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#define X86EMUL_MODE_PROT16 2 /* 16-bit protected mode. */
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#define X86EMUL_MODE_PROT32 4 /* 32-bit protected mode. */
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#define X86EMUL_MODE_PROT64 8 /* 64-bit (long) mode. */
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/* Host execution mode. */
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#if defined(CONFIG_X86_32)
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#define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
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#elif defined(CONFIG_X86_64)
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#define X86EMUL_MODE_HOST X86EMUL_MODE_PROT64
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#endif
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int x86_decode_insn(struct x86_emulate_ctxt *ctxt,
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struct x86_emulate_ops *ops);
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int x86_emulate_insn(struct x86_emulate_ctxt *ctxt,
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struct x86_emulate_ops *ops);
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int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
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struct x86_emulate_ops *ops,
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u16 tss_selector, int reason,
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bool has_error_code, u32 error_code);
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#endif /* _ASM_X86_KVM_X86_EMULATE_H */
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