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+/******************************************************************************
+ * 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 */