KVM: x86 emulator: add support for group decoding (e09d082c) · Commits · 戴 / test

arch/x86/kvm/x86_emulate.c

+27 −6

Original line number	Diff line number	Diff line
		@@ -65,6 +65,9 @@
		#define MemAbs (1<<9) /* Memory operand is absolute displacement */
		#define String (1<<10) /* String instruction (rep capable) */
		#define Stack (1<<11) /* Stack instruction (push/pop) */
		#define Group (1<<14) /* Bits 3:5 of modrm byte extend opcode */
		#define GroupDual (1<<15) /* Alternate decoding of mod == 3 */
		#define GroupMask 0xff /* Group number stored in bits 0:7 */

		static u16 opcode_table[256] = {
		/* 0x00 - 0x07 */
		@@ -229,6 +232,12 @@ static u16 twobyte_table[256] = {
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
		};

		static u16 group_table[] = {
		};

		static u16 group2_table[] = {
		};

		/* EFLAGS bit definitions. */
		#define EFLG_OF (1<<11)
		#define EFLG_DF (1<<10)
		@@ -763,7 +772,7 @@ x86_decode_insn(struct x86_emulate_ctxt ctxt, struct x86_emulate_ops ops)
		struct decode_cache *c = &ctxt->decode;
		int rc = 0;
		int mode = ctxt->mode;
		int def_op_bytes, def_ad_bytes;
		int def_op_bytes, def_ad_bytes, group;

		/* Shadow copy of register state. Committed on successful emulation. */

		@@ -864,13 +873,25 @@ done_prefixes:
		c->b = insn_fetch(u8, 1, c->eip);
		c->d = twobyte_table[c->b];
		}
		}

		if (c->d & Group) {
		group = c->d & GroupMask;
		c->modrm = insn_fetch(u8, 1, c->eip);
		--c->eip;

		group = (group << 3) + ((c->modrm >> 3) & 7);
		if ((c->d & GroupDual) && (c->modrm >> 6) == 3)
		c->d = group2_table[group];
		else
		c->d = group_table[group];
		}

		/* Unrecognised? */
		if (c->d == 0) {
		DPRINTF("Cannot emulate %02x\n", c->b);
		return -1;
		}
		}

		if (mode == X86EMUL_MODE_PROT64 && (c->d & Stack))
		c->op_bytes = 8;

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