Commit 0bc5eedb authored by Borislav Petkov's avatar Borislav Petkov Committed by Paolo Bonzini
Browse files

kvm, emulator: Add initial three-byte insns support 



Add initial support for handling three-byte instructions in the
emulator.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent b51e974f

arch/x86/kvm/emulate.c

+30 −0
Original line number Diff line number Diff line
@@ -3892,6 +3892,25 @@ static const struct opcode twobyte_table[256] = { 
	N, N, N, N, N, N, N, N, N, N, N, N, N, N, N, N

};



static const struct gprefix three_byte_0f_38_f0 = {

	N, N, N, N

};



static const struct gprefix three_byte_0f_38_f1 = {

	N, N, N, N

};



/*

 * Insns below are selected by the prefix which indexed by the third opcode

 * byte.

 */

static const struct opcode opcode_map_0f_38[256] = {

	/* 0x00 - 0x7f */

	X16(N), X16(N), X16(N), X16(N), X16(N), X16(N), X16(N), X16(N),

	/* 0x80 - 0xff */

	X16(N), X16(N), X16(N), X16(N), X16(N), X16(N), X16(N), X16(N)

};



#undef D

#undef N

#undef G
@@ -4212,6 +4231,13 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) 
		ctxt->opcode_len = 2;

		ctxt->b = insn_fetch(u8, ctxt);

		opcode = twobyte_table[ctxt->b];



		/* 0F_38 opcode map */

		if (ctxt->b == 0x38) {

			ctxt->opcode_len = 3;

			ctxt->b = insn_fetch(u8, ctxt);

			opcode = opcode_map_0f_38[ctxt->b];

		}

	}

	ctxt->d = opcode.flags;
@@ -4543,6 +4569,8 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt) 


	if (ctxt->opcode_len == 2)

		goto twobyte_insn;

	else if (ctxt->opcode_len == 3)

		goto threebyte_insn;



	switch (ctxt->b) {

	case 0x63:		/* movsxd */
@@ -4727,6 +4755,8 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt) 
		goto cannot_emulate;

	}



threebyte_insn:



	if (rc != X86EMUL_CONTINUE)

		goto done;