KVM: x86 emulator: consolidate immediate decode into a function (39f21ee5) · Commits · e / devices / android_kernel_fairphone_FP5

arch/x86/kvm/emulate.c

+64 −45

Original line number	Diff line number	Diff line
		@@ -2541,6 +2541,55 @@ static struct opcode twobyte_table[256] = {
		#undef GD
		#undef I

		static unsigned imm_size(struct decode_cache *c)
		{
		unsigned size;

		size = (c->d & ByteOp) ? 1 : c->op_bytes;
		if (size == 8)
		size = 4;
		return size;
		}

		static int decode_imm(struct x86_emulate_ctxt ctxt, struct operand op,
		unsigned size, bool sign_extension)
		{
		struct decode_cache *c = &ctxt->decode;
		struct x86_emulate_ops *ops = ctxt->ops;
		int rc = X86EMUL_CONTINUE;

		op->type = OP_IMM;
		op->bytes = size;
		op->addr.mem = c->eip;
		/* NB. Immediates are sign-extended as necessary. */
		switch (op->bytes) {
		case 1:
		op->val = insn_fetch(s8, 1, c->eip);
		break;
		case 2:
		op->val = insn_fetch(s16, 2, c->eip);
		break;
		case 4:
		op->val = insn_fetch(s32, 4, c->eip);
		break;
		}
		if (!sign_extension) {
		switch (op->bytes) {
		case 1:
		op->val &= 0xff;
		break;
		case 2:
		op->val &= 0xffff;
		break;
		case 4:
		op->val &= 0xffffffff;
		break;
		}
		}
		done:
		return rc;
		}

		int
		x86_decode_insn(struct x86_emulate_ctxt *ctxt)
		{
		@@ -2730,52 +2779,19 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt)
		c->src = memop;
		break;
		case SrcImmU16:
		c->src.bytes = 2;
		goto srcimm;
		case SrcImm:
		case SrcImmU:
		c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
		if (c->src.bytes == 8)
		c->src.bytes = 4;
		srcimm:
		c->src.type = OP_IMM;
		c->src.addr.mem = c->eip;
		/* NB. Immediates are sign-extended as necessary. */
		switch (c->src.bytes) {
		case 1:
		c->src.val = insn_fetch(s8, 1, c->eip);
		break;
		case 2:
		c->src.val = insn_fetch(s16, 2, c->eip);
		rc = decode_imm(ctxt, &c->src, 2, false);
		break;
		case 4:
		c->src.val = insn_fetch(s32, 4, c->eip);
		break;
		}
		if ((c->d & SrcMask) == SrcImmU
		\|\| (c->d & SrcMask) == SrcImmU16) {
		switch (c->src.bytes) {
		case 1:
		c->src.val &= 0xff;
		break;
		case 2:
		c->src.val &= 0xffff;
		break;
		case 4:
		c->src.val &= 0xffffffff;
		case SrcImm:
		rc = decode_imm(ctxt, &c->src, imm_size(c), true);
		break;
		}
		}
		case SrcImmU:
		rc = decode_imm(ctxt, &c->src, imm_size(c), false);
		break;
		case SrcImmByte:
		rc = decode_imm(ctxt, &c->src, 1, true);
		break;
		case SrcImmUByte:
		c->src.type = OP_IMM;
		c->src.addr.mem = c->eip;
		c->src.bytes = 1;
		if ((c->d & SrcMask) == SrcImmByte)
		c->src.val = insn_fetch(s8, 1, c->eip);
		else
		c->src.val = insn_fetch(u8, 1, c->eip);
		rc = decode_imm(ctxt, &c->src, 1, false);
		break;
		case SrcAcc:
		c->src.type = OP_REG;
		@@ -2807,6 +2823,9 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt)
		break;
		}

		if (rc != X86EMUL_CONTINUE)
		goto done;

		/*
		* Decode and fetch the second source operand: register, memory
		* or immediate.
		@@ -2819,10 +2838,7 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt)
		c->src2.val = c->regs[VCPU_REGS_RCX] & 0x8;
		break;
		case Src2ImmByte:
		c->src2.type = OP_IMM;
		c->src2.addr.mem = c->eip;
		c->src2.bytes = 1;
		c->src2.val = insn_fetch(u8, 1, c->eip);
		rc = decode_imm(ctxt, &c->src2, 1, true);
		break;
		case Src2One:
		c->src2.bytes = 1;
		@@ -2830,6 +2846,9 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt)
		break;
		}

		if (rc != X86EMUL_CONTINUE)
		goto done;

		/* Decode and fetch the destination operand: register or memory. */
		switch (c->d & DstMask) {
		case DstReg: