Commit 7e11eec9 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Sean Christopherson
Browse files

KVM: x86: Share emulator's common register decoding code 



Remove all duplicate handling of register operands, including picking
the right register class and fetching it, by extracting a new function
that can be used for both REG and MODRM operands.

Centralize setting op->orig_val = op->val in fetch_register_operand()
as well.

No functional change intended.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: default avatarChang S. Bae <chang.seok.bae@intel.com>
Link: https://patch.msgid.link/20251114003633.60689-6-pbonzini@redhat.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 1a84b07a

arch/x86/kvm/emulate.c

+17 −32
Original line number Diff line number Diff line
@@ -1026,6 +1026,7 @@ static void fetch_register_operand(struct operand *op) 
		op->val = *(u64 *)op->addr.reg;

		break;

	}

	op->orig_val = op->val;

}



static int em_fninit(struct x86_emulate_ctxt *ctxt)
@@ -1071,16 +1072,9 @@ static int em_fnstsw(struct x86_emulate_ctxt *ctxt) 
	return X86EMUL_CONTINUE;

}



static void decode_register_operand(struct x86_emulate_ctxt *ctxt,

				    struct operand *op)

static void __decode_register_operand(struct x86_emulate_ctxt *ctxt,

				      struct operand *op, int reg)

{

	unsigned int reg;



	if (ctxt->d & ModRM)

		reg = ctxt->modrm_reg;

	else

		reg = (ctxt->b & 7) | ((ctxt->rex_prefix & 1) << 3);



	if (ctxt->d & Sse) {

		op->type = OP_XMM;

		op->bytes = 16;
@@ -1099,9 +1093,20 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt, 
	op->type = OP_REG;

	op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes;

	op->addr.reg = decode_register(ctxt, reg, ctxt->d & ByteOp);



	fetch_register_operand(op);

	op->orig_val = op->val;

}



static void decode_register_operand(struct x86_emulate_ctxt *ctxt,

				    struct operand *op)

{

	unsigned int reg;



	if (ctxt->d & ModRM)

		reg = ctxt->modrm_reg;

	else

		reg = (ctxt->b & 7) | ((ctxt->rex_prefix & 1) << 3);



	__decode_register_operand(ctxt, op, reg);

}



static void adjust_modrm_seg(struct x86_emulate_ctxt *ctxt, int base_reg)
@@ -1128,24 +1133,7 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt, 
	ctxt->modrm_seg = VCPU_SREG_DS;



	if (ctxt->modrm_mod == 3 || (ctxt->d & NoMod)) {

		op->type = OP_REG;

		op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes;

		op->addr.reg = decode_register(ctxt, ctxt->modrm_rm,

				ctxt->d & ByteOp);

		if (ctxt->d & Sse) {

			op->type = OP_XMM;

			op->bytes = 16;

			op->addr.xmm = ctxt->modrm_rm;

			kvm_read_sse_reg(ctxt->modrm_rm, &op->vec_val);

			return rc;

		}

		if (ctxt->d & Mmx) {

			op->type = OP_MM;

			op->bytes = 8;

			op->addr.mm = ctxt->modrm_rm & 7;

			return rc;

		}

		fetch_register_operand(op);

		__decode_register_operand(ctxt, op, ctxt->modrm_rm);

		return rc;

	}
@@ -4619,14 +4607,12 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op, 
		op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes;

		op->addr.reg = reg_rmw(ctxt, VCPU_REGS_RAX);

		fetch_register_operand(op);

		op->orig_val = op->val;

		break;

	case OpAccLo:

		op->type = OP_REG;

		op->bytes = (ctxt->d & ByteOp) ? 2 : ctxt->op_bytes;

		op->addr.reg = reg_rmw(ctxt, VCPU_REGS_RAX);

		fetch_register_operand(op);

		op->orig_val = op->val;

		break;

	case OpAccHi:

		if (ctxt->d & ByteOp) {
@@ -4637,7 +4623,6 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op, 
		op->bytes = ctxt->op_bytes;

		op->addr.reg = reg_rmw(ctxt, VCPU_REGS_RDX);

		fetch_register_operand(op);

		op->orig_val = op->val;

		break;

	case OpDI:

		op->type = OP_MEM;