read_id_reg
p->regval = read_id_reg(vcpu, r);
p->regval = read_id_reg(vcpu, r);
*val = read_id_reg(vcpu, rd);
*val = read_id_reg(vcpu, rd);
if (val != read_id_reg(vcpu, rd))
expected = read_id_reg(vcpu, r);