static int handle_stsi()

in kvm/priv.c [848:927]

• 72 lines of code
• 19 McCabe index (conditional complexity)

static int handle_stsi(struct kvm_vcpu *vcpu)
{
	int fc = (vcpu->run->s.regs.gprs[0] & 0xf0000000) >> 28;
	int sel1 = vcpu->run->s.regs.gprs[0] & 0xff;
	int sel2 = vcpu->run->s.regs.gprs[1] & 0xffff;
	unsigned long mem = 0;
	u64 operand2;
	int rc = 0;
	u8 ar;

	vcpu->stat.instruction_stsi++;
	VCPU_EVENT(vcpu, 3, "STSI: fc: %u sel1: %u sel2: %u", fc, sel1, sel2);

	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
		return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);

	if (fc > 3) {
		kvm_s390_set_psw_cc(vcpu, 3);
		return 0;
	}

	if (vcpu->run->s.regs.gprs[0] & 0x0fffff00
	    || vcpu->run->s.regs.gprs[1] & 0xffff0000)
		return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);

	if (fc == 0) {
		vcpu->run->s.regs.gprs[0] = 3 << 28;
		kvm_s390_set_psw_cc(vcpu, 0);
		return 0;
	}

	operand2 = kvm_s390_get_base_disp_s(vcpu, &ar);

	if (!kvm_s390_pv_cpu_is_protected(vcpu) && (operand2 & 0xfff))
		return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);

	switch (fc) {
	case 1: /* same handling for 1 and 2 */
	case 2:
		mem = get_zeroed_page(GFP_KERNEL_ACCOUNT);
		if (!mem)
			goto out_no_data;
		if (stsi((void *) mem, fc, sel1, sel2))
			goto out_no_data;
		break;
	case 3:
		if (sel1 != 2 || sel2 != 2)
			goto out_no_data;
		mem = get_zeroed_page(GFP_KERNEL_ACCOUNT);
		if (!mem)
			goto out_no_data;
		handle_stsi_3_2_2(vcpu, (void *) mem);
		break;
	}
	if (kvm_s390_pv_cpu_is_protected(vcpu)) {
		memcpy((void *)sida_origin(vcpu->arch.sie_block), (void *)mem,
		       PAGE_SIZE);
		rc = 0;
	} else {
		rc = write_guest(vcpu, operand2, ar, (void *)mem, PAGE_SIZE);
	}
	if (rc) {
		rc = kvm_s390_inject_prog_cond(vcpu, rc);
		goto out;
	}
	if (vcpu->kvm->arch.user_stsi) {
		insert_stsi_usr_data(vcpu, operand2, ar, fc, sel1, sel2);
		rc = -EREMOTE;
	}
	trace_kvm_s390_handle_stsi(vcpu, fc, sel1, sel2, operand2);
	free_page(mem);
	kvm_s390_set_psw_cc(vcpu, 0);
	vcpu->run->s.regs.gprs[0] = 0;
	return rc;
out_no_data:
	kvm_s390_set_psw_cc(vcpu, 3);
out:
	free_page(mem);
	return rc;
}