static int handle_sske()

in kvm/priv.c [342:426]

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

static int handle_sske(struct kvm_vcpu *vcpu)
{
	unsigned char m3 = vcpu->arch.sie_block->ipb >> 28;
	unsigned long start, end;
	unsigned char key, oldkey;
	int reg1, reg2;
	bool unlocked;
	int rc;

	vcpu->stat.instruction_sske++;

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

	rc = try_handle_skey(vcpu);
	if (rc)
		return rc != -EAGAIN ? rc : 0;

	if (!test_kvm_facility(vcpu->kvm, 8))
		m3 &= ~SSKE_MB;
	if (!test_kvm_facility(vcpu->kvm, 10))
		m3 &= ~(SSKE_MC | SSKE_MR);
	if (!test_kvm_facility(vcpu->kvm, 14))
		m3 &= ~SSKE_NQ;

	kvm_s390_get_regs_rre(vcpu, &reg1, &reg2);

	key = vcpu->run->s.regs.gprs[reg1] & 0xfe;
	start = vcpu->run->s.regs.gprs[reg2] & PAGE_MASK;
	start = kvm_s390_logical_to_effective(vcpu, start);
	if (m3 & SSKE_MB) {
		/* start already designates an absolute address */
		end = (start + _SEGMENT_SIZE) & ~(_SEGMENT_SIZE - 1);
	} else {
		start = kvm_s390_real_to_abs(vcpu, start);
		end = start + PAGE_SIZE;
	}

	while (start != end) {
		unsigned long vmaddr = gfn_to_hva(vcpu->kvm, gpa_to_gfn(start));
		unlocked = false;

		if (kvm_is_error_hva(vmaddr))
			return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);

		mmap_read_lock(current->mm);
		rc = cond_set_guest_storage_key(current->mm, vmaddr, key, &oldkey,
						m3 & SSKE_NQ, m3 & SSKE_MR,
						m3 & SSKE_MC);

		if (rc < 0) {
			rc = fixup_user_fault(current->mm, vmaddr,
					      FAULT_FLAG_WRITE, &unlocked);
			rc = !rc ? -EAGAIN : rc;
		}
		mmap_read_unlock(current->mm);
		if (rc == -EFAULT)
			return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
		if (rc == -EAGAIN)
			continue;
		if (rc < 0)
			return rc;
		start += PAGE_SIZE;
	}

	if (m3 & (SSKE_MC | SSKE_MR)) {
		if (m3 & SSKE_MB) {
			/* skey in reg1 is unpredictable */
			kvm_s390_set_psw_cc(vcpu, 3);
		} else {
			kvm_s390_set_psw_cc(vcpu, rc);
			vcpu->run->s.regs.gprs[reg1] &= ~0xff00UL;
			vcpu->run->s.regs.gprs[reg1] |= (u64) oldkey << 8;
		}
	}
	if (m3 & SSKE_MB) {
		if (psw_bits(vcpu->arch.sie_block->gpsw).eaba == PSW_BITS_AMODE_64BIT)
			vcpu->run->s.regs.gprs[reg2] &= ~PAGE_MASK;
		else
			vcpu->run->s.regs.gprs[reg2] &= ~0xfffff000UL;
		end = kvm_s390_logical_to_effective(vcpu, end);
		vcpu->run->s.regs.gprs[reg2] |= end;
	}
	return 0;
}