static unsigned long guest_translate()

in kvm/gaccess.c [614:776]

• 158 lines of code
• 65 McCabe index (conditional complexity)

static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
				     unsigned long *gpa, const union asce asce,
				     enum gacc_mode mode, enum prot_type *prot)
{
	union vaddress vaddr = {.addr = gva};
	union raddress raddr = {.addr = gva};
	union page_table_entry pte;
	int dat_protection = 0;
	int iep_protection = 0;
	union ctlreg0 ctlreg0;
	unsigned long ptr;
	int edat1, edat2, iep;

	ctlreg0.val = vcpu->arch.sie_block->gcr[0];
	edat1 = ctlreg0.edat && test_kvm_facility(vcpu->kvm, 8);
	edat2 = edat1 && test_kvm_facility(vcpu->kvm, 78);
	iep = ctlreg0.iep && test_kvm_facility(vcpu->kvm, 130);
	if (asce.r)
		goto real_address;
	ptr = asce.origin * PAGE_SIZE;
	switch (asce.dt) {
	case ASCE_TYPE_REGION1:
		if (vaddr.rfx01 > asce.tl)
			return PGM_REGION_FIRST_TRANS;
		ptr += vaddr.rfx * 8;
		break;
	case ASCE_TYPE_REGION2:
		if (vaddr.rfx)
			return PGM_ASCE_TYPE;
		if (vaddr.rsx01 > asce.tl)
			return PGM_REGION_SECOND_TRANS;
		ptr += vaddr.rsx * 8;
		break;
	case ASCE_TYPE_REGION3:
		if (vaddr.rfx || vaddr.rsx)
			return PGM_ASCE_TYPE;
		if (vaddr.rtx01 > asce.tl)
			return PGM_REGION_THIRD_TRANS;
		ptr += vaddr.rtx * 8;
		break;
	case ASCE_TYPE_SEGMENT:
		if (vaddr.rfx || vaddr.rsx || vaddr.rtx)
			return PGM_ASCE_TYPE;
		if (vaddr.sx01 > asce.tl)
			return PGM_SEGMENT_TRANSLATION;
		ptr += vaddr.sx * 8;
		break;
	}
	switch (asce.dt) {
	case ASCE_TYPE_REGION1:	{
		union region1_table_entry rfte;

		if (kvm_is_error_gpa(vcpu->kvm, ptr))
			return PGM_ADDRESSING;
		if (deref_table(vcpu->kvm, ptr, &rfte.val))
			return -EFAULT;
		if (rfte.i)
			return PGM_REGION_FIRST_TRANS;
		if (rfte.tt != TABLE_TYPE_REGION1)
			return PGM_TRANSLATION_SPEC;
		if (vaddr.rsx01 < rfte.tf || vaddr.rsx01 > rfte.tl)
			return PGM_REGION_SECOND_TRANS;
		if (edat1)
			dat_protection |= rfte.p;
		ptr = rfte.rto * PAGE_SIZE + vaddr.rsx * 8;
	}
		fallthrough;
	case ASCE_TYPE_REGION2: {
		union region2_table_entry rste;

		if (kvm_is_error_gpa(vcpu->kvm, ptr))
			return PGM_ADDRESSING;
		if (deref_table(vcpu->kvm, ptr, &rste.val))
			return -EFAULT;
		if (rste.i)
			return PGM_REGION_SECOND_TRANS;
		if (rste.tt != TABLE_TYPE_REGION2)
			return PGM_TRANSLATION_SPEC;
		if (vaddr.rtx01 < rste.tf || vaddr.rtx01 > rste.tl)
			return PGM_REGION_THIRD_TRANS;
		if (edat1)
			dat_protection |= rste.p;
		ptr = rste.rto * PAGE_SIZE + vaddr.rtx * 8;
	}
		fallthrough;
	case ASCE_TYPE_REGION3: {
		union region3_table_entry rtte;

		if (kvm_is_error_gpa(vcpu->kvm, ptr))
			return PGM_ADDRESSING;
		if (deref_table(vcpu->kvm, ptr, &rtte.val))
			return -EFAULT;
		if (rtte.i)
			return PGM_REGION_THIRD_TRANS;
		if (rtte.tt != TABLE_TYPE_REGION3)
			return PGM_TRANSLATION_SPEC;
		if (rtte.cr && asce.p && edat2)
			return PGM_TRANSLATION_SPEC;
		if (rtte.fc && edat2) {
			dat_protection |= rtte.fc1.p;
			iep_protection = rtte.fc1.iep;
			raddr.rfaa = rtte.fc1.rfaa;
			goto absolute_address;
		}
		if (vaddr.sx01 < rtte.fc0.tf)
			return PGM_SEGMENT_TRANSLATION;
		if (vaddr.sx01 > rtte.fc0.tl)
			return PGM_SEGMENT_TRANSLATION;
		if (edat1)
			dat_protection |= rtte.fc0.p;
		ptr = rtte.fc0.sto * PAGE_SIZE + vaddr.sx * 8;
	}
		fallthrough;
	case ASCE_TYPE_SEGMENT: {
		union segment_table_entry ste;

		if (kvm_is_error_gpa(vcpu->kvm, ptr))
			return PGM_ADDRESSING;
		if (deref_table(vcpu->kvm, ptr, &ste.val))
			return -EFAULT;
		if (ste.i)
			return PGM_SEGMENT_TRANSLATION;
		if (ste.tt != TABLE_TYPE_SEGMENT)
			return PGM_TRANSLATION_SPEC;
		if (ste.cs && asce.p)
			return PGM_TRANSLATION_SPEC;
		if (ste.fc && edat1) {
			dat_protection |= ste.fc1.p;
			iep_protection = ste.fc1.iep;
			raddr.sfaa = ste.fc1.sfaa;
			goto absolute_address;
		}
		dat_protection |= ste.fc0.p;
		ptr = ste.fc0.pto * (PAGE_SIZE / 2) + vaddr.px * 8;
	}
	}
	if (kvm_is_error_gpa(vcpu->kvm, ptr))
		return PGM_ADDRESSING;
	if (deref_table(vcpu->kvm, ptr, &pte.val))
		return -EFAULT;
	if (pte.i)
		return PGM_PAGE_TRANSLATION;
	if (pte.z)
		return PGM_TRANSLATION_SPEC;
	dat_protection |= pte.p;
	iep_protection = pte.iep;
	raddr.pfra = pte.pfra;
real_address:
	raddr.addr = kvm_s390_real_to_abs(vcpu, raddr.addr);
absolute_address:
	if (mode == GACC_STORE && dat_protection) {
		*prot = PROT_TYPE_DAT;
		return PGM_PROTECTION;
	}
	if (mode == GACC_IFETCH && iep_protection && iep) {
		*prot = PROT_TYPE_IEP;
		return PGM_PROTECTION;
	}
	if (kvm_is_error_gpa(vcpu->kvm, raddr.addr))
		return PGM_ADDRESSING;
	*gpa = raddr.addr;
	return 0;
}