static int kvm_s390_shadow_tables()

in kvm/gaccess.c [1022:1197]

• 169 lines of code
• 56 McCabe index (conditional complexity)

static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr,
				  unsigned long *pgt, int *dat_protection,
				  int *fake)
{
	struct gmap *parent;
	union asce asce;
	union vaddress vaddr;
	unsigned long ptr;
	int rc;

	*fake = 0;
	*dat_protection = 0;
	parent = sg->parent;
	vaddr.addr = saddr;
	asce.val = sg->orig_asce;
	ptr = asce.origin * PAGE_SIZE;
	if (asce.r) {
		*fake = 1;
		ptr = 0;
		asce.dt = ASCE_TYPE_REGION1;
	}
	switch (asce.dt) {
	case ASCE_TYPE_REGION1:
		if (vaddr.rfx01 > asce.tl && !*fake)
			return PGM_REGION_FIRST_TRANS;
		break;
	case ASCE_TYPE_REGION2:
		if (vaddr.rfx)
			return PGM_ASCE_TYPE;
		if (vaddr.rsx01 > asce.tl)
			return PGM_REGION_SECOND_TRANS;
		break;
	case ASCE_TYPE_REGION3:
		if (vaddr.rfx || vaddr.rsx)
			return PGM_ASCE_TYPE;
		if (vaddr.rtx01 > asce.tl)
			return PGM_REGION_THIRD_TRANS;
		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;
		break;
	}

	switch (asce.dt) {
	case ASCE_TYPE_REGION1: {
		union region1_table_entry rfte;

		if (*fake) {
			ptr += vaddr.rfx * _REGION1_SIZE;
			rfte.val = ptr;
			goto shadow_r2t;
		}
		*pgt = ptr + vaddr.rfx * 8;
		rc = gmap_read_table(parent, ptr + vaddr.rfx * 8, &rfte.val);
		if (rc)
			return rc;
		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 (sg->edat_level >= 1)
			*dat_protection |= rfte.p;
		ptr = rfte.rto * PAGE_SIZE;
shadow_r2t:
		rc = gmap_shadow_r2t(sg, saddr, rfte.val, *fake);
		if (rc)
			return rc;
	}
		fallthrough;
	case ASCE_TYPE_REGION2: {
		union region2_table_entry rste;

		if (*fake) {
			ptr += vaddr.rsx * _REGION2_SIZE;
			rste.val = ptr;
			goto shadow_r3t;
		}
		*pgt = ptr + vaddr.rsx * 8;
		rc = gmap_read_table(parent, ptr + vaddr.rsx * 8, &rste.val);
		if (rc)
			return rc;
		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 (sg->edat_level >= 1)
			*dat_protection |= rste.p;
		ptr = rste.rto * PAGE_SIZE;
shadow_r3t:
		rste.p |= *dat_protection;
		rc = gmap_shadow_r3t(sg, saddr, rste.val, *fake);
		if (rc)
			return rc;
	}
		fallthrough;
	case ASCE_TYPE_REGION3: {
		union region3_table_entry rtte;

		if (*fake) {
			ptr += vaddr.rtx * _REGION3_SIZE;
			rtte.val = ptr;
			goto shadow_sgt;
		}
		*pgt = ptr + vaddr.rtx * 8;
		rc = gmap_read_table(parent, ptr + vaddr.rtx * 8, &rtte.val);
		if (rc)
			return rc;
		if (rtte.i)
			return PGM_REGION_THIRD_TRANS;
		if (rtte.tt != TABLE_TYPE_REGION3)
			return PGM_TRANSLATION_SPEC;
		if (rtte.cr && asce.p && sg->edat_level >= 2)
			return PGM_TRANSLATION_SPEC;
		if (rtte.fc && sg->edat_level >= 2) {
			*dat_protection |= rtte.fc0.p;
			*fake = 1;
			ptr = rtte.fc1.rfaa * _REGION3_SIZE;
			rtte.val = ptr;
			goto shadow_sgt;
		}
		if (vaddr.sx01 < rtte.fc0.tf || vaddr.sx01 > rtte.fc0.tl)
			return PGM_SEGMENT_TRANSLATION;
		if (sg->edat_level >= 1)
			*dat_protection |= rtte.fc0.p;
		ptr = rtte.fc0.sto * PAGE_SIZE;
shadow_sgt:
		rtte.fc0.p |= *dat_protection;
		rc = gmap_shadow_sgt(sg, saddr, rtte.val, *fake);
		if (rc)
			return rc;
	}
		fallthrough;
	case ASCE_TYPE_SEGMENT: {
		union segment_table_entry ste;

		if (*fake) {
			ptr += vaddr.sx * _SEGMENT_SIZE;
			ste.val = ptr;
			goto shadow_pgt;
		}
		*pgt = ptr + vaddr.sx * 8;
		rc = gmap_read_table(parent, ptr + vaddr.sx * 8, &ste.val);
		if (rc)
			return rc;
		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;
		*dat_protection |= ste.fc0.p;
		if (ste.fc && sg->edat_level >= 1) {
			*fake = 1;
			ptr = ste.fc1.sfaa * _SEGMENT_SIZE;
			ste.val = ptr;
			goto shadow_pgt;
		}
		ptr = ste.fc0.pto * (PAGE_SIZE / 2);
shadow_pgt:
		ste.fc0.p |= *dat_protection;
		rc = gmap_shadow_pgt(sg, saddr, ste.val, *fake);
		if (rc)
			return rc;
	}
	}
	/* Return the parent address of the page table */
	*pgt = ptr;
	return 0;
}