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Commit e52f8b61 authored by David Hildenbrand's avatar David Hildenbrand Committed by Christian Borntraeger
Browse files

s390/mm: take the mmap_sem in kvm_s390_shadow_fault() 



Instead of doing it in the caller, let's just take the mmap_sem
in kvm_s390_shadow_fault(). By taking it as read, we allow parallel
faulting on shadow page tables, gmap shadow code is prepared for that.

Acked-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 0f7f8489

arch/s390/kvm/gaccess.c

+15 −17
Original line number Diff line number Diff line
@@ -1091,26 +1091,24 @@ int kvm_s390_shadow_fault(struct gmap *sg, unsigned long saddr, int write) 
	int dat_protection;

	int rc;



	down_read(&sg->mm->mmap_sem);



	rc = gmap_shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection);

	if (rc) {

		rc = kvm_s390_shadow_tables(sg, saddr, &pgt, &dat_protection);

	if (rc)

			return rc;

	}

		rc = kvm_s390_shadow_tables(sg, saddr, &pgt, &dat_protection);



	vaddr.addr = saddr;

	if (!rc)

		rc = gmap_read_table(sg->parent, pgt + vaddr.px * 8, &pte.val);

	if (rc)

		return rc;

	if (pte.i)

		return PGM_PAGE_TRANSLATION;

	if (pte.z || pte.co)

		return PGM_TRANSLATION_SPEC;

	if (!rc && pte.i)

		rc = PGM_PAGE_TRANSLATION;

	if (!rc && (pte.z || pte.co))

		rc = PGM_TRANSLATION_SPEC;

	dat_protection |= pte.p;

	if (write && dat_protection)

		return PGM_PROTECTION;

	if (!rc && write && dat_protection)

		rc = PGM_PROTECTION;

	if (!rc)

		rc = gmap_shadow_page(sg, saddr, __pte(pte.val));

	if (rc)

	up_read(&sg->mm->mmap_sem);

	return rc;

	return 0;

}