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| author | David Hildenbrand <dahi@linux.vnet.ibm.com> | 2016-02-02 12:26:00 +0100 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2016-06-20 09:54:33 +0200 |
| commit | e52f8b6112353e9e8eac64f082bfbc65e64bb2dd (patch) | |
| tree | c6a4ef5a83a70a8ec09cdbff45316cb1ce1ea956 /arch/s390 | |
| parent | s390/mm: fix races on gmap_shadow creation (diff) | |
| download | linux-e52f8b6112353e9e8eac64f082bfbc65e64bb2dd.tar.xz linux-e52f8b6112353e9e8eac64f082bfbc65e64bb2dd.zip | |
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: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/kvm/gaccess.c | 32 |
1 files changed, 15 insertions, 17 deletions
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c index c5f79c1205cf..5b5eee2d51cd 100644 --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -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) { + if (rc) rc = kvm_s390_shadow_tables(sg, saddr, &pgt, &dat_protection); - if (rc) - return rc; - } vaddr.addr = saddr; - 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) + rc = gmap_read_table(sg->parent, pgt + vaddr.px * 8, &pte.val); + 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; - rc = gmap_shadow_page(sg, saddr, __pte(pte.val)); - if (rc) - return rc; - return 0; + if (!rc && write && dat_protection) + rc = PGM_PROTECTION; + if (!rc) + rc = gmap_shadow_page(sg, saddr, __pte(pte.val)); + up_read(&sg->mm->mmap_sem); + return rc; } |