In some cases (i.e. under extreme memory pressure on the host),
attempting to shadow memory will result in the same memory being
unshadowed, causing a loop.
Add a PGSTE bit to distinguish between shadowed memory and shadowed DAT
tables, fix the unshadowing logic in _gmap_ptep_xchg() to prevent
unnecessary unshadowing and perform better checks.
Also fix the unshadowing logic in _gmap_crstep_xchg_atomic() which did
not unshadow properly when the large page would become unprotected.
Opportunistically add a check in gmap_protect_rmap() to make sure it
won't be called with level == TABLE_TYPE_PAGE_TABLE.
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Fixes: a2c17f9270 ("KVM: s390: New gmap code")
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Add _{SEGMENT,REGION3}_FR_MASK, similar to _{SEGMENT,REGION3}_MASK, but
working on gfn/pfn instead of addresses. Use them in gaccess.c instead
of using the normal masks plus gpa_to_gfn().
Also add _PAGES_PER_{SEGMENT,REGION3} to make future code more readable.
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Introduce a new special softbit for large pages, like already presend
for normal pages, and use it to mark guest mappings that do not have
struct pages.
Whenever a leaf DAT entry becomes dirty, check the special softbit and
only call SetPageDirty() if there is an actual struct page.
Move the logic to mark pages dirty inside _gmap_ptep_xchg() and
_gmap_crstep_xchg_atomic(), to avoid needlessly duplicating the code.
Fixes: 5a74e3d934 ("KVM: s390: KVM-specific bitfields and helper functions")
Fixes: a2c17f9270 ("KVM: s390: New gmap code")
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
The slow path of the fault handler ultimately called gmap_link(), which
assumed the fault was a major fault, and blindly called dat_link().
In case of minor faults, things were not always handled properly; in
particular the prefix and vsie marker bits were ignored.
Move dat_link() into gmap.c, renaming it accordingly. Once moved, the
new _gmap_link() function will be able to correctly honour the prefix
and vsie markers.
This will cause spurious unshadows in some uncommon cases.
Fixes: 94fd9b16cc ("KVM: s390: KVM page table management functions: lifecycle management")
Fixes: a2c17f9270 ("KVM: s390: New gmap code")
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
In practice dat_crstep_xchg() is racy and hard to use correctly. Simply
remove it and replace its uses with dat_crstep_xchg_atomic().
This solves some actual races that lead to system hangs / crashes.
Opportunistically fix an alignment issue in _gmap_crstep_xchg_atomic().
Fixes: 589071eaaa ("KVM: s390: KVM page table management functions: clear and replace")
Fixes: 94fd9b16cc ("KVM: s390: KVM page table management functions: lifecycle management")
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
Remove the PGSTE config option.
Remove all code from linux/s390 mm that involves PGSTEs.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Add page table management functions to be used for KVM guest (gmap)
page tables.
This patch adds functions to handle CMMA and the ESSA instruction.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Add page table management functions to be used for KVM guest (gmap)
page tables.
This patch adds functions to handle memslot creation and destruction,
additional per-pagetable data stored in the PGSTEs, mapping physical
addresses into the gmap, and marking address ranges as prefix.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Add page table management functions to be used for KVM guest (gmap)
page tables.
This patch adds functions related to storage key handling.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Add page table management functions to be used for KVM guest (gmap)
page tables.
This patch adds functions to walk to specific table entries, or to
perform actions on a range of entries.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Add page table management functions to be used for KVM guest (gmap)
page tables.
This patch adds functions to clear, replace or exchange DAT table
entries.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Add page table management functions to be used for KVM guest (gmap)
page tables.
This patch adds the boilerplate and functions for the allocation and
deallocation of DAT tables.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Add KVM-s390 specific bitfields and helper functions to manipulate DAT
tables.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
