kernel_optimize_test/arch/s390/mm
Martin Schwidefsky 4be130a084 s390/mm: add shadow gmap support
For a nested KVM guest the outer KVM host needs to create shadow
page tables for the nested guest. This patch adds the basic support
to the guest address space (gmap) code.

For each guest address space the inner KVM host creates, the first
outer KVM host needs to create shadow page tables. The address space
is identified by the ASCE loaded into the control register 1 at the
time the inner SIE instruction for the second nested KVM guest is
executed. The outer KVM host creates the shadow tables starting with
the table identified by the ASCE on a on-demand basis. The outer KVM
host will get repeated faults for all the shadow tables needed to
run the second KVM guest.

While a shadow page table for the second KVM guest is active the access
to the origin region, segment and page tables needs to be restricted
for the first KVM guest. For region and segment and page tables the first
KVM guest may read the memory, but write attempt has to lead to an
unshadow.  This is done using the page invalid and read-only bits in the
page table of the first KVM guest. If the first guest re-accesses one of
the origin pages of a shadow, it gets a fault and the affected parts of
the shadow page table hierarchy needs to be removed again.

PGSTE tables don't have to be shadowed, as all interpretation assist can't
deal with the invalid bits in the shadow pte being set differently than
the original ones provided by the first KVM guest.

Many bug fixes and improvements by David Hildenbrand.

Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2016-06-20 09:54:04 +02:00
..
cmm.c
dump_pagetables.c
extmem.c s390: Use pr_warn instead of pr_warning 2016-03-07 13:12:04 +01:00
fault.c s390/mm: add shadow gmap support 2016-06-20 09:54:04 +02:00
gmap.c s390/mm: add shadow gmap support 2016-06-20 09:54:04 +02:00
gup.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2016-04-01 07:15:54 -05:00
hugetlbpage.c s390/mm: uninline pmdp_xxx functions from pgtable.h 2016-03-08 15:00:14 +01:00
init.c s390/mm: fix asce_bits handling with dynamic pagetable levels 2016-04-21 09:50:09 +02:00
maccess.c s390/maccess: reduce stnsm instructions 2016-02-17 09:05:04 +01:00
Makefile s390/extable: use generic search and sort routines 2016-03-22 15:36:02 -07:00
mem_detect.c s390/mem_detect: use unsigned longs 2016-01-11 12:27:11 +01:00
mmap.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2016-05-18 12:17:16 -07:00
page-states.c
pageattr.c s390/pageattr: do a single TLB flush for change_page_attr 2016-02-23 08:56:17 +01:00
pgalloc.c s390/mm: add shadow gmap support 2016-06-20 09:54:04 +02:00
pgtable.c s390/mm: add shadow gmap support 2016-06-20 09:54:04 +02:00
vmem.c s390/vmem: remove unused function parameter 2016-05-11 10:20:32 +02:00