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| author | Christian Borntraeger | 2017-08-23 12:16:23 +0200 |
|---|---|---|
| committer | Cornelia Huck | 2017-08-30 18:23:25 +0200 |
| commit | e9a3591fa09f273592451f8b9f83692bcbedb60c (patch) | |
| tree | eef44d1506b76ce330950ca18b3139eed65471c5 /hw | |
| parent | s390x: wire up diag288 in tcg (diff) | |
| download | qemu-e9a3591fa09f273592451f8b9f83692bcbedb60c.tar.gz qemu-e9a3591fa09f273592451f8b9f83692bcbedb60c.tar.xz qemu-e9a3591fa09f273592451f8b9f83692bcbedb60c.zip | |
configure: enable --s390-pgste linker option
KVM guests on s390 need a different page table layout than normal
processes (2kb page table + 2kb page status extensions vs 2kb page table
only). As of today this has to be enabled via the vm.allocate_pgste
sysctl.
Newer kernels (>= 4.12) on s390 check for an S390_PGSTE program header
and enable the pgste page table extensions in that case. This makes the
vm.allocate_pgste sysctl unnecessary. We enable this program header for
the s390 system emulation (qemu-system-s390x) if we build on s390
- for s390 system emulation
- the linker supports --s390-pgste (binutils >= 2.29)
- KVM is enabled
This will allow distributions to disable the global vm.allocate_pgste
sysctl, which will improve the page table allocation for non KVM
processes as only 2kb chunks are necessary.
Cc: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Dan Horak <dhorak@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1503483383-199649-1-git-send-email-borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Diffstat (limited to 'hw')
0 files changed, 0 insertions, 0 deletions