linux_dsm_epyc7002/arch/s390
Michael Mueller cc674ef252 KVM: s390: introduce module parameter kvm.use_gisa
The boolean module parameter "kvm.use_gisa" controls if newly
created guests will use the GISA facility if provided by the
host system. The default is yes.

  # cat /sys/module/kvm/parameters/use_gisa
  Y

The parameter can be changed on the fly.

  # echo N > /sys/module/kvm/parameters/use_gisa

Already running guests are not affected by this change.

The kvm s390 debug feature shows if a guest is running with GISA.

  # grep gisa /sys/kernel/debug/s390dbf/kvm-$pid/sprintf
  00 01582725059:843303 3 - 08 00000000e119bc01  gisa 0x00000000c9ac2642 initialized
  00 01582725059:903840 3 - 11 000000004391ee22  00[0000000000000000-0000000000000000]: AIV gisa format-1 enabled for cpu 000
  ...
  00 01582725059:916847 3 - 08 0000000094fff572  gisa 0x00000000c9ac2642 cleared

In general, that value should not be changed as the GISA facility
enhances interruption delivery performance.

A reason to switch the GISA facility off might be a performance
comparison run or debugging.

Signed-off-by: Michael Mueller <mimu@linux.ibm.com>
Link: https://lore.kernel.org/r/20200227091031.102993-1-mimu@linux.ibm.com
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2020-02-27 19:47:13 +01:00
..
appldata proc/sysctl: add shared variables for range check 2019-07-18 17:08:07 -07:00
boot s390/protvirt: introduce host side setup 2020-02-27 19:44:40 +01:00
configs locking/refcount: Consolidate implementations of refcount_t 2019-11-25 09:15:32 +01:00
crypto s390/pkey/zcrypt: Support EP11 AES secure keys 2020-01-30 13:07:56 +01:00
hypfs fs_parse: fold fs_parameter_desc/fs_parameter_spec 2020-02-07 14:48:37 -05:00
include KVM: s390: protvirt: Add UV cpu reset calls 2020-02-27 19:47:12 +01:00
kernel s390/protvirt: Add sysfs firmware interface for Ultravisor information 2020-02-27 19:44:40 +01:00
kvm KVM: s390: introduce module parameter kvm.use_gisa 2020-02-27 19:47:13 +01:00
lib s390/test_unwind: fix spelling mistake "reqister" -> "register" 2019-12-11 19:53:23 +01:00
mm KVM: s390/mm: Make pages accessible before destroying the guest 2020-02-27 19:47:11 +01:00
net s390/bpf: Remove JITed image size limitations 2019-11-18 19:51:16 -08:00
numa s390/numa: correct early_param handling 2019-08-26 12:51:17 +02:00
oprofile s390/unwind: introduce stack unwind API 2019-05-02 13:54:11 +02:00
pci s390/pci: Fix possible deadlock in recover_store() 2020-01-22 13:05:34 +01:00
purgatory s390/purgatory: do not build purgatory with kcov, kasan and friends 2019-12-18 23:29:26 +01:00
scripts s390/build: use size command to perform empty .bss check 2019-08-08 14:36:53 +02:00
tools kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kbuild
Kconfig s390 updates for the 5.6 merge window #2 2020-02-05 17:33:35 +00:00
Kconfig.debug
Makefile s390: adjust -mpacked-stack support check for clang 10 2020-01-22 13:05:35 +01:00