KVM: s390: Enable specification exception interpretation

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When this feature is enabled the hardware is free to interpret
specification exceptions generated by the guest, instead of causing
program interruption interceptions.

This benefits (test) programs that generate a lot of specification
exceptions (roughly 4x increase in exceptions/sec).

Interceptions will occur as before if ICTL_PINT is set,
i.e. if guest debug is enabled.

There is no indication if this feature is available or not and the
hardware is free to interpret or not. So we can simply set this bit and
if the hardware ignores it we fall back to intercept 8 handling.

Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Link: https://lore.kernel.org/linux-s390/20210706114714.3936825-1-scgl@linux.ibm.com/
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

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Janis Schoetterl-Glausch 2021-06-29 10:55:30 +02:00 • committed by Christian Borntraeger

parent 1f703d2cf2

commit 7119decf47

3 changed files with 5 additions and 0 deletions

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1

arch/s390/include/asm/kvm_host.h

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arch/s390/kvm/kvm-s390.c

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arch/s390/kvm/vsie.c

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