diff options
| author | Janis Schoetterl-Glausch <scgl@linux.ibm.com> | 2021-06-29 10:55:30 +0200 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2021-08-27 18:35:20 +0200 |
| commit | 7119decf47d9867266459615be502e5d2cecedba (patch) | |
| tree | af9d76e4525e2be6fdf33853336a7bfe32e6a4e7 /arch/s390/kvm/vsie.c | |
| parent | 1f703d2cf20464338c3d5279dddfb65ac79b8782 (diff) | |
KVM: s390: Enable specification exception interpretation
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>
Diffstat (limited to 'arch/s390/kvm/vsie.c')
| -rw-r--r-- | arch/s390/kvm/vsie.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c index 4002a24bc43a..acda4b6fc851 100644 --- a/arch/s390/kvm/vsie.c +++ b/arch/s390/kvm/vsie.c @@ -510,6 +510,8 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) prefix_unmapped(vsie_page); scb_s->ecb |= ECB_TE; } + /* specification exception interpretation */ + scb_s->ecb |= scb_o->ecb & ECB_SPECI; /* branch prediction */ if (test_kvm_facility(vcpu->kvm, 82)) scb_s->fpf |= scb_o->fpf & FPF_BPBC; |