Messages in this thread | | | Subject | Re: [PATCH] KVM: s390: Enable specification exception interpretation | From | Christian Borntraeger <> | Date | Wed, 7 Jul 2021 10:59:29 +0200 |
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On 07.07.21 10:56, Janis Schoetterl-Glausch wrote: > On 7/7/21 10:30 AM, Christian Borntraeger wrote: >> >> >> On 06.07.21 13:47, Janis Schoetterl-Glausch wrote: >>> 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. >> >> I think I will add >> >> 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. > > Might also mention vSIE and/or incorporate into first paragraph: > > When this feature is enabled the hardware is free to interpret > specification exceptions generated by the guest, instead of causing > program interruption interceptions, but it is not required to. > There is no indication if this feature is available or not, > so we can simply set this bit and if the hardware ignores it > we fall back to intercept 8 handling. > The same applies to vSIE, we forward the guest hypervisor's bit > and fall back to injection if interpretation does not occur.
Can you maybe resend a v2 with all comments (and RBs) added?
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