Messages in this thread | | | Date | Fri, 27 Oct 2023 13:06:57 -0400 | Subject | Re: [PATCH v2 2/3] s390/vfio-ap: set status response code to 06 on gisc registration failure | From | Tony Krowiak <> |
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On 10/27/23 10:03, Halil Pasic wrote: > On Fri, 27 Oct 2023 09:36:26 -0400 > Tony Krowiak <akrowiak@linux.ibm.com> wrote: > >>>> The interception handler for the PQAP(AQIC) command calls the >>>> kvm_s390_gisc_register function to register the guest ISC with the channel >>>> subsystem. If that call fails, the status response code 08 - indicating >>>> Invalid ZONE/GISA designation - is returned to the guest. This response >>>> code does not make sense because the non-zero return code from the >>>> kvm_s390_gisc_register function can be due one of two things: Either the >>>> ISC passed as a parameter by the guest to the PQAP(AQIC) command is greater >>>> than the maximum ISC value allowed, or the guest is not using a GISA. >>> >>> The "ISC passed as a parameter by the guest to the PQAP(AQIC) command is >>> greater than the maximum ISC value allowed" is not possible. The isc is >>> 3 bits wide and all 8 values that can be represented on 3 bits are valid. >>> >>> This is only possible if the hypervisor was to mess up, or if the machine >>> was broken. >> >> kvm_s390_gisc_register(struct kvm *kvm, u32 gisc) >> { >> struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int; >> >> if (!gi->origin) >> return -ENODEV; >> if (gisc > MAX_ISC) >> return -ERANGE; >> ... >> >> Just quoting what is in the code. > > Right! But it is not the guest that calls this function directly. This > function is called by the vfio_ap code. > > The guest passes ISC in bits 61, 62 and 63 of GR1. > > So the guest can't give you an invalid value.
Yes, I got it the first time you said that.
> > Regards, > Halil
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