Messages in this thread | | | Subject | Re: [PATCH v3 2/9] s390: ap: kvm: setting a hook for PQAP instructions | From | Pierre Morel <> | Date | Tue, 19 Feb 2019 20:50:58 +0100 |
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On 18/02/2019 23:42, Cornelia Huck wrote: > On Mon, 18 Feb 2019 19:29:10 +0100 > Pierre Morel <pmorel@linux.ibm.com> wrote: > >> On 15/02/2019 23:02, Tony Krowiak wrote: >>> On 2/14/19 8:51 AM, Pierre Morel wrote: > >>>> +/* >>>> + * handle_pqap: Handling pqap interception >>>> + * @vcpu: the vcpu having issue the pqap instruction >>>> + * >>>> + * This callback only handles PQAP/AQIC instruction and >>>> + * calls a dedicated callback for this instruction if >>>> + * a driver did register one in the CRYPTO satellite of the >>>> + * SIE block. >>>> + * >>>> + * Do not change the behavior if, return -EOPNOTSUPP if: >>>> + * - the hook is not used do not change the behavior. >>>> + * - AP instructions are not available or not available to the guest >>>> + * - the instruction is not PQAP with function code indicating >>>> + * AQIC do not change the previous behavior. >>>> + * >>>> + * For PQAP/AQIC instruction, verify privilege and specifications >>>> + * >>>> + * return the value returned by the callback. >>>> + */ >>>> +static int handle_pqap(struct kvm_vcpu *vcpu) >>>> +{ >>>> + uint8_t fc; >>>> + >>>> + /* Verify that the hook callback is registered */ >>>> + if (!vcpu->kvm->arch.crypto.pqap_hook) >>>> + return -EOPNOTSUPP; >>>> + /* Verify that the AP instruction are available */ >>>> + if (!ap_instructions_available()) >>>> + return -EOPNOTSUPP; >>>> + /* Verify that the guest is allowed to use AP instructions */ >>>> + if (!(vcpu->arch.sie_block->eca & ECA_APIE)) >>>> + return -EOPNOTSUPP; >>>> + /* Verify that the function code is AQIC */ >>>> + fc = vcpu->run->s.regs.gprs[0] >> 24; >>>> + if (fc != 0x03) >>>> + return -EOPNOTSUPP; >>> >>> This does not belong here. Function code 3 is one of 7 function codes >>> that can be sent with the PQAP instruction. This belongs in the PQAP >>> hook code. >> >> On one hand, effectively I would prefer to put the code in the VFIO >> driver code. >> On the other hand, doing this would lead to export the code for >> test_kvm_facility() and kvm_s390_inject_program_int() from the kvm-s390.h >> >> I choose not to export these functions from the KVM code. >> >> Would like opinion from KVM maintainers? > > Looking at this (and without access to the specification...), I think > the check for problem state makes sense in here (if this applies to all > PQAP functions equally, which seems likely). The check for the facility > makes more sense in the handler. You can probably still inject the > specification exception here if you use a clever return code. >
If there is no objection on exporting the KVM functions... I can do this.
> Another option: Provide a way to register a callback per function code; > this allows you to still do the check here and extend it later for > other function codes (which will probably be indicated by another > facility).
I like this option even better.
Regards, Pierre
-- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany
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