On 8/23/18 2:03 PM, David Hildenbrand wrote: > On 23.08.2018 13:53, Janosch Frank wrote: >> On 8/23/18 1:47 PM, Pierre Morel wrote: >>> On 23/08/2018 13:33, Janosch Frank wrote: >>>> On 8/23/18 1:21 PM, David Hildenbrand wrote: >>>>> On 23.08.2018 13:05, Janosch Frank wrote: >>>>>> On 8/23/18 12:25 PM, Pierre Morel wrote: >>>>>>> The comment preceding the shadow_crycb function is >>>>>>> misleading, we effectively accept FORMAT2 CRYCB in the >>>>>>> guest. >>>>>> >>>>>> I beg to differ: >>>>>> >>>>>> if (!(crycbd_o & vcpu->arch.sie_block->crycbd & CRYCB_FORMAT1)) >>>>>> return 0; >>>>> >>>>> FORMAT2 includes bit FORMAT1 (backwards compatible) >>>> >>>> Right, this check is very misleading because of the constant, we >>>> effectively test against Format 0 and Format 2. >>>> >>>> Can we make this clearer by explicitly ANDing 0x01 or adding a comment? >>> >>> yes, done, I modified the comment in front of the function. >> >> Which is not what I want, what I want is: >> >> /* CRYCB_FORMAT2 includes the bit for CRYCB_FORMAT1, so we allow both >> formats here */ >> if (!(crycbd_o & vcpu->arch.sie_block->crycbd & CRYCB_FORMAT1)) >> return 0; > > While it's not wrong, it is also not required. And it might soon be > obsolete again (with APXA, as you said, there we always have to check). > > But I'll leave that to you > I have not checked the vfio-ap patches, Pierre just told me that it goes away in a few weeks anyway, so let's leave it out.
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