On 10/31/2018 01:29 PM, Cornelia Huck wrote: > On Wed, 31 Oct 2018 13:11:10 +0100 > Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote: > >> On 10/31/2018 11:09 AM, David Hildenbrand wrote: >>> On 25.10.18 14:37, Michael Mueller wrote: >>>> The Guest Information Area (GIB) and its mechanics is part of >>>> the AIV facility. It provides hardware support to process >>>> Adapter Interruptions (AI) for pagable storage mode guests. >>>> >>>> Whenever a guest cannot process an AI because none of its >>>> vcpus is running in SIE context, a GIB alert interruption is >>>> sent to and handled by the host program to dispatch a vcpu of >>>> the respective guest. >>>> >>>> Eventually, the AI is handled by the guest. >>> >>> >>> This does not apply to vSIE, right? >> >> We do not provide GISA, GIB and friends to the guest (e.g. we do not have >> the scp bits set). So right now we do not have anything to do for vsie. >> > > Any plans to do so in the future? Since GISA is just a performance optimization I am not sure if we really want to go down the path to also provide that for nested guests. Right now it this is just a speedup that the guest1 can use to improve the speed of guest2. If guest3 is a bit slower that should be fine for now. Pierre can you post your patches that make use of the GIB in vfio-ap so that everybody can see the full picture?
