On Fri, 28 Jul 2017 23:50:48 +0800 Dong Jia Shi <bjsdj...@linux.vnet.ibm.com> wrote:
> * Cornelia Huck <coh...@redhat.com> [2017-07-28 13:53:01 +0200]: > > > > You're bound to get different kinds of notifications: via a CRW with > > > > source channel path, via event information retrievable via CHSC > > > > (indicated by a CRW with source CSS), > > > Ha, I was not awre of this one before! > > > > That's the 'link incident' and 'resource accessibility' stuff. > My focus was trying to have the minimum stuff to make a Linux guest > working well -- basically, my working on prototype targeted to make the > output lschp and lscss corect and uptodate. I > > I will dig this and see if I need to do more stuff. You can probably skip this for now, unless you want to propagate the ficon-related stuff. Just plain channel-path related changes should already cover the interesting stuff. > > > My prototype work tries to sync the belowing information from host > > > kernel to qemu: > > > 1. the real SCHIB, so stsch from guest could get the updated path masks. > > > > How far do you want to go with mirroring? I think you need to modify at > > least the devno in the pmcw, no? > I didn't think this very deep. For now, I only sync the PIM, POM, PAM > and CHPIDs lazily. Also consider the pno bit and the pnom. > For devno... I need to think more. If the qemu command has a given > "devno" for the vfio-ccw device, maybe we should not override its dev_id > with the real one "device number". The guest should not be surprised by a different devno, so you need to be sure everything is consistent. > > > 3. still working on support CHSC store channel path description command. > > > > I'm currently wondering how many of those chscs are optional. OTOH, if > > a modern Linux guest cannot work properly without them, it makes no > > sense to leave them out. > Nod. > > But I think I need to define the criteria for "work properly". For > example, with the current code, a Linux guest with a passed through > device works, while lschp shows the Cfg. as 3 (not recognized), and the > Shared and PCHID as "-". For this case, do you think it "work properly"? It depends upon what you want to expose to the guest. Some configuration checking or management tools might be reporting a configuration deficiency (*might*, I do not know). Shared and PGID may be useful if the operator wants to perform some maintenance on the hardware (so they can figure out which systems/disks are affected), but the information should be available in the hypervisor as well, so I'm not sure whether it's a big deal.