On Mon, 27 Nov 2017 19:39:32 -0500 Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx> wrote: > On 11/22/2017 08:47 AM, Cornelia Huck wrote: > > On Tue, 21 Nov 2017 11:08:01 -0500 > > Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx> wrote: > > > > > >> I am not quite sure what you are asking, but I'll attempt to answer > >> what I think you're asking. A new type of mediated matrix device > >> will be introduced to configure a virtual matrix for a guest that > >> provides the interfaces to map a virtual adapter/domain ID to one > >> or more real adapter/domain IDs. If by virtualization facility, > >> you are talking about the VFIO AP matrix driver, then yes, > >> the driver will handle ioctl requests based on the type of the > >> mediated matrix device through which the request was submitted: > >> > >> If the request is to configure the KVM guest's matrix: > >> > >> * If the mediated matrix device type is passthrough: > >> * Do validation of matrix > >> * Configure the APM, AQM and ADM in the KVM guest's CRYCB > >> according to the configuration specified via the mediated > >> device's sysfs attribute files. > >> * If the mediated matrix device type is virtual: > >> * Do validation of matrix > >> * No need to configure CRYCB since all instructions will be > >> intercepted > > Ok, so we would have two distinct paths here... > It depends upon what you mean by two distinct paths. Configuring the > mediated device would require a new mediated device type for virtualized > AP matrices. The ioctl for configuring the KVM guest's CRYCB would > require an additional check to determine whether the CRYCB need be > configured or not. Yes, the new type makes this distinct enough so that we can think about this later. > > > >> If the request is to execute an intercepted AP instruction: > >> > >> * If the mediated matrix device type is passthrough: > >> * Forward the instruction to the AP device and return the > >> result to QEMU. > >> > >> * If the mediated matrix device type is virtual: > >> > >> * Retrieve all of the real APQNs mapped to the virtual > >> adapter and domain IDs configured in the mediated matrix > >> device's sysfs attribute files > >> * If there is more than one APQN mapping, then determine > >> which would be best to use - algorithm TBD > >> * Forward the instruction to the AP device and return the > >> result. > > ...and two distinct paths for most instructions here as well. > The driver would require additional ioctls to handle > interception of all AP instructions for virtual matrices and additional > code to remap virtual APQNs to real APQNs and determine which real APQN > to which intercepted instructions should be forwarded. > > > >> Of course, these are just preliminary ideas at this time. > >> I've only prototyped the sysfs configuration interfaces. No > >> back end prototyping has been undertaken yet. If the ideas do > >> not pan out, however; I think virtualization can be introduced > >> as an independent design. > > Yes, let's cross that bridge when we get to it. > That is the plan. Given Pierre's objections, I thought it might help > to touch on this. OK, so I admit that I lost track a bit. Are there any remaining issues beyond the feature handling? Would it make sense to post a v2?
