On Wed, 10 Apr 2019 02:10:44 +0200 Halil Pasic <pasic@xxxxxxxxxxxxx> wrote: > On Tue, 9 Apr 2019 19:55:48 +0200 > Cornelia Huck <cohuck@xxxxxxxxxx> wrote: > > > On Fri, 5 Apr 2019 01:16:15 +0200 > > Halil Pasic <pasic@xxxxxxxxxxxxx> wrote: > > > Thus we need to make sure any memory that is used for communication with > > > the hypervisor is shared. > > > > In this context, does 'hypervisor' always mean 'QEMU/KVM'? If Other > > Hypervisors implement protected virtualization, we probably need to > > make sure that all common I/O layer control blocks are in the dma area > > (including e.g. QDIO), not just what virtio-ccw devices use. > > > > Hypervisor could theoretically be something different than QEMU/KVM. Yet, > as stated before, this series is about getting virtio-ccw working > (modulo the TODOs). Sure, just wanted to point it out. If this is "enable the common I/O layer, except for QDIO" or so, that would sound fine to me :) > > [..] > > > > > > > > So, this leaves some things I'm not sure about, especially as I do not > > know the architecture of this new feature. > > > > - This applies only to asynchronously handled things, it seems? So > > things like control blocks modified by stsch/msch/etc does not need > > special treatment? > > I had a feeble attempt at explaining this in the cover letter: > > * make sure that virtio-ccw specific stuff uses shared memory when > talking to the hypervisor (except communication blocks like ORB, these > are handled by the hypervisor) > > Unfortunately the last 'hypervisor' was supposed to be 'ultravisor'. > > I.e. the ultravisor will take care of exposing the control blocks > to the hypervisor (and of changes as well). Yeah, that "control blocks" or "communication blocks" leaves me a bit fuzzy :) So, what is a high-level summary of areas that need the treatment? What I get from looking at the patches so far, it's: - stuff that is written by the hypervisor's interrupt injection code: IRB, indicators, etc. - buffers that are filled by a channel program: sense, sense id, etc. - ccws themselves (because of translation?)
