> -----Original Message----- > From: Jan Beulich [mailto:[email protected]] > Sent: 18 May 2018 15:16 > To: Paul Durrant <[email protected]> > Cc: Anthony Perard <[email protected]>; Roger Pau Monne > <[email protected]>; Stefano Stabellini <[email protected]>; xen- > devel <[email protected]>; [email protected]; > [email protected]; [email protected]; [email protected]; Paolo > Bonzini <[email protected]>; Richard Henderson <[email protected]> > Subject: RE: [Xen-devel] [PATCH v2] xen-hvm: stop faking I/O to access PCI > config space > > >>> On 18.05.18 at 15:51, <[email protected]> wrote: > >> Sent: 18 May 2018 14:34 > >> To: Paul Durrant <[email protected]> > >> >>> On 18.05.18 at 15:00, <[email protected]> wrote: > >> > + QLIST_FOREACH(xendev, &state->dev_list, entry) { > >> > + unsigned int i; > >> > + uint32_t tmp; > >> > + > >> > + if (xendev->sbdf != sbdf) { > >> > + continue; > >> > + } > >> > + > >> > + if (!req->data_is_ptr) { > >> > + if (req->dir == IOREQ_READ) { > >> > + for (i = 0; i < req->count; i++) { > >> > + rw_config_req_item(xendev, req, i, &tmp); > >> > + req->data = tmp; > >> > + } > >> > + } else if (req->dir == IOREQ_WRITE) { > >> > + for (i = 0; i < req->count; i++) { > >> > + tmp = req->data; > >> > + rw_config_req_item(xendev, req, i, &tmp); > >> > + } > >> > + } > >> > >> Wouldn't it be more sensible to fail req->count != 1 requests here? > >> > > > > I'm wondering whether we'd want to handle count > 1 once we allow > MMCONFIG > > accesses though. I guess it would be easier just to defer that. > > For the data_is_ptr case - sure. But here? Or wait - are you thinking about > REP STOS (and the relatively useless REP LODS)? >
Yes. We'd need to cope with a rep stos if we had memory mapped access, but we don't need to worry about it until then I think. In the meantime I doubt any well behaved OS is going to do rep ins or rep outs to cfc so just aborting on count > 1 is probably fine. Paul > Jan > _______________________________________________ Xen-devel mailing list [email protected] https://lists.xenproject.org/mailman/listinfo/xen-devel
