Quoting Bharata B Rao (2015-02-27 03:52:09)
> On Fri, Feb 27, 2015 at 8:41 AM, Michael Roth <mdr...@linux.vnet.ibm.com>
> wrote:
> > +static void attach(sPAPRDRConnector *drc, DeviceState *d, void *fdt,
> > + int fdt_start_offset, bool coldplug, Error **errp)
> > +{
> > + DPRINTFN("drc: %x, attach", get_index(drc));
> > +
> > + if (drc->isolation_state != SPAPR_DR_ISOLATION_STATE_ISOLATED) {
> > + error_setg(errp, "an attached device is still awaiting release");
> > + return;
> > + }
> > + g_assert(drc->allocation_state == SPAPR_DR_ALLOCATION_STATE_UNUSABLE);
> > + g_assert(fdt || coldplug);
> > +
> > + /* NOTE: setting initial isolation state to UNISOLATED means we can't
> > + * detach unless guest has a userspace/kernel that moves this state
> > + * back to ISOLATED in response to an unplug event, or this is done
> > + * manually by the admin prior. if we force things while the guest
> > + * may be accessing the device, we can easily crash the guest, so we
> > + * we defer completion of removal in such cases to the reset() hook.
> > + */
> > + drc->isolation_state = SPAPR_DR_ISOLATION_STATE_UNISOLATED;
> > + drc->allocation_state = SPAPR_DR_ALLOCATION_STATE_USABLE;
>
> BTW shouldn't isolation_state and allocation_state be set to
> UNISOLATED and USABLE in response to guest's rtas-set-indicator calls
> ? At least, that is how it is done/expected for CPU hotplug case. Ref:
Well, for PCI we always start in USABLE (state diagram in PAPR+ 13.4), and
stay there. So set_allocation_state() should actually be a no-op for PCI;
there's no valid transition to UNUSABLE (or EXCHANGE/RECOVER).
For non-PCI, it looks like we should start in UNUSABLE, and let RTAS take it
from there. It also looks like the resource removal shouldn't be finalized
until there's a transition from ISOLATED/USABLE to ISOLATED/UNUSABLE.
I just pushed a patch here that I'm hoping will fix the non-PCI cases. Can
you give it a spin and let me know?
https://github.com/mdroth/qemu/commit/d91b0c6d6f794292e384cf129368aaae90294f5b
> kernel code arch/powerpc/platforms/pseries/dlpar.c:
> dlpar_acquire[release]_drc().
>
> Same question for detach().
>
> Regards,
> Bharata.
