Re: [PATCH v5 0/2] XSA-343 followup patches

[Jürgen Groß <jgross@xxxxxxxx>]

On 09.11.20 13:00, Jan Beulich wrote:
> On 09.11.2020 07:41, Juergen Gross wrote:
> > The patches for XSA-343 produced some fallout, especially the event
> > channel locking has shown to be problematic.
> >
> > Patch 1 is targeting fifo event channels for avoiding any races for the
> > case that the fifo queue has been changed for a specific event channel.
> >
> > The second patch is modifying the per event channel locking scheme in
> > order to avoid deadlocks and problems due to the event channel lock
> > having been changed to require IRQs off by the XSA-343 patches.
> >
> > Changes in V5:
> > - moved evtchn_write_[un]lock() to event_channel.c (Jan Beulich)
> > - used normal read_lock() in some cases (Jan Beulich)
> >
> > Changes in V4:
> > - switched to real rwlock
> >
> > Changes in V3:
> > - addressed comments
> >
> > Juergen Gross (2):
> >    xen/events: access last_priority and last_vcpu_id together
> >    xen/evtchn: rework per event channel lock
> Didn't you mean to add a 3rd patch here to drop the 2nd call to
> xsm_evtchn_send() again?
I wanted to that after this series has been accepted, but I can include
it here, of course.


Juergen

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