Re: [Qemu-devel] [PATCH 2/2] spapr: Simulate CAS for qtest

[David Gibson]

On Fri, Mar 01, 2019 at 04:33:38PM -0600, Michael Roth wrote:
> Quoting Greg Kurz (2019-03-01 13:32:37)
> > The RTAS event hotplug code for machine types 2.8 and newer depends on
> > the CAS negotiated ov5 in order to work properly. However, there's no
> > CAS when running under qtest. There has been a tentative to trick the
> > code by faking the OV5_HP_EVT bit, but it turned out to break other
> > assumptions in the code and the change got reverted.
> > 
> > Go for a more general approach and simulate a CAS when running under
> > qtest. For simplicity, this pseudo CAS simple simulates the case where
> > the guest supports the same features as the machine. It is done at
> > reset time, just before we reset the DRCs, which could potentially
> > exercise the unplug code.
> > 
> > This allows to test unplug on spapr with both older and newer machine
> > types.
> > 
> > Suggested-by: Michael Roth <address@hidden>
> > Signed-off-by: Greg Kurz <address@hidden>
> 
> Tested-by: Michael Roth <address@hidden>
> Reviewed-by: Michael Roth <address@hidden>
> 
> Thanks for sending this!
> 
> Just now realizing we should probably apply the revert after this patch
> however, since the commit we're reverting fixes a `make check` test that
> is run by default, whereas this patch fixes one that only gets run if we
> run the tests with -m=slow specified.
> 
> Maybe David can do that on his end?

Applied in reverse order as suggested to ppc-for-4.0.  Thanks.

> 
> > ---
> >  hw/ppc/spapr.c |   11 +++++++++++
> >  1 file changed, 11 insertions(+)
> > 
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index b6a571b6f184..6da64ef7ee2b 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -29,6 +29,7 @@
> >  #include "qapi/visitor.h"
> >  #include "sysemu/sysemu.h"
> >  #include "sysemu/numa.h"
> > +#include "sysemu/qtest.h"
> >  #include "hw/hw.h"
> >  #include "qemu/log.h"
> >  #include "hw/fw-path-provider.h"
> > @@ -1711,6 +1712,16 @@ static void spapr_machine_reset(void)
> >       */
> >      spapr_irq_reset(spapr, &error_fatal);
> > 
> > +    /*
> > +     * There is no CAS under qtest. Simulate one to please the code that
> > +     * depends on spapr->ov5_cas. This is especially needed to test device
> > +     * unplug, so we do that before resetting the DRCs.
> > +     */
> > +    if (qtest_enabled()) {
> > +        spapr_ovec_cleanup(spapr->ov5_cas);
> > +        spapr->ov5_cas = spapr_ovec_clone(spapr->ov5);
> > +    }
> > +
> >      /* DRC reset may cause a device to be unplugged. This will cause 
> > troubles
> >       * if this device is used by another device (eg, a running vhost 
> > backend
> >       * will crash QEMU if the DIMM holding the vring goes away). To avoid 
> > such
> > 
> 

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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