From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org, Paul Mackerras <paulus@ozlabs.org>
Subject: Re: [PATCH 1/5] powerpc/pseries: do not use msgsndp doorbells on POWER9 guests
Date: Mon, 10 Apr 2017 14:07:38 +1000 [thread overview]
Message-ID: <1491797258.4166.205.camel@kernel.crashing.org> (raw)
In-Reply-To: <20170410132245.16802599@roar.ozlabs.ibm.com>
On Mon, 2017-04-10 at 13:22 +1000, Nicholas Piggin wrote:
> On Sun, 09 Apr 2017 18:03:35 +1000
> > Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
>
> > On Fri, 2017-04-07 at 22:55 +1000, Nicholas Piggin wrote:
> > > POWER9 hypervisors will not necessarily run guest threads together on
> > > the same core at the same time, so msgsndp should not be used.
> >
> > Maybe we shouldn't advertise doorbells at all ?
>
> Possibly not. I don't know if there is a good way to switch it off
> in the guest from the host with device tree currently. Might be better
> to clear it early in the guest rather than test it here though?
Sure for now. Long term a separate DT entry would be good. Might be
worth re-enabling one day if we have HW virtualization of geust
doorbells.
Cheers,
Ben
next prev parent reply other threads:[~2017-04-10 4:07 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-07 12:55 [PATCH 0/5] doorbell patches for POWER9 Nicholas Piggin
2017-04-07 12:55 ` [PATCH 1/5] powerpc/pseries: do not use msgsndp doorbells on POWER9 guests Nicholas Piggin
2017-04-09 8:03 ` Benjamin Herrenschmidt
2017-04-10 3:22 ` Nicholas Piggin
2017-04-10 4:07 ` Benjamin Herrenschmidt [this message]
2017-04-10 4:28 ` Nicholas Piggin
2017-04-11 10:10 ` Michael Ellerman
2017-04-11 12:18 ` Nicholas Piggin
2017-04-07 12:55 ` [PATCH 2/5] powerpc: change the doorbell IPI calling convention Nicholas Piggin
2017-04-07 12:56 ` [PATCH 3/5] powerpc: Introduce msgsnd/doorbell barrier primitives Nicholas Piggin
2017-04-07 12:56 ` [PATCH 4/5] powerpc/64s: avoid branch for ppc_msgsnd Nicholas Piggin
2017-04-07 12:56 ` [PATCH 5/5] powerpc/powernv: POWER9 support for msgsnd/doorbell IPI Nicholas Piggin
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