From: Paul Mackerras <paulus@samba.org>
To: Alexander Graf <agraf@suse.de>
Cc: Linuxppc-dev <linuxppc-dev@ozlabs.org>,
KVM list <kvm@vger.kernel.org>,
kvm-ppc@vger.kernel.org
Subject: Re: [PATCH 10/13] kvm/powerpc: Add support for Book3S processors in
Date: Fri, 27 May 2011 10:33:34 +0000 [thread overview]
Message-ID: <20110527103334.GA4236@brick.ozlabs.ibm.com> (raw)
In-Reply-To: <D8CAE971-9A97-4C02-8908-2B199C81947A@suse.de>
On Tue, May 17, 2011 at 12:17:50PM +0200, Alexander Graf wrote:
>
> On 16.05.2011, at 07:58, Paul Mackerras wrote:
>
> > I do the check there because I was having problems where, if the HDEC
> > goes negative before we do the partition switch, we would occasionally
> > not get the HDEC interrupt at all until the next time HDEC went
> > negative, ~ 8.4 seconds later.
>
> Yikes - so HDEC is edge and doesn't even keep the interrupt line up?
> That sounds like a serious hardware limitation. What if you only use
> HDEC and it triggers while interrupts are off in a critical section?
> Is the hardware really that broken?
If HDEC expires when interrupts are off, the HDEC interrupt stays
pending until interrupts get re-enabled. I'm not sure exactly what
the conditions are that cause an HDEC interrupt to get lost, but they
seem to involve at least a partition switch.
Paul.
next prev parent reply other threads:[~2011-05-27 10:33 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20110511103443.GA2837@brick.ozlabs.ibm.com>
[not found] ` <20110511104456.GK2837@brick.ozlabs.ibm.com>
2011-05-15 21:58 ` [PATCH 10/13] kvm/powerpc: Add support for Book3S processors in hypervisor mode Alexander Graf
2011-05-16 5:58 ` [PATCH 10/13] kvm/powerpc: Add support for Book3S processors in Paul Mackerras
2011-05-17 10:17 ` [PATCH 10/13] kvm/powerpc: Add support for Book3S processors in hypervisor mode Alexander Graf
2011-05-27 10:33 ` Paul Mackerras [this message]
2011-05-27 10:43 ` Alexander Graf
2011-05-27 20:59 ` Segher Boessenkool
2011-05-27 23:19 ` Alexander Graf
2011-05-28 1:07 ` Segher Boessenkool
2011-05-31 20:26 ` Jimi Xenidis
2011-05-31 22:34 ` Segher Boessenkool
2011-06-01 5:11 ` [PATCH 10/13] kvm/powerpc: Add support for Book3S processors in Paul Mackerras
[not found] ` <764651B6-6DDA-49DC-AA95-52CD86FF82D9@suse.de>
[not found] ` <20110517111536.GC7924@brick.ozlabs.ibm.com>
[not found] ` <14CFAA70-1747-4902-8CC1-4BE924CAD031@suse.de>
[not found] ` <4DD25F10.4030707@redhat.com>
[not found] ` <20110519052246.GA8165@drongo>
2011-05-19 6:01 ` [PATCH 0/13] Hypervisor-mode KVM on POWER7 Alexander Graf
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