From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Scott Wood <scottwood@freescale.com>
Cc: "tiejun.chen" <tiejun.chen@windriver.com>,
Bhushan Bharat-R65777 <R65777@freescale.com>,
Caraman Mihai Claudiu-B02008 <B02008@freescale.com>,
Wood Scott-B07421 <B07421@freescale.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"agraf@suse.de" <agraf@suse.de>,
"kvm-ppc@vger.kernel.org" <kvm-ppc@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [RFC][PATCH 1/1] kvm:ppc:booke-64: soft-disable interrupts
Date: Fri, 10 May 2013 08:07:00 +1000 [thread overview]
Message-ID: <1368137220.3715.14.camel@pasglop> (raw)
In-Reply-To: <1368134856.654.11@snotra>
On Thu, 2013-05-09 at 16:27 -0500, Scott Wood wrote:
> On 05/09/2013 07:37:42 AM, Benjamin Herrenschmidt wrote:
> > On Thu, 2013-05-09 at 17:44 +0800, tiejun.chen wrote:
> > >
> > > Actually in the case GS=1 even if EE=0, EXT/DEC/DBELL still occur
> > as I
> > > recall.
> >
> > Only if directed to the hypervisor.
>
> This is always the case with KVM, right? At least on booke...
Hrm, on A2 we could choose iirc. Well not DEC but EXT at least, I don't
remember about DBELL.
> > > > Case 1)
> > > > -> Local_irq_disable() will set soft_enabled = 0
> > > > -> Now Externel interrupt happens, there we set PACA_IRQ_EE in
> > > irq_happened, Also clears EE in SRR1 and rfi. So interrupts are hard
> > > disabled. No more other interrupt gated by MSR.EE can happen. Looks
> > > like the idea here is to not let a device keep on inserting
> > interrupt
> > > till the interrupt condition on device is cleared, right?
> >
> > The external interrupt line is level sensitive normally, so we have to
> > mask MSR:EE in that case or the interrupt would keep re-occurring
> > (note
> > that FSL has this concept of auto-acked interrupts via the on die MPIC
> > for which you can potentially use PACA_IRQ_EE_EDGE instead and avoid
> > having to mask MSR:EE).
>
> Note that if we do this, we can no longer leave the interrupt vector in
> EPR, and would have to track (potentially multiple different) pending
> external interrupts in software.
Right, you can have a little queue in the PACA and leave EE disabled if
it's full. You can probably get away with a queue of 1 though :-)
Cheers,
Ben.
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Scott Wood <scottwood@freescale.com>
Cc: Wood Scott-B07421 <B07421@freescale.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Caraman Mihai Claudiu-B02008 <B02008@freescale.com>,
"agraf@suse.de" <agraf@suse.de>,
"kvm-ppc@vger.kernel.org" <kvm-ppc@vger.kernel.org>,
"tiejun.chen" <tiejun.chen@windriver.com>,
Bhushan Bharat-R65777 <R65777@freescale.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [RFC][KVM][PATCH 1/1] kvm:ppc:booke-64: soft-disable interrupts
Date: Fri, 10 May 2013 08:07:00 +1000 [thread overview]
Message-ID: <1368137220.3715.14.camel@pasglop> (raw)
In-Reply-To: <1368134856.654.11@snotra>
On Thu, 2013-05-09 at 16:27 -0500, Scott Wood wrote:
> On 05/09/2013 07:37:42 AM, Benjamin Herrenschmidt wrote:
> > On Thu, 2013-05-09 at 17:44 +0800, tiejun.chen wrote:
> > >
> > > Actually in the case GS=1 even if EE=0, EXT/DEC/DBELL still occur
> > as I
> > > recall.
> >
> > Only if directed to the hypervisor.
>
> This is always the case with KVM, right? At least on booke...
Hrm, on A2 we could choose iirc. Well not DEC but EXT at least, I don't
remember about DBELL.
> > > > Case 1)
> > > > -> Local_irq_disable() will set soft_enabled = 0
> > > > -> Now Externel interrupt happens, there we set PACA_IRQ_EE in
> > > irq_happened, Also clears EE in SRR1 and rfi. So interrupts are hard
> > > disabled. No more other interrupt gated by MSR.EE can happen. Looks
> > > like the idea here is to not let a device keep on inserting
> > interrupt
> > > till the interrupt condition on device is cleared, right?
> >
> > The external interrupt line is level sensitive normally, so we have to
> > mask MSR:EE in that case or the interrupt would keep re-occurring
> > (note
> > that FSL has this concept of auto-acked interrupts via the on die MPIC
> > for which you can potentially use PACA_IRQ_EE_EDGE instead and avoid
> > having to mask MSR:EE).
>
> Note that if we do this, we can no longer leave the interrupt vector in
> EPR, and would have to track (potentially multiple different) pending
> external interrupts in software.
Right, you can have a little queue in the PACA and leave EE disabled if
it's full. You can probably get away with a queue of 1 though :-)
Cheers,
Ben.
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Scott Wood <scottwood@freescale.com>
Cc: "tiejun.chen" <tiejun.chen@windriver.com>,
Bhushan Bharat-R65777 <R65777@freescale.com>,
Caraman Mihai Claudiu-B02008 <B02008@freescale.com>,
Wood Scott-B07421 <B07421@freescale.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"agraf@suse.de" <agraf@suse.de>,
"kvm-ppc@vger.kernel.org" <kvm-ppc@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [RFC][KVM][PATCH 1/1] kvm:ppc:booke-64: soft-disable interrupts
Date: Thu, 09 May 2013 22:07:00 +0000 [thread overview]
Message-ID: <1368137220.3715.14.camel@pasglop> (raw)
In-Reply-To: <1368134856.654.11@snotra>
On Thu, 2013-05-09 at 16:27 -0500, Scott Wood wrote:
> On 05/09/2013 07:37:42 AM, Benjamin Herrenschmidt wrote:
> > On Thu, 2013-05-09 at 17:44 +0800, tiejun.chen wrote:
> > >
> > > Actually in the case GS=1 even if EE=0, EXT/DEC/DBELL still occur
> > as I
> > > recall.
> >
> > Only if directed to the hypervisor.
>
> This is always the case with KVM, right? At least on booke...
Hrm, on A2 we could choose iirc. Well not DEC but EXT at least, I don't
remember about DBELL.
> > > > Case 1)
> > > > -> Local_irq_disable() will set soft_enabled = 0
> > > > -> Now Externel interrupt happens, there we set PACA_IRQ_EE in
> > > irq_happened, Also clears EE in SRR1 and rfi. So interrupts are hard
> > > disabled. No more other interrupt gated by MSR.EE can happen. Looks
> > > like the idea here is to not let a device keep on inserting
> > interrupt
> > > till the interrupt condition on device is cleared, right?
> >
> > The external interrupt line is level sensitive normally, so we have to
> > mask MSR:EE in that case or the interrupt would keep re-occurring
> > (note
> > that FSL has this concept of auto-acked interrupts via the on die MPIC
> > for which you can potentially use PACA_IRQ_EE_EDGE instead and avoid
> > having to mask MSR:EE).
>
> Note that if we do this, we can no longer leave the interrupt vector in
> EPR, and would have to track (potentially multiple different) pending
> external interrupts in software.
Right, you can have a little queue in the PACA and leave EE disabled if
it's full. You can probably get away with a queue of 1 though :-)
Cheers,
Ben.
next prev parent reply other threads:[~2013-05-09 22:07 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-06 3:10 [RFC][KVM][PATCH 1/1] kvm:ppc:booke-64: soft-disable interrupts Tiejun Chen
2013-05-06 3:10 ` Tiejun Chen
2013-05-06 3:10 ` Tiejun Chen
2013-05-06 3:13 ` tiejun.chen
2013-05-06 3:13 ` tiejun.chen
2013-05-06 3:13 ` tiejun.chen
2013-05-06 23:50 ` Scott Wood
2013-05-06 23:50 ` Scott Wood
2013-05-07 1:56 ` tiejun.chen
2013-05-07 1:56 ` tiejun.chen
2013-05-07 1:56 ` tiejun.chen
2013-05-07 2:06 ` Scott Wood
2013-05-07 2:06 ` Scott Wood
2013-05-07 2:43 ` tiejun.chen
2013-05-07 2:43 ` tiejun.chen
2013-05-07 2:43 ` tiejun.chen
2013-05-07 3:04 ` Scott Wood
2013-05-07 3:04 ` Scott Wood
2013-05-08 13:14 ` Caraman Mihai Claudiu-B02008
2013-05-08 13:14 ` Caraman Mihai Claudiu-B02008
2013-05-09 7:33 ` Bhushan Bharat-R65777
2013-05-09 7:33 ` Bhushan Bharat-R65777
2013-05-09 7:47 ` tiejun.chen
2013-05-09 7:47 ` tiejun.chen
2013-05-09 7:47 ` tiejun.chen
2013-05-09 7:51 ` Bhushan Bharat-R65777
2013-05-09 7:51 ` Bhushan Bharat-R65777
2013-05-09 8:04 ` tiejun.chen
2013-05-09 8:04 ` tiejun.chen
2013-05-09 8:04 ` tiejun.chen
2013-05-09 8:08 ` Kevin Hao
2013-05-09 8:08 ` Kevin Hao
2013-05-09 8:08 ` Kevin Hao
2013-05-09 8:12 ` Bhushan Bharat-R65777
2013-05-09 8:12 ` Bhushan Bharat-R65777
2013-05-09 8:17 ` tiejun.chen
2013-05-09 8:17 ` tiejun.chen
2013-05-09 8:17 ` tiejun.chen
2013-05-09 8:26 ` Bhushan Bharat-R65777
2013-05-09 8:26 ` Bhushan Bharat-R65777
2013-05-09 8:21 ` Kevin Hao
2013-05-09 8:21 ` Kevin Hao
2013-05-09 8:21 ` Kevin Hao
2013-05-09 12:26 ` Benjamin Herrenschmidt
2013-05-09 12:26 ` Benjamin Herrenschmidt
2013-05-09 12:26 ` Benjamin Herrenschmidt
2013-05-09 8:23 ` Bhushan Bharat-R65777
2013-05-09 8:23 ` Bhushan Bharat-R65777
2013-05-09 9:44 ` tiejun.chen
2013-05-09 9:44 ` tiejun.chen
2013-05-09 9:44 ` tiejun.chen
2013-05-09 10:00 ` Bhushan Bharat-R65777
2013-05-09 10:00 ` Bhushan Bharat-R65777
2013-05-09 10:18 ` [RFC][PATCH " tiejun.chen
2013-05-09 10:18 ` [RFC][KVM][PATCH " tiejun.chen
2013-05-09 10:18 ` tiejun.chen
2013-05-09 11:21 ` Bhushan Bharat-R65777
2013-05-09 11:21 ` Bhushan Bharat-R65777
2013-05-09 11:35 ` tiejun.chen
2013-05-09 11:35 ` tiejun.chen
2013-05-09 11:35 ` tiejun.chen
2013-05-09 12:37 ` [RFC][PATCH " Benjamin Herrenschmidt
2013-05-09 12:37 ` [RFC][KVM][PATCH " Benjamin Herrenschmidt
2013-05-09 12:37 ` Benjamin Herrenschmidt
2013-05-09 13:28 ` David Laight
2013-05-09 13:28 ` David Laight
2013-05-09 13:28 ` David Laight
2013-05-09 22:01 ` Benjamin Herrenschmidt
2013-05-09 22:01 ` Benjamin Herrenschmidt
2013-05-09 22:01 ` Benjamin Herrenschmidt
2013-05-09 14:13 ` Chen, Tiejun
2013-05-09 14:13 ` Chen, Tiejun
2013-05-09 14:13 ` Chen, Tiejun
2013-05-09 21:27 ` Scott Wood
2013-05-09 21:27 ` Scott Wood
2013-05-09 22:07 ` Benjamin Herrenschmidt [this message]
2013-05-09 22:07 ` Benjamin Herrenschmidt
2013-05-09 22:07 ` Benjamin Herrenschmidt
2013-05-09 22:13 ` Scott Wood
2013-05-09 22:13 ` Scott Wood
2013-05-10 14:12 ` Kevin Hao
2013-05-10 14:12 ` Kevin Hao
2013-05-10 14:12 ` Kevin Hao
2013-05-10 21:49 ` Benjamin Herrenschmidt
2013-05-10 21:49 ` Benjamin Herrenschmidt
2013-05-10 21:49 ` Benjamin Herrenschmidt
2013-05-10 21:50 ` Benjamin Herrenschmidt
2013-05-10 21:50 ` Benjamin Herrenschmidt
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