From: Scott Wood <scottwood@freescale.com>
To: Alexander Graf <agraf@suse.de>
Cc: kvm-ppc@vger.kernel.org, "Jörg Sommer" <joerg@alea.gnuu.de>,
"KVM list" <kvm@vger.kernel.org>
Subject: Re: [PATCH 1/4] KVM: PPC: Book3s: PR: Disable preemption in vcpu_run
Date: Tue, 13 Dec 2011 21:15:07 +0000 [thread overview]
Message-ID: <4EE7C05B.3020709@freescale.com> (raw)
In-Reply-To: <9FD32B52-754D-494D-8478-CAD3FDFAB586@suse.de>
On 12/09/2011 05:18 PM, Alexander Graf wrote:
>
> On 09.12.2011, at 19:19, Scott Wood wrote:
>
>> Shouldn't you really have interrupts disabled here, as booke does?
>
> Ah, thanks for the reminder. Yeah, we probably want to disable
> interrupts in parallel to checking for signals (basically from one
> signal check point to world switch). I'm just not 100% sure how to
> easily sync the C and asm code on the first entry though. Doing
> local_irq_disable in C and undoing it in asm could become ugly with
> lazy interrupt disabling.
Lots of things get ugly with lazy interrupt disabling. :-(
There should be other examples of handling the lazy EE stuff in asm
code. After you hard-disable, you should just need to poke the right
fields in the PACA with the state you plan to end up in after the rfi,
similar to exception return.
-Scott
WARNING: multiple messages have this Message-ID (diff)
From: Scott Wood <scottwood@freescale.com>
To: Alexander Graf <agraf@suse.de>
Cc: kvm-ppc@vger.kernel.org, "Jörg Sommer" <joerg@alea.gnuu.de>,
"KVM list" <kvm@vger.kernel.org>
Subject: Re: [PATCH 1/4] KVM: PPC: Book3s: PR: Disable preemption in vcpu_run
Date: Tue, 13 Dec 2011 15:15:07 -0600 [thread overview]
Message-ID: <4EE7C05B.3020709@freescale.com> (raw)
In-Reply-To: <9FD32B52-754D-494D-8478-CAD3FDFAB586@suse.de>
On 12/09/2011 05:18 PM, Alexander Graf wrote:
>
> On 09.12.2011, at 19:19, Scott Wood wrote:
>
>> Shouldn't you really have interrupts disabled here, as booke does?
>
> Ah, thanks for the reminder. Yeah, we probably want to disable
> interrupts in parallel to checking for signals (basically from one
> signal check point to world switch). I'm just not 100% sure how to
> easily sync the C and asm code on the first entry though. Doing
> local_irq_disable in C and undoing it in asm could become ugly with
> lazy interrupt disabling.
Lots of things get ugly with lazy interrupt disabling. :-(
There should be other examples of handling the lazy EE stuff in asm
code. After you hard-disable, you should just need to poke the right
fields in the PACA with the state you plan to end up in after the rfi,
similar to exception return.
-Scott
next prev parent reply other threads:[~2011-12-13 21:15 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-09 15:26 [PATCH 0/4] Fix book3s-pr KVM with preemption Alexander Graf
2011-12-09 15:26 ` Alexander Graf
2011-12-09 15:26 ` [PATCH 1/4] KVM: PPC: Book3s: PR: Disable preemption in vcpu_run Alexander Graf
2011-12-09 15:26 ` Alexander Graf
2011-12-09 18:19 ` Scott Wood
2011-12-09 18:19 ` Scott Wood
2011-12-09 23:18 ` Alexander Graf
2011-12-09 23:18 ` Alexander Graf
2011-12-13 21:15 ` Scott Wood [this message]
2011-12-13 21:15 ` Scott Wood
2011-12-09 15:26 ` [PATCH 2/4] KVM: PPC: Book3s: PR: No irq_disable " Alexander Graf
2011-12-09 15:26 ` Alexander Graf
2011-12-09 15:26 ` [PATCH 3/4] KVM: PPC: Use get/set for to_svcpu to help preemption Alexander Graf
2011-12-09 15:26 ` Alexander Graf
2011-12-09 15:26 ` [PATCH 4/4] KVM: PPC: align vcpu_kick with x86 Alexander Graf
2011-12-09 15:26 ` Alexander Graf
2011-12-09 18:19 ` Scott Wood
2011-12-09 18:19 ` Scott Wood
2011-12-09 19:10 ` Alexander Graf
2011-12-09 19:10 ` Alexander Graf
2011-12-09 19:15 ` Scott Wood
2011-12-09 19:15 ` Scott Wood
2011-12-09 23:15 ` Alexander Graf
2011-12-09 23:15 ` Alexander Graf
2011-12-12 17:32 ` Scott Wood
2011-12-12 17:32 ` Scott Wood
2011-12-23 12:56 ` Alexander Graf
2011-12-23 12:56 ` Alexander Graf
2011-12-23 21:50 ` Benjamin Herrenschmidt
2011-12-23 21:50 ` Benjamin Herrenschmidt
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