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From: Marc Zyngier <marc.zyngier@arm.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: grant.likely@secretlab.ca, devicetree-discuss@lists.ozlabs.org,
	rob.herring@calxeda.com, david.vrabel@citrix.com,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2] ARM: DT: Add binding for GIC virtualization extentions (VGIC)
Date: Wed, 09 May 2012 21:36:43 +0200	[thread overview]
Message-ID: <a226ca6e8dd0370afeeb9aa1d67ddfde@localhost> (raw)
In-Reply-To: <201205091921.43299.arnd@arndb.de>

On Wed, 9 May 2012 19:21:42 +0000, Arnd Bergmann <arnd@arndb.de> wrote:
> On Wednesday 09 May 2012, Marc Zyngier wrote:
>> 
>> The GICv2 can have virtualization extension support, consisting
>> of an additional set of registers and interrupts. Add the necessary
>> binding to the GIC DT documentation.
>> 
>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> 
> Would it make sense to add a way to detect whether a GIC is virtual
> or real? Maybe an optional empty "virtual-gic" property or an additional
> "compatible" value. Even if we don't need it now, it might come in handy
> if we require it already.

I don't really see a need for this. When running on a virtual machine, the
kernel cannot tell if this is the real thing or not (the virtual CPU
interface looks exactly like the normal one once mapped into the guest
address space).

Or maybe I just didn't get your use case?

        M.
-- 
Fast, cheap, reliable. Pick two.

WARNING: multiple messages have this Message-ID (diff)
From: marc.zyngier@arm.com (Marc Zyngier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] ARM: DT: Add binding for GIC virtualization extentions (VGIC)
Date: Wed, 09 May 2012 21:36:43 +0200	[thread overview]
Message-ID: <a226ca6e8dd0370afeeb9aa1d67ddfde@localhost> (raw)
In-Reply-To: <201205091921.43299.arnd@arndb.de>

On Wed, 9 May 2012 19:21:42 +0000, Arnd Bergmann <arnd@arndb.de> wrote:
> On Wednesday 09 May 2012, Marc Zyngier wrote:
>> 
>> The GICv2 can have virtualization extension support, consisting
>> of an additional set of registers and interrupts. Add the necessary
>> binding to the GIC DT documentation.
>> 
>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> 
> Would it make sense to add a way to detect whether a GIC is virtual
> or real? Maybe an optional empty "virtual-gic" property or an additional
> "compatible" value. Even if we don't need it now, it might come in handy
> if we require it already.

I don't really see a need for this. When running on a virtual machine, the
kernel cannot tell if this is the real thing or not (the virtual CPU
interface looks exactly like the normal one once mapped into the guest
address space).

Or maybe I just didn't get your use case?

        M.
-- 
Fast, cheap, reliable. Pick two.

  reply	other threads:[~2012-05-09 19:36 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-09 17:57 [PATCH v2] ARM: DT: Add binding for GIC virtualization extentions (VGIC) Marc Zyngier
2012-05-09 17:57 ` Marc Zyngier
     [not found] ` <1336586277-28454-1-git-send-email-marc.zyngier-5wv7dgnIgG8@public.gmane.org>
2012-05-09 19:21   ` Arnd Bergmann
2012-05-09 19:21     ` Arnd Bergmann
2012-05-09 19:36     ` Marc Zyngier [this message]
2012-05-09 19:36       ` Marc Zyngier
2012-05-09 20:27       ` Arnd Bergmann
2012-05-09 20:27         ` Arnd Bergmann
     [not found]         ` <201205092027.50059.arnd-r2nGTMty4D4@public.gmane.org>
2012-05-09 20:42           ` Marc Zyngier
2012-05-09 20:42             ` Marc Zyngier
2012-05-09 20:47             ` Arnd Bergmann
2012-05-09 20:47               ` Arnd Bergmann
     [not found]               ` <201205092047.06852.arnd-r2nGTMty4D4@public.gmane.org>
2012-05-09 21:34                 ` Marc Zyngier
2012-05-09 21:34                   ` Marc Zyngier
2012-05-10 10:53                   ` Arnd Bergmann
2012-05-10 10:53                     ` Arnd Bergmann
     [not found]                     ` <201205101053.09954.arnd-r2nGTMty4D4@public.gmane.org>
2012-05-10 11:11                       ` Marc Zyngier
2012-05-10 11:11                         ` Marc Zyngier
2012-05-11 15:11                   ` Grant Likely
2012-05-11 15:11                     ` Grant Likely
2012-05-11 15:10                 ` Grant Likely
2012-05-11 15:10                   ` Grant Likely
2012-05-11 14:14 ` David Vrabel
2012-05-11 14:14   ` David Vrabel
2012-05-11 14:42   ` Marc Zyngier
2012-05-11 14:42     ` Marc Zyngier
     [not found]     ` <4FAD255A.4080504-5wv7dgnIgG8@public.gmane.org>
2012-05-11 14:43       ` David Vrabel
2012-05-11 14:43         ` David Vrabel
     [not found]         ` <4FAD25A1.2080106-Sxgqhf6Nn4DQT0dZR+AlfA@public.gmane.org>
2012-05-11 15:15           ` Grant Likely
2012-05-11 15:15             ` Grant Likely

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