From: Avi Kivity <avi@qumranet.com>
To: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Pekka Paalanen <pq@iki.fi>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Christoph Hellwig <hch@infradead.org>,
Arjan van de Ven <arjan@infradead.org>,
Pavel Roskin <proski@gnu.org>,
Steven Rostedt <rostedt@goodmis.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
vegard.nossum@gmail.com
Subject: Re: mmiotrace bug: recursive probe hit
Date: Sat, 05 Apr 2008 18:58:08 +0300 [thread overview]
Message-ID: <47F7A190.9070401@qumranet.com> (raw)
In-Reply-To: <47F772E9.4000902@qumranet.com>
Avi Kivity wrote:
>>
>> For kmemcheck, I'd prefer the per-CPU page tables suggested by Ingo.
>> I'm having hard time understanding why that's a "ugly hack" compared
>> to using kvm for this...
>>
>
> It's not an ugly hack, but will be very very difficult. With mmu
> notifiers it's probably doable though:
>
> - the linux page tables are never loaded into cr3, but rather kept as
> a reference
> - page faults are by instantiating ptes into shadow page tables (which
> track the linux page tables)
> - mmu notifiers are used to drop shadow ptes when the linux ptes change
>
Actually, paravirt_ops is a much better match, as it also provides hooks
for setting cr3. I think you can implement per-cpu pagetables using
paravirt_ops without modifying core mm code at all.
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
next prev parent reply other threads:[~2008-04-05 16:02 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-09 14:40 [RFC] mmiotrace full patch, preview 2 Pekka Paalanen
2008-03-09 14:46 ` Pekka Paalanen
2008-03-27 23:13 ` Vegard Nossum
2008-03-28 18:24 ` Pekka Paalanen
2008-03-28 20:25 ` mmiotrace bug: recursive probe hit Pekka Paalanen
2008-03-30 17:26 ` Pekka Paalanen
2008-04-03 21:07 ` Pekka Paalanen
2008-04-03 21:40 ` Vegard Nossum
2008-04-04 13:18 ` Pekka Paalanen
2008-04-05 7:36 ` Avi Kivity
2008-04-05 7:40 ` Pekka Enberg
2008-04-05 12:39 ` Avi Kivity
2008-04-05 15:58 ` Avi Kivity [this message]
2008-04-06 17:32 ` Pekka Paalanen
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