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From: Avi Kivity <avi@redhat.com>
To: Max Filippov <jcmvbkbc@gmail.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>, qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] Xtensa misuse of tb_invalidate_phys_page_range()?
Date: Sun, 25 Mar 2012 11:53:33 +0200	[thread overview]
Message-ID: <4F6EEB1D.5090008@redhat.com> (raw)
In-Reply-To: <4F6E7C4E.9090409@gmail.com>

On 03/25/2012 04:00 AM, Max Filippov wrote:
>>
>> Since I'm rewriting this area, don't worry about efficiency.  Let's get
>> it correct and after the rewrite we can reexamine efficiency.
>>
>> I imagine you'll need something like breakpoint_invalidate().
>
> The following RFC patch takes the obvious approach of sharing the
> breakpoint_invalidate
> implementation to address this issue. 

Looks good.

> But if we're talking about correctness it's not
> 100% correct, because guest TLB is independent of both instruction
> breakpoints and
> zero overhead loops, and at the moment of TB invalidation relevant TLB
> mapping may not
> exist.
>
> Even if we managed to record physical addresses of TBs at the current
> IBREAKA/LEND, it's
> not enough because we need to invalidate TBs both at the old and at
> the new IBREAKA/LEND
> virtual addresses.
>
> What do you think, do we need yet another address-to-TB map?
>

No idea what all that means, sorry.

-- 
error compiling committee.c: too many arguments to function

      parent reply	other threads:[~2012-03-25  9:53 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-19 11:58 [Qemu-devel] Xtensa misuse of tb_invalidate_phys_page_range()? Avi Kivity
2012-03-19 13:51 ` Max Filippov
2012-03-19 14:08   ` Avi Kivity
2012-03-25  2:00     ` Max Filippov
2012-03-25  2:04       ` [Qemu-devel] [RFC] target-xtensa: fix tb invalidation for IBREAK and LOOP Max Filippov
2012-03-25  9:53       ` Avi Kivity [this message]

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