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Re: [Qemu-devel] Xtensa misuse of tb_invalidate_phys_page_range()?


From: Avi Kivity
Subject: Re: [Qemu-devel] Xtensa misuse of tb_invalidate_phys_page_range()?
Date: Sun, 25 Mar 2012 11:53:33 +0200
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.1) Gecko/20120216 Thunderbird/10.0.1

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




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