linux-kernel - Re: questions on how x86 uses IPI for tlb invalidates

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Message-Id: <200811190320.25720.nickpiggin@yahoo.com.au>
Date:	Wed, 19 Nov 2008 03:20:25 +1100
From:	Nick Piggin <nickpiggin@...oo.com.au>
To:	Kumar Gala <kumar.gala@...escale.com>
Cc:	linux-kernel Kernel <linux-kernel@...r.kernel.org>
Subject: Re: questions on how x86 uses IPI for tlb invalidates

On Wednesday 19 November 2008 03:06, Kumar Gala wrote:
> On Nov 18, 2008, at 10:03 AM, Nick Piggin wrote:

> > You can't do the broadcast TLB invalidates in kunmap_atomic.
> > All that's needed in that case is to just invalidate the local
> > CPU.
>
> Agreed, I was planning on fixing that.  I guess the high level
> question is if a broadcast invalidate can occur in soft or hard irq
> context.

x86 does them for unmapping KVA (except kunmap_atomic), and
unmapping UVA. Unmapping KVA (eg. kunmap, vunmap) is not allowed
in irq context.

So long as you fix kunmap_atomic, you shouldn't have a problems.
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