Re: questions on how x86 uses IPI for tlb invalidates

From: Nick Piggin
Date: Tue Nov 18 2008 - 11:20:48 EST


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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