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Re: [Xen-devel] TLB flushing in blktap kernel driver?

To: "Stephen C. Tweedie" <sct@xxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] TLB flushing in blktap kernel driver?
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Wed, 27 Sep 2006 14:30:04 +0100
Cc: Andrew Warfield <andrew.warfield@xxxxxxxxxxxx>, Julian Chesterfield <jac90@xxxxxxxxx>
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> However, I can't understand right now why we need the tlb flush here.
> If we're doing any grant table operations between dom0 and domU, then
> the HV should be doing the tlb flushes for us, shouldn't it?  And mere
> SMP synchronisation on a ring buffer requires a physical memory barrier,
> not a TLB synchronisation (and RING_PUSH_REQUESTS already does a wmb.)

Grant unmapping certainly guarantees to flush TLB entries.

 -- Keir

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