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Re: [Xen-devel] [PATCH] add support for XCHG instruction accessingAPIC

To: "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] add support for XCHG instruction accessingAPIC
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Wed, 5 Apr 2006 19:06:53 +0100
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx, Boris Ostrovsky <bostrovsky@xxxxxxxxxxxxxxx>
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On 5 Apr 2006, at 17:50, Jiang, Yunhong wrote:

I think the reason we don't take any lock here is; we are sure this is just used for local APIC range. However, if in future someone adds another MMIO range or if IOAPIC is accessed with XCHG (will this happen?), this may have potential issue.

So I'd suggest adding comments that we didn't take any lock here, or add a check to make sure the range is on local APIC range.

There is a comment in the patch I applied, and that section of code is specific to LAPIC handling.

 -- Keir

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