Re: [Xen-devel] Question about alignment check in sh_x86_emulate

To:	"Tim Deegan" <Tim.Deegan@xxxxxxxxxx>
Subject:	Re: [Xen-devel] Question about alignment check in sh_x86_emulate_write
From:	"Trolle Selander" <trolle.selander@xxxxxxxxx>
Date:	Tue, 4 Dec 2007 16:13:11 +0100
Cc:	"Su, Disheng" <disheng.su@xxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date:	Tue, 04 Dec 2007 07:13:48 -0800
Dkim-signature:	v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:references; bh=b0FAEEm0fokgnVxWMpQRDQwT+rooF+ZboT6EUMBuYVc=; b=CCaTmVjiG2Ig20fDRvNo83dX//cf/axIJeuUYJJxpJ0sz8a7tPXhYfTG26FoKbEitRNTdQ/ioUlR8tam5tJWVZt2qCjLPT5F7rLGWPdJU7SNQdlOf3O9EHNGRjmBkllzROxY9+T5hZPWfLeh71cjeDwnIWOVXBJTQvHRVZIx4/w=
Domainkey-signature:	a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:references; b=Enm3G82IbSdtX1lkNTVfBMJbKfeX7gOm0jEZL6P9eMMeblfXgpdXSfOZoNxJW1JMbgpCH7LGKzqUBu5kch2N/Kg4pGeCIirAVccZVsRuSYAW5qmZkRCGFaRPWNSZgMdJLuNJBxkBv9ymeK9mvfQvAIAnDo9pv6w7uu50IebLXe4=
Envelope-to:	www-data@xxxxxxxxxxxxxxxxxx
In-reply-to:	<20071204140401.GD2062@xxxxxxxxxxxxxxxxxxxxx>
List-help:	<mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id:	Xen developer discussion <xen-devel.lists.xensource.com>
List-post:	<mailto:xen-devel@lists.xensource.com>
List-subscribe:	<http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe:	<http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References:	<FF386CB4AE0E4648B0A96060EC00F36C5BB8FA@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> <20071204124334.GB2062@xxxxxxxxxxxxxxxxxxxxx> <FF386CB4AE0E4648B0A96060EC00F36C5BB8FB@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> <20071204133319.GC2062@xxxxxxxxxxxxxxxxxxxxx> <515922b50712040552o4d454eefia0c0aaa70f446b5f@xxxxxxxxxxxxxx> <20071204140401.GD2062@xxxxxxxxxxxxxxxxxxxxx>
Sender:	xen-devel-bounces@xxxxxxxxxxxxxxxxxxx

Sadly, no. I can only guess what the OS/2 kernel is trying to do from the VMEXITs I see and disassembly of the relevant code - i have no source access or "inside knowledge". I could dig out disassembly of the code surrounding the mov instruction that actually does the write, if you're interested. I have it somewhere, but I didn't dig any deeper into this on the OS/2 side after I found I could get past it by removing the alignment check.

On Dec 4, 2007 3:04 PM, Tim Deegan < Tim.Deegan@xxxxxxxxxx> wrote:

At 14:52 +0100 on 04 Dec (1196779961), Trolle Selander wrote:
> To expand on my hastily posted comment before - OS/2 does get snagged on the
> check because of unaligned page table writes.

Well, I guess there's always one. :) Do you know what high-level
operation it's performing when it uses the unaligned write, BTW?

Cheers,

Tim.

--
Tim Deegan <Tim.Deegan@xxxxxxxxxx >
Principal Software Engineer, Citrix Systems.
[Company #5334508: XenSource UK Ltd, reg'd c/o EC2Y 5EB, UK.]

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

WARNING - OLD ARCHIVES

xen-devel

Re: [Xen-devel] Question about alignment check in sh_x86_emulate_write