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RE: [Xen-devel] Testing status of HVM (Intel VT) on 64bit XENunstable c/

To: "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx>, "Steven Hand" <Steven.Hand@xxxxxxxxxxxx>
Subject: RE: [Xen-devel] Testing status of HVM (Intel VT) on 64bit XENunstable c/s 11616
From: "Li, Xin B" <xin.b.li@xxxxxxxxx>
Date: Thu, 28 Sep 2006 23:11:51 +0800
Cc: Xen Devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
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Thread-topic: [Xen-devel] Testing status of HVM (Intel VT) on 64bit XENunstable c/s 11616
 >This is probably because vmx_vmexit_handler() takes its regs 
>argument 'by
>value'. I expect the compiler has therefore decided it can 
>optimise away
>some writes to that argument because the result of the write 
>is not used
>inside vmx_vmexit_handler and it assumes the caller will discard the
>argument on return. Hence why this went away with a debug build -- we
>optimise less aggressively.
>
>Either the writeback needs to happen explicitly via
>guest_cpu_user_regs()-returned pointer. Or, more simply, we change the
>vmx_vmexit_handler interface. It'll have negligible cost to 
>pass a pointer.
>

Pretty clear and reasonable to me :-) 
Thanks
-Xin

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