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[Xen-devel] Re: [PATCH] Linux: 6 arguments hypercall v3

To: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Subject: [Xen-devel] Re: [PATCH] Linux: 6 arguments hypercall v3
From: Jean Guyader <jean.guyader@xxxxxxxxxxxxx>
Date: Fri, 24 Jun 2011 23:15:13 +0100
Cc: Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Jean Guyader <Jean.Guyader@xxxxxxxxxx>, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
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On 24/06 06:26, Jeremy Fitzhardinge wrote:
> On 06/24/2011 08:13 AM, Jean Guyader wrote:
> > Hi,
> >
> > This patch implements the 6 arguments hypercalls.
> > The sixth argument is passed using ebp or r9.
> >
> > Signed-off-by: Jean Guyader <jean.guyader@xxxxxxxxxx>
> > Reviewed-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> Looks OK, but I am still a bit worried about triggering compiler bugs
> with register pressure.  What compilers have you tested?

I only tested it gcc 4.4.

We could still use the v2 which is not as nice, but it doesn't try to
load eax twice. Let me know which one you will feel better about.

> What hypercalls have 6 args?

I'm planning on upstream v4v which is a inter vm memory transport
based on hypervisor memcpy. The send hypercall takes 6 arguments.


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