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Re: [Xen-devel] hypercall execution path?

  • To: Xen Developers <xen-devel@xxxxxxxxxxxxxxxxxxx>
  • From: Daniel Stodden <stodden@xxxxxxxxxx>
  • Date: Thu, 22 Feb 2007 19:18:09 +0100
  • Delivery-date: Thu, 22 Feb 2007 10:18:12 -0800
  • List-id: Xen developer discussion <xen-devel.lists.xensource.com>

On Thu, 2007-02-22 at 19:16 +0100, Daniel Stodden wrote:
> On Thu, 2007-02-22 at 12:17 -0500, Bryan D. Payne wrote:
> > I'm trying to trace the execution path taken by the system when I make a 
> > hypercall from a domU kernel.  What I'm seeing in the hypercall entry 
> > function in Xen is that the domU eip value points to a location in the 
> > domU hypercall page for the __HYPERCALL_sched_op hypercall, even though 
> > this is *not* the hypercall that I just called.
> > 
> > Could someone help clarify this for me?  Why would the vcpu for the 
> > guest domain have this seemingly incorrect eip value?
> hard to imagine :}
> apart from emulating execution, the single place i'm aware of playing
> with eip are continuations.
> so: what does it point at? what's the page address, which offset? 
> after looking into traps.c: take good care with the layout: hypercall
> pages on x86_32 are 32 (!) bytes per entry (not 8 as the loop body might
> suggest). are your calculations correct?

(i keep forgetting cc's)

Daniel Stodden
LRR     -      Lehrstuhl fÃr Rechnertechnik und Rechnerorganisation
Institut fÃr Informatik der TU MÃnchen             D-85748 Garching
http://www.lrr.in.tum.de/~stodden         mailto:stodden@xxxxxxxxxx
PGP Fingerprint: F5A4 1575 4C56 E26A 0B33  3D80 457E 82AE B0D8 735B

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