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Re: [Xen-devel] Source of guest-physical address in PCI BAR for HVM doma

To: David Stone <unclestoner@xxxxxxxxx>
Subject: Re: [Xen-devel] Source of guest-physical address in PCI BAR for HVM domain?
From: Samuel Thibault <samuel.thibault@xxxxxxxxxxxxx>
Date: Fri, 4 Jan 2008 16:47:12 +0000
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David Stone, le Fri 04 Jan 2008 11:35:04 -0500, a écrit :
>   main_loop_wait
>   cpu_handle_ioreq
>   etc.
> So I guess this the PCI config-space write to set the BAR is passed to
> qemu-dm as a command from the hypervisor

Yes.

> this is happending early in the boot process before the guest OS
> proper is even running.  My understanding of how PCI systems work is
> that the BIOS first configures (a subset of) the PCI devices, and
> then the once the real OS is initializing it can re-configure any PCI
> devices it wants to.  Can someone tell me if this is correct?

That's what I remember too.

> If so, shouldn't the early PCI configuration from the BIOS be coming
> from qemu itself?

It is. It's odd you have troubles so early in the boot, is your
configuration a bit special in any way?

Samuel

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