From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir@xensource.com>
Subject: Re: Permissive devices in Xen
Date: Sun, 08 Jul 2007 10:55:16 +0100
Message-ID: <C2B67314.A7E1%keir@xensource.com>
References: <20070708010556.GW3885@ics.muni.cz>
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To: Lukas Hejtmanek <xhejtman@ics.muni.cz>, xen-devel@lists.xensource.com
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On 8/7/07 02:05, "Lukas Hejtmanek" <xhejtman@ics.muni.cz> wrote:

> The PCI_COMMAND is handled in special way so that the device is
> enabled/disabled properly, am I right?
> 
> Why is PCI_INTERRUPT_LINE read from dev->irq and not from the config space?

dom0 will have correctly routed the interrupt,a nd stored the correct irq
number in dev->irq. The number in the config space may not be correct, or
may indicate only the irq number for legacy PCI-ISA link.

> Why the PCI address bars are handled in very different way? And it seems that
> writing these bars is never committed to the real devices. Why?

domU is not trusted to manage the i/o address space. We assume dom0 has set
up the values sanely and domU should have no reason to change them.

 -- Keir