From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Chen Baozi <baozich@gmail.com>,
Julien Grall <julien.grall@linaro.org>,
List Xen Developer <xen-devel@lists.xen.org>
Subject: Re: Problems when using latest git tree to boot xen on OMAP5
Date: Wed, 9 Oct 2013 12:29:53 +0100 [thread overview]
Message-ID: <alpine.DEB.2.02.1310091226010.26077@kaball.uk.xensource.com> (raw)
In-Reply-To: <1381317559.7600.3.camel@kazak.uk.xensource.com>
On Wed, 9 Oct 2013, Ian Campbell wrote:
> On Wed, 2013-10-09 at 12:15 +0100, Julien Grall wrote:
> > On 10/09/2013 09:11 AM, Ian Campbell wrote:
> > > Rather than whitelisting and mapping disabled devices through perhaps we
> > > should implement them as read 0xf (or 0x0) and write ignore?
> >
> > We can't assume that these values (0x0 or 0xf) won't affect dom0 behaviour.
>
> 0xff is what you would typically get back if there was no actual
> hardware present.
>
> > What about a new quirk to map all disabled device in dom0
> > (PLATFORM_QUIRK_DOM0_MAP_DISABLED_DEVICE)?
>
> Why is this not the default behaviour?
I think this is not a good idea: it prevents us from assigning one
device directly to a domain other than dom0 from Xen at boot time
(without going through something like PCI passthough).
Also if we really don't want dom0 to use a device, it makes perfect
sense that we don't map the device to it.
I would rather introduce PLATFORM_QUIRK_DOM0_EMULATE_DISABLED_DEVICE
and implement it with a simple write ignore, read 0xff.
next prev parent reply other threads:[~2013-10-09 11:29 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-04 14:11 Problems when using latest git tree to boot xen on OMAP5 Chen Baozi
2013-10-06 14:21 ` Chen Baozi
2013-10-07 8:39 ` Ian Campbell
2013-10-07 9:58 ` Chen Baozi
2013-10-07 10:01 ` Ian Campbell
2013-10-07 10:59 ` Julien Grall
2013-10-07 15:28 ` Chen Baozi
2013-10-07 15:44 ` Julien Grall
2013-10-08 13:54 ` Chen Baozi
2013-10-09 7:46 ` Chen Baozi
2013-10-09 8:11 ` Ian Campbell
2013-10-09 9:09 ` Chen Baozi
2013-10-09 11:15 ` Julien Grall
2013-10-09 11:19 ` Ian Campbell
2013-10-09 11:29 ` Stefano Stabellini [this message]
2013-10-09 12:01 ` Ian Campbell
2013-10-09 12:11 ` Stefano Stabellini
2013-10-09 11:29 ` Julien Grall
2013-10-09 12:05 ` Ian Campbell
2013-10-15 8:41 ` Chen Baozi
2013-10-10 8:05 ` Chen Baozi
2013-10-10 11:07 ` Julien Grall
2013-10-10 11:36 ` Chen Baozi
2013-10-10 12:04 ` Vaibhav Bedia
2013-10-07 10:19 ` Julien Grall
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