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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Juergen Gross <jgross@suse.com>,
	"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: Re: PCI-passthrough for 32 bit guests and high MMIO addresses
Date: Fri, 21 Nov 2014 14:45:19 +0000	[thread overview]
Message-ID: <546F4FFF.1080101@citrix.com> (raw)
In-Reply-To: <546F4E86.8060801@suse.com>

On 21/11/14 14:39, Juergen Gross wrote:
> Hi,
>
> again a fallout from my "linear p2m list" tests:
>
> Trying to do PCI-passthrough with a 32-bit pv-domain I passed the
> wrong device to the domain. The MMIO address was too large for a
> MFN of a 32-bit system (it was 380003200000-3800036fffff).
>
> Instead of rejecting the operation Xen tried to perform it resulting
> in a (quite understandable) failure in the domU.
>
> I think either the hypervisor or the tools should refuse to do
> PCI-passthrough in this case.
>

What actually goes wrong?  Does the 32bit guest truncate the MMIO region
to 44 bits and try to map that?

I would completely agree that something (libxl?) should refuse this
attempt to do passthrough, but I think pci-front should also kick up a
fuss if it is able to detect this error.

~Andrew

  reply	other threads:[~2014-11-21 14:45 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-21 14:39 PCI-passthrough for 32 bit guests and high MMIO addresses Juergen Gross
2014-11-21 14:45 ` Andrew Cooper [this message]
2014-11-21 15:04   ` Juergen Gross
2014-11-21 15:29     ` Andrew Cooper
2014-11-21 14:54 ` Jan Beulich
2014-11-21 15:01   ` Andrew Cooper
2014-11-21 15:38     ` Jan Beulich
2014-11-21 15:48       ` David Vrabel
2014-11-21 16:00         ` Jan Beulich
2014-11-21 16:01           ` David Vrabel
     [not found] ` <546F60470200007800049D06@suse.com>
2014-11-21 15:17   ` Juergen Gross
2014-11-21 15:40     ` Jan Beulich

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