From: George Dunlap <george.dunlap@eu.citrix.com>
To: Wei Liu <wei.liu2@citrix.com>, Jan Beulich <JBeulich@suse.com>,
tim@xen.org, keir@xen.org
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
Ian Campbell <ian.campbell@citrix.com>,
xen-devel@lists.xen.org
Subject: Re: Limitation in HVM physmap
Date: Fri, 18 Oct 2013 15:26:01 +0100 [thread overview]
Message-ID: <526144F9.5010108@eu.citrix.com> (raw)
In-Reply-To: <20131018142012.GB20185@zion.uk.xensource.com>
On 18/10/13 15:20, Wei Liu wrote:
> Hi Jan, Tim and Keir
>
> I currently run into the limitation of HVM's physmap: one MFN can only
> be mapped into one guest physical frame. Why is it designed like that?
>
> The scenario is that: when QEMU boots with OVMF (UEFI firmware), OVMF
> will first map the framebuffer to 0x80000000, resulting the framebuffer
> MFNs added to corresponding slots in physmap. A few moments later when
> Linux kernel loads, it tries to map framebuffer MFNs to 0xf00000000,
> which fails because those MFNs have already been mapped in other
> locations. Is there a way to fix this?
If I understood our f2f conversation correctly, not only this, but after
Linux has remapped it to 0xf, it makes calls into EFI which then access
it again at 0x8. So there is a period of time when it is accessed from
both places.
(Correct me if I misunderstood something...)
-George
next prev parent reply other threads:[~2013-10-18 14:26 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-18 14:20 Limitation in HVM physmap Wei Liu
2013-10-18 14:26 ` George Dunlap [this message]
2013-10-18 15:12 ` Paul Durrant
2013-10-18 14:28 ` Tim Deegan
2013-10-18 14:36 ` Wei Liu
2013-10-18 14:41 ` Tim Deegan
2013-10-18 14:56 ` Wei Liu
2013-10-18 14:59 ` Ian Campbell
2013-10-18 15:00 ` Ian Campbell
2013-10-18 15:04 ` Wei Liu
2013-10-18 15:06 ` George Dunlap
2013-10-18 15:07 ` Wei Liu
2013-10-18 15:09 ` Ian Campbell
2013-10-18 15:14 ` Stefano Stabellini
2013-10-18 14:47 ` Jan Beulich
2013-10-18 15:01 ` Wei Liu
2013-10-18 15:07 ` Ian Campbell
2013-10-18 15:30 ` Wei Liu
2013-10-18 15:09 ` Jan Beulich
2013-11-01 12:21 ` Wei Liu
2013-11-01 12:26 ` George Dunlap
2013-11-01 12:33 ` Ian Campbell
2013-11-01 12:45 ` Wei Liu
2013-11-01 12:49 ` Ian Campbell
2013-11-01 14:08 ` Wei Liu
2013-11-01 14:12 ` Ian Campbell
2013-11-01 14:19 ` Wei Liu
2013-11-01 14:31 ` Ian Campbell
2013-11-01 14:55 ` Wei Liu
2013-11-01 15:04 ` Ian Campbell
2013-11-04 9:28 ` Fabio Fantoni
2013-11-04 11:42 ` Wei Liu
2013-11-04 12:05 ` Fabio Fantoni
2013-11-04 12:17 ` Wei Liu
2013-11-04 14:08 ` Fabio Fantoni
2013-11-04 14:14 ` Wei Liu
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