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From: Julien Grall <julien.grall@linaro.org>
To: Jan Beulich <JBeulich@suse.com>,
	Arianna Avanzini <avanzini.arianna@gmail.com>
Cc: julien.grall@citrix.com, paolo.valente@unimore.it, keir@xen.org,
	stefano.stabellini@eu.citrix.com, Ian.Jackson@eu.citrix.com,
	dario.faggioli@citrix.com, tim@xen.org, xen-devel@lists.xen.org,
	Ian.Campbell@eu.citrix.com, etrudeau@broadcom.com,
	viktor.kleinik@globallogic.com
Subject: Re: [PATCH v6 05/11] arch, x86: check if mapping exists before memory_mapping removes it
Date: Tue, 22 Apr 2014 09:53:37 +0100	[thread overview]
Message-ID: <53562E11.7040406@linaro.org> (raw)
In-Reply-To: <535645B2020000780000A956@nat28.tlf.novell.com>

Hi Jan,

On 22/04/14 09:34, Jan Beulich wrote:
>>>> On 21.04.14 at 15:44, <avanzini.arianna@gmail.com> wrote:
>> Currently, when a memory mapping is removed with the memory_mapping
>> DOMCTL, no check is performed on the existence of such a mapping.
>> This commit attempts to add such a consistency check to the code
>> performing the unmap.
>
> I think this goes too far: Did you check that all existing tool stacks
> actually pass a valid MFN for the unmap? It would seem quite natural
> to me if some didn't, since tool stacks can be expected to know what
> they're doing.


If the toolstack doesn't give a valid MFN that would mean that the 
toolstack can mess up the range permission.

On a previous mail, I suggested to skip the MFN parameter when the 
toolstack is unmapping the range. Xen will take care to translate the 
GFN into an MFN.

AFAIU, it's what we do on the other unmap hypercalls.

-- 
Julien Grall

  reply	other threads:[~2014-04-22  8:53 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-21 13:44 [PATCH v6 00/11] Implement the XEN_DOMCTL_memory_mapping hypercall for ARM Arianna Avanzini
2014-04-21 13:44 ` [PATCH v6 01/11] arch, arm: domain build: let dom0 access I/O memory of mapped devices Arianna Avanzini
2014-04-29 12:37   ` Julien Grall
2014-04-29 13:44     ` Julien Grall
2014-04-29 23:12       ` Arianna Avanzini
2014-04-21 13:44 ` [PATCH v6 02/11] arch, arm: add consistency check to REMOVE p2m changes Arianna Avanzini
2014-04-22 19:35   ` Julien Grall
2014-04-21 13:44 ` [PATCH v6 03/11] arch, arm: let map_mmio_regions() take pfn as parameters Arianna Avanzini
2014-04-28 13:13   ` Ian Campbell
2014-04-21 13:44 ` [PATCH v6 04/11] arch, arm: make pfn range passed to map_mmio_regions() inclusive Arianna Avanzini
2014-04-22 19:52   ` Julien Grall
2014-04-28 13:15     ` Ian Campbell
2014-04-21 13:44 ` [PATCH v6 05/11] arch, x86: check if mapping exists before memory_mapping removes it Arianna Avanzini
2014-04-22  8:34   ` Jan Beulich
2014-04-22  8:53     ` Julien Grall [this message]
2014-04-22  9:20       ` Jan Beulich
2014-04-21 13:44 ` [PATCH v6 06/11] xen, x86: factor out map and unmap from the memory_mapping DOMCTL Arianna Avanzini
2014-04-21 16:14   ` Andrew Cooper
2014-04-22  8:50     ` Jan Beulich
2014-04-22  8:48   ` Jan Beulich
2014-04-21 13:45 ` [PATCH v6 07/11] xen, common: move the memory_mapping DOMCTL hypercall to common code Arianna Avanzini
2014-04-22  8:55   ` Jan Beulich
2014-04-21 13:45 ` [PATCH v6 08/11] tools, libxl: parse optional start gfn from the iomem config option Arianna Avanzini
2014-04-22 19:57   ` Julien Grall
2014-04-28 13:20   ` Ian Campbell
2014-05-01 17:29     ` Julien Grall
2014-04-21 13:45 ` [PATCH v6 09/11] tools, libxl: add helpers to establish if guest is auto-translated Arianna Avanzini
2014-04-28 13:22   ` Ian Campbell
2014-04-21 13:45 ` [PATCH v6 10/11] tools, libxl: handle the iomem parameter with the memory_mapping hcall Arianna Avanzini
2014-04-22 20:03   ` Julien Grall
2014-04-28 13:25     ` Ian Campbell
2014-04-28 13:32       ` Julien Grall
2014-04-28 13:24   ` Ian Campbell
2014-04-21 13:45 ` [PATCH v6 11/11] xen, common: do not implicitly permit access to mapped I/O memory Arianna Avanzini
2014-04-22  9:12   ` Jan Beulich
2014-04-28 13:33     ` Ian Campbell
2014-04-28 13:54       ` Jan Beulich
2014-04-28 14:20         ` Ian Campbell
2014-04-28 13:28   ` Ian Campbell

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