From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?ISO-8859-1?Q?Roger_Pau_Monn=E9?= <roger.pau@citrix.com>
Subject: Re: [PATCH 1/3] iommu: set correct IOMMU entries when
 iommu_hap_pt_share == 0
Date: Tue, 8 Apr 2014 11:19:31 +0200
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To: Jan Beulich <JBeulich@suse.com>
Cc: xen-devel@lists.xenproject.org, Tim Deegan <tim@xen.org>
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On 08/04/14 10:30, Jan Beulich wrote:
>>>> On 07.04.14 at 18:02, <roger.pau@citrix.com> wrote:
>> If the memory map is not shared between HAP and IOMMU we fails to set
>> correct IOMMU mappings for memory types different than p2m_ram_rw.
>>
>> This patchs adds IOMMU support for the following memory types:
>> p2m_grant_map_rw, p2m_map_foreign, p2m_ram_ro and p2m_grant_map_ro.
> 
> I'm curious about the justification for p2m_map_foreign; the others
> I agree with.

Thanks for the review, I didn't see a reason to not allow DMA transfers
to/from foreign pages, although there's no user of foreign pages that
use DMA.

> 
> I also wonder whether p2m_ram_logdirty shouldn't be treated
> equally to p2m_ram_rw: It's clearly better to have some video
> corruption than to kill the guest due to excessive IOMMU faults,
> should its kernel choose to DMA into the frame buffer. But at the
> very minimum this needs to be included alongside p2m_ram_ro.

Ack. I wasn't sure about p2m_ram_logdirty, so I just decided to not
include it. I will add it to my next revision as a RW zone if that's fine.

Roger.