From mboxrd@z Thu Jan  1 00:00:00 1970
From: Julien Grall <julien.grall@linaro.org>
Subject: Re: [RFC for-4.5 06/12] xen/passthrough: rework
 dom0_pvh_reqs to use it also on ARM
Date: Mon, 10 Feb 2014 17:42:28 +0000
Message-ID: <52F90F84.2090506@linaro.org>
References: <1391794991-5919-1-git-send-email-julien.grall@linaro.org>
	<1391794991-5919-7-git-send-email-julien.grall@linaro.org>
	<52F8F9F8.9000702@linaro.org>
	<52F90DF8020000780011AD65@nat28.tlf.novell.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
Received: from mail6.bemta14.messagelabs.com ([193.109.254.103])
	by lists.xen.org with esmtp (Exim 4.72)
	(envelope-from <julien.grall@linaro.org>) id 1WCusN-0004xD-Hh
	for xen-devel@lists.xenproject.org; Mon, 10 Feb 2014 17:42:35 +0000
Received: by mail-ea0-f169.google.com with SMTP id h10so3210189eak.28
	for <xen-devel@lists.xenproject.org>;
	Mon, 10 Feb 2014 09:42:33 -0800 (PST)
In-Reply-To: <52F90DF8020000780011AD65@nat28.tlf.novell.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Jan Beulich <JBeulich@suse.com>
Cc: ian.campbell@citrix.com, patches@linaro.org, tim@xen.org, stefano.stabellini@citrix.com, xen-devel@lists.xenproject.org, Xiantao Zhang <xiantao.zhang@intel.com>
List-Id: xen-devel@lists.xenproject.org

On 02/10/2014 04:35 PM, Jan Beulich wrote:
>>>> On 10.02.14 at 17:10, Julien Grall <julien.grall@linaro.org> wrote:
>> On 02/07/2014 05:43 PM, Julien Grall wrote:
>>> DOM0 on ARM will have the same requirements as DOM0 PVH when iommu is 
>> enabled.
>>> Both PVH and ARM guest has paging mode translate enabled, so Xen can use it
>>> to know if it needs to check the requirements.
>>>
>>> Rename the function and remove "pvh" word in the commit message.
>>>
>>> Signed-off-by: Julien Grall <julien.grall@linaro.org>
>>> Cc: Xiantao Zhang <xiantao.zhang@intel.com>
>>> Cc: Jan Beulich <jbeulich@suse.com>
>>> ---
>>>  xen/drivers/passthrough/iommu.c |   14 +++++++++-----
>>>  1 file changed, 9 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
>>> index 19b0e23..26a5d91 100644
>>> --- a/xen/drivers/passthrough/iommu.c
>>> +++ b/xen/drivers/passthrough/iommu.c
>>> @@ -130,13 +130,18 @@ int iommu_domain_init(struct domain *d)
>>>      return hd->platform_ops->init(d);
>>>  }
>>>  
>>> -static __init void check_dom0_pvh_reqs(struct domain *d)
>>> +static __init void check_dom0_reqs(struct domain *d)
>>>  {
>>> +    if ( !paging_mode_translate(d) )
>>> +        return;
>>> +
>>>      if ( !iommu_enabled )
>>> -        panic("Presently, iommu must be enabled for pvh dom0\n");
>>> +        panic("Presently, iommu must be enabled to use dom0 with translate 
>> "
>>> +              "paging mode\n");
>>
>> Hmmm... this change is wrong. I forgot that iommu doesn't exist on some
>> ARM platform (for instance Arndale).
>>
>> Do we really this check for PVH? If yes, I will add replace the check
>> by: is_pvh_domain(d) && !iommu_enabled.
> 
> Of course we need it: How would PVH Dom0 be able to do any kind
> of DMA without an IOMMU?

Right, on ARM we have the 1:1 memory mapping to avoid this issue.

I will fix it. Can I keep your ack on this patch?

> Jan
> 


-- 
Julien Grall