Re: [Xen-devel] Xen-unstable PVHdom0: Assertion 'IS_ALIGNED(dfn_x(dfn), (1ul << page_order))' failed at iommu.c:324

[Sander Eikelenboom <linux@xxxxxxxxxxxxxx>]

On 24/01/2019 08:50, Roger Pau Monné wrote:
> On Wed, Jan 23, 2019 at 08:56:48PM +0100, Sander Eikelenboom wrote:
>> On 23/01/2019 19:25, Roger Pau Monné wrote:
>>> On Wed, Jan 23, 2019 at 12:39:21AM +0100, Sander Eikelenboom wrote:
>>>> On 22/01/2019 17:14, Roger Pau Monné wrote:
>>>>> On Sun, Jan 20, 2019 at 11:09:25PM +0100, Sander Eikelenboom wrote:
>>>>>> On 18/01/2019 18:56, Roger Pau Monné wrote:
>>>>>>> On Fri, Jan 18, 2019 at 03:17:57PM +0100, Sander Eikelenboom wrote:
>>>>>>>> On 18/01/2019 13:50, Roger Pau Monné wrote:
>>>>>>>>> On Fri, Jan 18, 2019 at 01:03:04PM +0100, Sander Eikelenboom wrote:
>>>>>>>>>> Hi Roger,
>>>>>>>>>>
>>>>>>>>>> I gave PVH dom0 a spin, see how far I would get.
>>>>>>>>>
>>>>>>>>> Thanks!
>>>>>>>>>
>>>>>>>>>> With current xen-unstable unfortunately not that far, i got the 
>>>>>>>>>> splat below.
>>>>>>>>>
>>>>>>>>> Yes, this was already reported:
>>>>>>>>>
>>>>>>>>> https://lists.xenproject.org/archives/html/xen-devel/2019-01/msg01030.html
>>>>>>>>>> If you need more info, would like me to test a patch (or some other 
>>>>>>>>>> git tree/branch), 
>>>>>>>>>> I will be happy to give it a spin !
>>>>>>>>>
>>>>>>>>> Paul is working on a fix, but in the meantime just removing the
>>>>>>>>> assertions should be fine:
>>>>>>>>>
>>>>>>>>> ---8<---
>>>>>>>>> diff --git a/xen/drivers/passthrough/iommu.c 
>>>>>>>>> b/xen/drivers/passthrough/iommu.c
>>>>>>>>> index bd1af35a13..98e6fc35e2 100644
>>>>>>>>> --- a/xen/drivers/passthrough/iommu.c
>>>>>>>>> +++ b/xen/drivers/passthrough/iommu.c
>>>>>>>>> @@ -321,9 +321,6 @@ int iommu_map(struct domain *d, dfn_t dfn, mfn_t 
>>>>>>>>> mfn,
>>>>>>>>>      if ( !iommu_enabled || !hd->platform_ops )
>>>>>>>>>          return 0;
>>>>>>>>>  
>>>>>>>>> -    ASSERT(IS_ALIGNED(dfn_x(dfn), (1ul << page_order)));
>>>>>>>>> -    ASSERT(IS_ALIGNED(mfn_x(mfn), (1ul << page_order)));
>>>>>>>>> -
>>>>>>>>>      for ( i = 0; i < (1ul << page_order); i++ )
>>>>>>>>>      {
>>>>>>>>>          rc = hd->platform_ops->map_page(d, dfn_add(dfn, i), 
>>>>>>>>> mfn_add(mfn, i),
>>>>>>>>>
>>>>>>>>
>>>>>>>> I gave that a spin and i now get a seemingly endless stream of 
>>>>>>>> IO_PAGE_FAULTs
>>>>>>>
>>>>>>> You shouldn't get those page faults since they are for addresses that
>>>>>>> belong to a reserved region, and that should be mapped into the p2m.
>>>>>>> I've just tested on my AMD box and I'm also seeing errors (albeit
>>>>>>> different ones), so I guess something broke since I last fixed PVH
>>>>>>> Dom0 to boot on AMD hardware.
>>>>>>>
>>>>>>> I've also tested commit:
>>>>>>>
>>>>>>> commit fad6ba64a8c98bebb9374f390cc255fac05237ab (HEAD)
>>>>>>> Author: Roger Pau Monné <roger.pau@xxxxxxxxxx>
>>>>>>> Date:   Fri Nov 30 12:10:00 2018 +0100
>>>>>>> amd/iommu: skip host bridge devices when updating IOMMU page tables
>>>>>>>
>>>>>>> And it works on my AMD box and I'm able to boot as a PVH Dom0. Can you
>>>>>>> give this commit a spin?
>>>>>>>
>>>>>>> Thanks, Roger.
>>>>>>>
>>>>>>
>>>>>> Hi Roger,
>>>>>>
>>>>>> Tested that commit, but that didn't help.
>>>>>
>>>>> Thanks! Sorry for the delay, I got sidetracked with something else.
>>>>
>>>> No problem, it's not too urgent and probably a busy time with the 
>>>> remaining 4.12 stuff.
>>>>  
>>>>> Can you please post the serial log when using the above commit?
>>>>
>>>> Sure, I attached a log of:
>>>>  - fad6ba64a8c98bebb9374f390cc255fac05237ab  dom0 PVH unsuccesful boot
>>>>  - fad6ba64a8c98bebb9374f390cc255fac05237ab  dom0 PV    succesful boot
>>>
>>> Thanks. So you get the same IO page faults.
>>>
>>> I don't seem to be able to reproduce this behaviour on my AMD box, but
>>> that might be just luck. I've been finding some issues today related
>>> to the IOMMU, could you give the following patch a spin and paste the
>>> serial log that you get.
>>
>> Hi Roger,
>>
>> Sure, on top of what ?
>> - fad6ba64a8c98bebb9374f390cc255fac05237ab ?
>> - xen-unstable ?
>> - xen-unstable + Paul's patch ?
> 
> Hello,
> 
> Sorry for not proving the right context, let's try on top of
> xen-unstable + Paul's patch.
> 
> Thanks, Roger.
> 

Seems to be giving the same result (stream of IO_PAGE_FAULTs), serial
log attached.

--
Sander

Attachment: serial.log
Description: Text Data

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