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 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 ?

--
Sander

> Thanks, Roger.
> ---8<---
> diff --git a/xen/drivers/passthrough/x86/iommu.c 
> b/xen/drivers/passthrough/x86/iommu.c
> index e40d7a7d7b..4fd75d4105 100644
> --- a/xen/drivers/passthrough/x86/iommu.c
> +++ b/xen/drivers/passthrough/x86/iommu.c
> @@ -241,10 +241,11 @@ void __hwdom_init arch_iommu_hwdom_init(struct domain 
> *d)
>  
>          if ( !hwdom_iommu_map(d, pfn, max_pfn) )
>              continue;
> -
> +#if 0
>          if ( paging_mode_translate(d) )
>              rc = set_identity_p2m_entry(d, pfn, p2m_access_rw, 0);
>          else
> +#endif
>              rc = iommu_map(d, _dfn(pfn), _mfn(pfn), PAGE_ORDER_4K,
>                             IOMMUF_readable | IOMMUF_writable, &flush_flags);
>  
> 


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