Re: [Xen-devel] Xen-unstable-staging: Xen BUG at iommu_map.c:455

[Sander Eikelenboom <linux@xxxxxxxxxxxxxx>]

Wednesday, April 1, 2015, 1:38:34 AM, you wrote:

> On 31/03/2015 22:11, Sander Eikelenboom wrote:
>> Hi all,
>>
>> I just tested xen-unstable staging (changeset: git:0522407-dirty) 
>>
>> with revert of commit 1aeb1156fa43fe2cd2b5003995b20466cd19a622
>> (due to an already reported but not yet resolved issue)
>>
>> and build with qemu xen from 
>> git://xenbits.xen.org/staging/qemu-upstream-unstable.git
>> (to include the pci command register patch from Jan)
>>
>>
>> and now came across this new splat when starting an HVM with PCI passtrhough:

> Wow - you are getting all the fun bugs at the moment!

Hrmm i'm not so sure at the moment .. could also be a stale tree or is it just
that it's april 1st ..
*sigh* 
tried to git reset --hard to a known good changeset .. but it still seems
to fail, even with cold boot. 

So sorry for the noise and please ignore for the moment while i'm trying to
figure out what is fooling me :-)

--
sander



> Nothing has changed in the AMD IOMMU driver for a while, but the
> BUG_ON() is particularly unhelpful at identifying what went wrong.

> As a first pass triage, can you rerun with

> diff --git a/xen/drivers/passthrough/amd/iommu_map.c
> b/xen/drivers/passthrough/amd/iommu_map.c
> index 495ff5c..f15c324 100644
> --- a/xen/drivers/passthrough/amd/iommu_map.c
> +++ b/xen/drivers/passthrough/amd/iommu_map.c
> @@ -451,8 +451,9 @@ static int iommu_pde_from_gfn(struct domain *d,
> unsigned long pfn,
>      table = hd->arch.root_table;
>      level = hd->arch.paging_mode;

> -    BUG_ON( table == NULL || level < IOMMU_PAGING_MODE_LEVEL_1 ||
-            level >> IOMMU_PAGING_MODE_LEVEL_6 );
> +    BUG_ON(table == NULL);
> +    BUG_ON(level < IOMMU_PAGING_MODE_LEVEL_1);
+    BUG_ON(level >> IOMMU_PAGING_MODE_LEVEL_6);

>      next_table_mfn = page_to_mfn(table);

> which will help identify which of the conditions is failing.

> Can you please also provide the full serial log, including iommu=debug?

> ~Andrew



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel