Re: [Xen-devel] dom0 as pvh boot problem

["Zhang, Yang Z" <yang.z.zhang@xxxxxxxxx>]

Jan Beulich wrote on 2015-01-05:
>>>> Elena Ufimtseva <ufimtseva@xxxxxxxxx> 01/02/15 7:32 PM >>>
>> The last successful command is the reading status register of second
>> IOMMU
>> unit:
>> 
>> <snip from iommu_enable_translation() in
>> ./xen/drivers/passthrough/vtd/iommu.c>
>> 
>> 746:    sts = dmar_readl(iommu->reg, DMAR_GSTS_REG); 747:   
>> dmar_writel(iommu->reg, DMAR_GCMD_REG, sts | DMA_GCMD_TE);
>> 
>> </snip>
>> 
>> After dmar_writel for second iommu the machine hangs.
> 
> That's rather odd - you say it doesn't even reach the IOMMU_WAIT_OP()
> right after that? That would suggest a fault or other abnormal
> condition raised by the translation enabling (i.e. some problem with
> the page tables, albeit that should then have been a problem for the first 
> IOMMU already).
> Yet an eventual fault can't be delivered at that point due to
> interrupts being disabled. Perhaps the VT-d maintainers (now Cc-ed)
> have some suggestion as to what's going on or how to diagnose.

I am curious why pv dom0 boot fine. Will pvh dom0 share EPT table with VT-d? 
Maybe try with disable sharing to see whether helps.

> 
> Jan


Best regards,
Yang


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