Re: [PATCH] iommu/vt-d: Handle hotplug devices' default identity mapping setting

[Lu Baolu]

Hi James,

On 2/22/19 2:38 PM, James Dong wrote:
> Tried this patch, and the same DMAR fault message came out.
>
> Guess it is because of the iommu code path for hotplug devices. If a hotplug
> device is rescanned after removal, iommu_bus_notifier will be called as part
> of the notifier chains to handle BUS_NOTIFY_ADD_DEVICE event. Along the code
> path, intel_iommu_ops->add_device() created an iommu group for this hotplug
> device, but failed to create an iommu domain because of the default domain
> type IOMMU_DOMAIN_IDENTITY imposed by current IOMMU command line option got
> declined by intel_iommu_ops->domain_alloc().
>
> In your patch, function find_or_alloc_domain() is not even in the code path
> of BUS_NOTIFY_ADD_DEVICE event notifier chain.
>
> Please let us know if your have more concerns and suggestions.

Can I reproduce this with a local machine? If so, how should I do?

> Best Regards,
> James

Best regards,
Lu Baolu