Re: [PATCH 15/18] iommu/vt-d: Add bind guest PASID support

[Andriy Shevchenko]

On Mon, Apr 08, 2019 at 04:59:30PM -0700, Jacob Pan wrote:
> When supporting guest SVA with emulated IOMMU, the guest PASID
> table is shadowed in VMM. Updates to guest vIOMMU PASID table
> will result in PASID cache flush which will be passed down to
> the host as bind guest PASID calls.
> 
> For the SL page tables, it will be harvested from device's
> default domain (request w/o PASID), or aux domain in case of
> mediated device.
> 
>     .-------------.  .---------------------------.
>     |   vIOMMU    |  | Guest process CR3, FL only|
>     |             |  '---------------------------'
>     .----------------/
>     | PASID Entry |--- PASID cache flush -
>     '-------------'                       |
>     |             |                       V
>     |             |                CR3 in GPA
>     '-------------'
> Guest
> ------| Shadow |--------------------------|--------
>       v        v                          v
> Host
>     .-------------.  .----------------------.
>     |   pIOMMU    |  | Bind FL for GVA-GPA  |
>     |             |  '----------------------'
>     .----------------/  |
>     | PASID Entry |     V (Nested xlate)
>     '----------------\.------------------------------.
>     |             |   |SL for GPA-HPA, default domain|
>     |             |   '------------------------------'
>     '-------------'
> Where:
>  - FL = First level/stage one page tables
>  - SL = Second level/stage two page tables

> +		list_for_each_entry(sdev, &svm->devs, list) {
> +			if (dev == sdev->dev) {
	...
> +			}
> +		}

This pattern occurs at least twice, perhaps something like

#define for_each_svm_dev()			\
	list_for_each_entry()			\
		if (dev != sdev->dev) {} else

?

-- 
With Best Regards,
Andy Shevchenko