[PATCH] iommu/amd: flush IOTLB for specific domains only (v2)

[Michel Dänzer]

On 19/05/17 07:02 PM, arindam.nath at amd.com wrote:
> From: Arindam Nath <arindam.nath at amd.com>
> 
> Change History
> --------------
> 
> v2: changes suggested by Joerg
> - add flush flag to improve efficiency of flush operation
> 
> v1:
> - The idea behind flush queues is to defer the IOTLB flushing
>   for domains for which the mappings are no longer valid. We
>   add such domains in queue_add(), and when the queue size
>   reaches FLUSH_QUEUE_SIZE, we perform __queue_flush().
> 
>   Since we have already taken lock before __queue_flush()
>   is called, we need to make sure the IOTLB flushing is
>   performed as quickly as possible.
> 
>   In the current implementation, we perform IOTLB flushing
>   for all domains irrespective of which ones were actually
>   added in the flush queue initially. This can be quite
>   expensive especially for domains for which unmapping is
>   not required at this point of time.
> 
>   This patch makes use of domain information in
>   'struct flush_queue_entry' to make sure we only flush
>   IOTLBs for domains who need it, skipping others.
> 
> Suggested-by: Joerg Roedel <joro at 8bytes.org>
> Signed-off-by: Arindam Nath <arindam.nath at amd.com>

Please add these tags:

Fixes: b1516a14657a ("iommu/amd: Implement flush queue")
Cc: stable at vger.kernel.org


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Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer