Messages in this thread | | | Date | Tue, 25 Sep 2018 11:09:48 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH] Changing the AMD IOMMU API path to work in an atomic context which is necessary for any custom drivers using the IOMMU API while holding a spinlock. |
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On Fri, Aug 24, 2018 at 02:28:49PM +0000, murphyt7@tcd.ie wrote: > From: Tom Murphy <murphyt7@tcd.ie> > > --- > > This patch allows the IOMMU API path in the AMD driver to be called > from an atomic context. This is useful for anyone building a driver > which needs to call the IOMMU API while holding a spinlock.
A bit more context would be helpful here. This is a pretty intrusive change since we will drain the memory allocators atomic pools now while building page-tables. This needs some more justification than just 'some drivers might need it'.
Further, if we really address this problem it needs to happen through the IOMMU-API, because the functions you are patching are called from iommu_map()/iommu_unmap(), and these functions are allowed to sleep.
So the required approach here would be to introduce something like iommu_map_atomic()/iommu_unmap_atomic() and implement call-backs for that in more than just one driver.
Regards,
Joerg
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