From: Christoph Hellwig <hch@infradead.org>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Eric Farman <farman@linux.ibm.com>,
Joerg Roedel <jroedel@suse.de>,
kvm@vger.kernel.org, Cornelia Huck <cohuck@redhat.com>,
iommu@lists.linux-foundation.org,
Kevin Tian <kevin.tian@intel.com>,
Alex Williamson <alex.williamson@redhat.com>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH] vfio: Do not manipulate iommu dma_owner for fake iommu groups
Date: Thu, 19 May 2022 22:32:49 -0700 [thread overview]
Message-ID: <YocoAbMlb+zx2F1z@infradead.org> (raw)
In-Reply-To: <0-v1-9cfc47edbcd4+13546-vfio_dma_owner_fix_jgg@nvidia.com>
On Thu, May 19, 2022 at 02:03:48PM -0300, Jason Gunthorpe via iommu wrote:
> Since asserting dma ownership now causes the group to have its DMA blocked
> the iommu layer requires a working iommu. This means the dma_owner APIs
> cannot be used on the fake groups that VFIO creates. Test for this and
> avoid calling them.
>
> Otherwise asserting dma ownership will fail for VFIO mdev devices as a
> BLOCKING iommu_domain cannot be allocated due to the NULL iommu ops.
Fake iommu groups come back to bite again, part 42..
The patch looks good:
Reviewed-by: Christoph Hellwig <hch@lst.de>
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next prev parent reply other threads:[~2022-05-20 5:32 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-19 17:03 [PATCH] vfio: Do not manipulate iommu dma_owner for fake iommu groups Jason Gunthorpe via iommu
2022-05-20 1:33 ` Tian, Kevin
2022-05-20 5:32 ` Christoph Hellwig [this message]
2022-05-24 16:07 ` Alex Williamson
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