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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Steve Sistare <steven.sistare@oracle.com>
Cc: kvm@vger.kernel.org, Alex Williamson <alex.williamson@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>
Subject: Re: [PATCH V1 0/8] vfio virtual address update redo
Date: Wed, 7 Dec 2022 11:23:51 -0400	[thread overview]
Message-ID: <Y5CwB9J7K8pemFFK@ziepe.ca> (raw)
In-Reply-To: <1670363753-249738-1-git-send-email-steven.sistare@oracle.com>

On Tue, Dec 06, 2022 at 01:55:45PM -0800, Steve Sistare wrote:

> Lastly, if a task exits or execs, and it still owns any dma mappings, they
> are unmapped and unpinned.  This guarantees that pages do not remain pinned
> indefinitely if a vfio descriptor is leaked to another process, and requires
> tasks to explicitly transfer ownership of dma (and hence locked_vm) to a new
> task and mm when continued operation is desired.  The vfio driver maps a
> special vma so it can detect exit and exec, via the vm_operations_struct
> close callback.

I don't think any of this is necessary. If a VFIO FD is "leaked" to
another process there are many hostile things that process can do
beyond invoke this new ioctl. Considering the complexity I prefer to
drop this.

Jason

      parent reply	other threads:[~2022-12-07 15:23 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-06 21:55 [PATCH V1 0/8] vfio virtual address update redo Steve Sistare
2022-12-06 21:55 ` [PATCH V1 1/8] vfio: delete interfaces to update vaddr Steve Sistare
2022-12-06 23:52   ` Alex Williamson
2022-12-07 14:26     ` Steven Sistare
2022-12-07 15:14       ` Alex Williamson
2023-05-17 16:12       ` Jason Gunthorpe
2023-05-17 17:35         ` Steven Sistare
2022-12-07 15:19     ` Jason Gunthorpe
2022-12-08 19:09       ` Steven Sistare
2022-12-08 19:44         ` Alex Williamson
2022-12-07 23:20   ` Jason Gunthorpe
2022-12-08 22:18   ` Alex Williamson
2022-12-06 21:55 ` [PATCH V1 2/8] vfio/type1: dma owner permission Steve Sistare
2022-12-07 15:28   ` Jason Gunthorpe
2022-12-08 20:13     ` Steven Sistare
2022-12-06 21:55 ` [PATCH V1 3/8] vfio: close dma owner Steve Sistare
2022-12-06 21:55 ` [PATCH V1 4/8] vfio/type1: " Steve Sistare
2022-12-06 21:55 ` [PATCH V1 5/8] vfio/type1: track locked_vm per dma Steve Sistare
2022-12-06 21:55 ` [PATCH V1 6/8] vfio/type1: update vaddr Steve Sistare
2022-12-06 21:55 ` [PATCH V1 7/8] vfio: change dma owner Steve Sistare
2022-12-07 16:58   ` Jason Gunthorpe
2022-12-08 16:48     ` Steven Sistare
2022-12-08 17:15       ` Jason Gunthorpe
2022-12-08 17:39         ` Steven Sistare
2022-12-08 17:46           ` Jason Gunthorpe
2022-12-06 21:55 ` [PATCH V1 8/8] vfio/type1: " Steve Sistare
2022-12-07 17:00   ` Jason Gunthorpe
2022-12-08  7:22   ` Dan Carpenter
2022-12-07 15:23 ` Jason Gunthorpe [this message]

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