From: Jason Gunthorpe <jgg@ziepe.ca>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Oded Gabbay" <oded.gabbay@gmail.com>,
"Inki Dae" <inki.dae@samsung.com>,
linux-samsung-soc <linux-samsung-soc@vger.kernel.org>,
"Jan Kara" <jack@suse.cz>,
"Joonyoung Shim" <jy0922.shim@samsung.com>,
"Pawel Osciak" <pawel@osciak.com>,
"John Hubbard" <jhubbard@nvidia.com>,
"Seung-Woo Kim" <sw0312.kim@samsung.com>,
LKML <linux-kernel@vger.kernel.org>,
"DRI Development" <dri-devel@lists.freedesktop.org>,
"Tomasz Figa" <tfiga@chromium.org>,
"Kyungmin Park" <kyungmin.park@samsung.com>,
"Linux MM" <linux-mm@kvack.org>,
"Jérôme Glisse" <jglisse@redhat.com>,
"Daniel Vetter" <daniel.vetter@intel.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"open list:DMA BUFFER SHARING FRAMEWORK"
<linux-media@vger.kernel.org>,
"Dan Williams" <dan.j.williams@intel.com>,
"Linux ARM" <linux-arm-kernel@lists.infradead.org>,
"Marek Szyprowski" <m.szyprowski@samsung.com>
Subject: Re: [PATCH 2/2] mm/frame-vec: use FOLL_LONGTERM
Date: Mon, 5 Oct 2020 15:37:04 -0300 [thread overview]
Message-ID: <20201005183704.GC5177@ziepe.ca> (raw)
In-Reply-To: <CAKMK7uFzxWF7V=7vkeNC-8shsPZRgdz9fYTsn0ayENv2BpnFEg@mail.gmail.com>
On Mon, Oct 05, 2020 at 08:16:33PM +0200, Daniel Vetter wrote:
> > kvm is some similar hack added for P2P DMA, see commit
> > add6a0cd1c5ba51b201e1361b05a5df817083618. It might be protected by notifiers..
>
> Yeah my thinking is that kvm (and I think also vfio, also seems to
> have mmu notifier nearby) are ok because of the mmu notiifer. Assuming
> that one works correctly.
vfio doesn't have a notifier, Alex was looking to add a vfio private
scheme in the vma->private_data:
https://lore.kernel.org/kvm/159017449210.18853.15037950701494323009.stgit@gimli.home/
Guess it never happened.
> > So, the answer really is that s390 and media need fixing, and this API
> > should go away (or become kvm specific)
>
> I'm still not clear how you want fo fix this, since your vma->dma_buf
> idea is kinda a decade long plan and so just not going to happen:
Well, it doesn't mean we have to change every part of dma_buf to
participate in this. Just the bits media cares about. Or maybe it is
some higher level varient on top of dma_buf.
Or don't use dma_buf for this, add a new object that just provides
refcounts and P2P DMA connection for IO pfn ranges..
Jason
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next prev parent reply other threads:[~2020-10-05 18:39 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-02 17:53 [PATCH 1/2] mm/frame-vec: Drop gup_flags from get_vaddr_frames() Daniel Vetter
2020-10-02 17:53 ` [PATCH 2/2] mm/frame-vec: use FOLL_LONGTERM Daniel Vetter
2020-10-02 18:06 ` Jason Gunthorpe
2020-10-02 18:16 ` Daniel Vetter
2020-10-02 23:31 ` Jason Gunthorpe
2020-10-03 8:34 ` Oded Gabbay
2020-10-03 9:40 ` Daniel Vetter
2020-10-04 12:50 ` Jason Gunthorpe
2020-10-04 16:09 ` Daniel Vetter
2020-10-05 17:28 ` Jason Gunthorpe
2020-10-05 18:16 ` Daniel Vetter
2020-10-05 18:37 ` Jason Gunthorpe [this message]
2020-10-05 18:54 ` Daniel Vetter
2020-10-05 22:43 ` Daniel Vetter
2020-10-05 23:41 ` Jason Gunthorpe
2020-10-06 6:23 ` Daniel Vetter
2020-10-06 12:26 ` Jason Gunthorpe
2020-10-06 13:08 ` Daniel Vetter
2020-10-07 10:47 ` Marek Szyprowski
2020-10-07 12:01 ` Daniel Vetter
2020-10-07 12:33 ` Marek Szyprowski
2020-10-07 12:44 ` Jason Gunthorpe
2020-10-07 12:47 ` Tomasz Figa
2020-10-07 12:58 ` Daniel Vetter
2020-10-07 13:06 ` Jason Gunthorpe
2020-10-07 13:34 ` Tomasz Figa
2020-10-07 13:42 ` Jason Gunthorpe
2020-10-07 14:08 ` Daniel Vetter
2020-10-07 14:11 ` Tomasz Figa
2020-10-07 14:22 ` Daniel Vetter
2020-10-07 15:05 ` Tomasz Figa
2020-10-07 14:58 ` Jason Gunthorpe
2020-10-07 13:06 ` Tomasz Figa
2020-10-07 13:14 ` Jason Gunthorpe
2020-10-05 15:03 ` Jan Kara
2020-10-02 22:39 ` John Hubbard
2020-10-03 9:45 ` Daniel Vetter
2020-10-03 22:52 ` John Hubbard
2020-10-03 23:24 ` Jason Gunthorpe
2020-10-04 11:20 ` Daniel Vetter
2020-10-05 17:35 ` Jason Gunthorpe
2020-10-02 18:22 ` [PATCH 1/2] mm/frame-vec: Drop gup_flags from get_vaddr_frames() Tomasz Figa
2020-10-02 19:21 ` Oded Gabbay
[not found] <0-v1-447bb60c11dd+174-frame_vec_fix_jgg@nvidia.com>
2020-10-05 17:47 ` [PATCH 2/2] mm/frame-vec: use FOLL_LONGTERM Jason Gunthorpe
2020-10-06 3:36 ` Andrew Morton
2020-10-06 11:57 ` Jason Gunthorpe
2020-10-05 17:53 ` Jan Kara
2020-10-05 17:57 ` Jason Gunthorpe
2020-10-05 18:16 ` Daniel Vetter
2020-10-06 11:56 ` Daniel Vetter
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