From: Jason Gunthorpe <jgg@nvidia.com>
To: Oded Gabbay <ogabbay@kernel.org>
Cc: "moderated list:DMA BUFFER SHARING FRAMEWORK"
<linaro-mm-sig@lists.linaro.org>,
"Leon Romanovsky" <leon@kernel.org>,
"KVM list" <kvm@vger.kernel.org>,
linux-rdma <linux-rdma@vger.kernel.org>,
"Daniel Vetter" <daniel.vetter@ffwll.ch>,
"Cornelia Huck" <cohuck@redhat.com>,
"Maling list - DRI developers" <dri-devel@lists.freedesktop.org>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Christoph Hellwig" <hch@infradead.org>,
"Alex Williamson" <alex.williamson@redhat.com>,
"Maor Gottlieb" <maorg@nvidia.com>,
"Christian König" <christian.koenig@amd.com>,
"Linux Media Mailing List" <linux-media@vger.kernel.org>
Subject: Re: [PATCH v2 4/4] vfio/pci: Allow MMIO regions to be exported through dma-buf
Date: Tue, 6 Sep 2022 14:59:11 -0300 [thread overview]
Message-ID: <YxeKb9qxFXodg832@nvidia.com> (raw)
In-Reply-To: <CAFCwf115rwTWzgPXcpog4u5NAvH4JO+Qis_fcx0mRrNR5AQcaQ@mail.gmail.com>
On Tue, Sep 06, 2022 at 03:34:02PM +0300, Oded Gabbay wrote:
> > > > > + /*
> > > > > + * Since the memory being mapped is a device memory it could never be in
> > > > > + * CPU caches.
> > > > > + */
> > > > DMA_ATTR_SKIP_CPU_SYNC doesn't even apply to dma_map_resource, not sure
> > > > where this wisdom comes from.
> >
> > Habana driver
> I hate to throw the ball at someone else, but I actually copied the
> code from the amdgpu driver, from amdgpu_vram_mgr_alloc_sgt() iirc.
> And if you remember Jason, you asked why we use this specific define
> in the original review you did and I replied the following (to which
> you agreed and that's why we added the comment):
Yes, I remember, but Christophs remark is that DMA_ATTR_SKIP_CPU_SYNC
doesn't even do anything when passed to dma_map_resource().
The only attr that seems to be used is DMA_ATTR_PRIVILEGED from what I
can see.
Jason
next prev parent reply other threads:[~2022-09-06 17:59 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-31 23:12 [PATCH v2 0/4] Allow MMIO regions to be exported through dma-buf Jason Gunthorpe
2022-08-31 23:12 ` [PATCH v2 1/4] dma-buf: Add dma_buf_try_get() Jason Gunthorpe
2022-09-01 7:55 ` Christian König
2022-09-06 16:44 ` Jason Gunthorpe
2022-09-06 17:52 ` Christian König
2022-08-31 23:12 ` [PATCH v2 2/4] vfio: Add vfio_device_get() Jason Gunthorpe
2022-08-31 23:12 ` [PATCH v2 3/4] vfio_pci: Do not open code pci_try_reset_function() Jason Gunthorpe
2022-08-31 23:12 ` [PATCH v2 4/4] vfio/pci: Allow MMIO regions to be exported through dma-buf Jason Gunthorpe
[not found] ` <YxcYGzPv022G2vLm@infradead.org>
2022-09-06 10:38 ` Christian König
2022-09-06 11:48 ` Jason Gunthorpe
2022-09-06 12:34 ` Oded Gabbay
2022-09-06 17:59 ` Jason Gunthorpe [this message]
2022-09-06 19:44 ` Oded Gabbay
[not found] ` <YxiJJYtWgh1l0wxg@infradead.org>
2022-09-07 12:33 ` Jason Gunthorpe
[not found] ` <Yxiq5sjf/qA7xS8A@infradead.org>
2022-09-07 14:46 ` Oded Gabbay
2022-09-07 15:23 ` Jason Gunthorpe
[not found] ` <Yxi5h09JAzIo4Kh8@infradead.org>
2022-09-07 16:12 ` Jason Gunthorpe
[not found] ` <Yxs+k6psNfBLDqdv@infradead.org>
2022-09-09 14:09 ` Jason Gunthorpe
2022-09-07 16:31 ` Robin Murphy
2022-09-07 16:47 ` Jason Gunthorpe
2022-09-07 17:03 ` Dan Williams
2022-09-07 15:01 ` Robin Murphy
[not found] ` <YxiIkh/yeWQkZ54x@infradead.org>
2022-09-07 15:08 ` Christian König
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