Am 24.06.21 um 10:12 schrieb Christoph Hellwig:
On Thu, Jun 24, 2021 at 10:07:14AM +0200, Christian König wrote:
The key point is that accessing the underlying pages even when DMA-bufs are
backed by system memory is illegal. Daniel even created a patch which
mangles the page pointers in sg_table
Am 24.06.21 um 07:34 schrieb Christoph Hellwig:
On Wed, Jun 23, 2021 at 10:00:29PM +0300, Oded Gabbay wrote:
I understand the argument and I agree that for the generic case, the
top of the stack can't assume anything.
Having said that, in this case the SGL is encapsulated inside a dma-buf object
On Wed, Jun 23, 2021 at 10:39:48PM +0300, Oded Gabbay wrote:
> On Wed, Jun 23, 2021 at 10:34 PM Jason Gunthorpe wrote:
> >
> > On Wed, Jun 23, 2021 at 10:00:29PM +0300, Oded Gabbay wrote:
> > > On Wed, Jun 23, 2021 at 9:50 PM Jason Gunthorpe wrote:
> > > >
> > > > On Wed, Jun 23, 2021 at 09:43:04
On Wed, Jun 23, 2021 at 10:34 PM Jason Gunthorpe wrote:
>
> On Wed, Jun 23, 2021 at 10:00:29PM +0300, Oded Gabbay wrote:
> > On Wed, Jun 23, 2021 at 9:50 PM Jason Gunthorpe wrote:
> > >
> > > On Wed, Jun 23, 2021 at 09:43:04PM +0300, Oded Gabbay wrote:
> > >
> > > > Can you please explain why it
On Wed, Jun 23, 2021 at 10:00:29PM +0300, Oded Gabbay wrote:
> On Wed, Jun 23, 2021 at 9:50 PM Jason Gunthorpe wrote:
> >
> > On Wed, Jun 23, 2021 at 09:43:04PM +0300, Oded Gabbay wrote:
> >
> > > Can you please explain why it is so important to (allow) access them
> > > through the CPU ?
> >
> >
On Wed, Jun 23, 2021 at 9:50 PM Jason Gunthorpe wrote:
>
> On Wed, Jun 23, 2021 at 09:43:04PM +0300, Oded Gabbay wrote:
>
> > Can you please explain why it is so important to (allow) access them
> > through the CPU ?
>
> It is not so much important, as it reflects significant design choices
> that
On Wed, Jun 23, 2021 at 09:43:04PM +0300, Oded Gabbay wrote:
> Can you please explain why it is so important to (allow) access them
> through the CPU ?
It is not so much important, as it reflects significant design choices
that are already tightly baked into alot of our stacks.
A SGL is CPU acc
On Wed, Jun 23, 2021 at 9:24 PM Jason Gunthorpe wrote:
>
> On Wed, Jun 23, 2021 at 10:57:35AM +0200, Christian König wrote:
>
> > > > No it isn't. It makes devices depend on allocating struct pages for
> > > > their
> > > > BARs which is not necessary nor desired.
> > > Which dramatically reduces
On Wed, Jun 23, 2021 at 10:57:35AM +0200, Christian König wrote:
> > > No it isn't. It makes devices depend on allocating struct pages for their
> > > BARs which is not necessary nor desired.
> > Which dramatically reduces the cost of establishing DMA mappings, a
> > loop of dma_map_resource() is
On Wed, Jun 23, 2021 at 11:57 AM Christian König
wrote:
>
> Am 22.06.21 um 18:05 schrieb Jason Gunthorpe:
> > On Tue, Jun 22, 2021 at 05:48:10PM +0200, Christian König wrote:
> >> Am 22.06.21 um 17:40 schrieb Jason Gunthorpe:
> >>> On Tue, Jun 22, 2021 at 05:29:01PM +0200, Christian König wrote:
>
Am 22.06.21 um 18:05 schrieb Jason Gunthorpe:
On Tue, Jun 22, 2021 at 05:48:10PM +0200, Christian König wrote:
Am 22.06.21 um 17:40 schrieb Jason Gunthorpe:
On Tue, Jun 22, 2021 at 05:29:01PM +0200, Christian König wrote:
[SNIP]
No absolutely not. NVidia GPUs work exactly the same way.
And yo
Am 2021-06-22 um 11:29 a.m. schrieb Christian König:
> Am 22.06.21 um 17:23 schrieb Jason Gunthorpe:
>> On Tue, Jun 22, 2021 at 02:23:03PM +0200, Christian König wrote:
>>> Am 22.06.21 um 14:01 schrieb Jason Gunthorpe:
On Tue, Jun 22, 2021 at 11:42:27AM +0300, Oded Gabbay wrote:
> On Tue,
On Tue, Jun 22, 2021 at 05:48:10PM +0200, Christian König wrote:
> Am 22.06.21 um 17:40 schrieb Jason Gunthorpe:
> > On Tue, Jun 22, 2021 at 05:29:01PM +0200, Christian König wrote:
> > > [SNIP]
> > > No absolutely not. NVidia GPUs work exactly the same way.
> > >
> > > And you have tons of simila
Am 22.06.21 um 17:40 schrieb Oded Gabbay:
On Tue, Jun 22, 2021 at 6:31 PM Christian König
wrote:
Am 22.06.21 um 17:28 schrieb Jason Gunthorpe:
On Tue, Jun 22, 2021 at 05:24:08PM +0200, Christian König wrote:
I will take two GAUDI devices and use one as an exporter and one as an
importer. I
Am 22.06.21 um 17:40 schrieb Jason Gunthorpe:
On Tue, Jun 22, 2021 at 05:29:01PM +0200, Christian König wrote:
[SNIP]
No absolutely not. NVidia GPUs work exactly the same way.
And you have tons of similar cases in embedded and SoC systems where
intermediate memory between devices isn't directly
On Tue, Jun 22, 2021 at 6:31 PM Christian König
wrote:
>
>
>
> Am 22.06.21 um 17:28 schrieb Jason Gunthorpe:
> > On Tue, Jun 22, 2021 at 05:24:08PM +0200, Christian König wrote:
> >
> I will take two GAUDI devices and use one as an exporter and one as an
> importer. I want to see that th
On Tue, Jun 22, 2021 at 05:29:01PM +0200, Christian König wrote:
> Am 22.06.21 um 17:23 schrieb Jason Gunthorpe:
> > On Tue, Jun 22, 2021 at 02:23:03PM +0200, Christian König wrote:
> > > Am 22.06.21 um 14:01 schrieb Jason Gunthorpe:
> > > > On Tue, Jun 22, 2021 at 11:42:27AM +0300, Oded Gabbay wro
On Tue, Jun 22, 2021 at 06:24:28PM +0300, Oded Gabbay wrote:
> On Tue, Jun 22, 2021 at 6:11 PM Jason Gunthorpe wrote:
> >
> > On Tue, Jun 22, 2021 at 04:12:26PM +0300, Oded Gabbay wrote:
> >
> > > > 1) Setting sg_page to NULL
> > > > 2) 'mapping' pages for P2P DMA without going through the iommu
>
On Tue, Jun 22, 2021 at 6:28 PM Jason Gunthorpe wrote:
>
> On Tue, Jun 22, 2021 at 05:24:08PM +0200, Christian König wrote:
>
> > > > I will take two GAUDI devices and use one as an exporter and one as an
> > > > importer. I want to see that the solution works end-to-end, with real
> > > > device
Am 22.06.21 um 17:28 schrieb Jason Gunthorpe:
On Tue, Jun 22, 2021 at 05:24:08PM +0200, Christian König wrote:
I will take two GAUDI devices and use one as an exporter and one as an
importer. I want to see that the solution works end-to-end, with real
device DMA from importer to exporter.
I
Am 22.06.21 um 17:23 schrieb Jason Gunthorpe:
On Tue, Jun 22, 2021 at 02:23:03PM +0200, Christian König wrote:
Am 22.06.21 um 14:01 schrieb Jason Gunthorpe:
On Tue, Jun 22, 2021 at 11:42:27AM +0300, Oded Gabbay wrote:
On Tue, Jun 22, 2021 at 9:37 AM Christian König
wrote:
Am 22.06.21 um 01:2
On Tue, Jun 22, 2021 at 05:24:08PM +0200, Christian König wrote:
> > > I will take two GAUDI devices and use one as an exporter and one as an
> > > importer. I want to see that the solution works end-to-end, with real
> > > device DMA from importer to exporter.
> > I can tell you it doesn't. Stuff
On Tue, Jun 22, 2021 at 6:11 PM Jason Gunthorpe wrote:
>
> On Tue, Jun 22, 2021 at 04:12:26PM +0300, Oded Gabbay wrote:
>
> > > 1) Setting sg_page to NULL
> > > 2) 'mapping' pages for P2P DMA without going through the iommu
> > > 3) Allowing P2P DMA without using the p2p dma API to validate that i
Am 22.06.21 um 17:11 schrieb Jason Gunthorpe:
On Tue, Jun 22, 2021 at 04:12:26PM +0300, Oded Gabbay wrote:
1) Setting sg_page to NULL
2) 'mapping' pages for P2P DMA without going through the iommu
3) Allowing P2P DMA without using the p2p dma API to validate that it
can work at all in th
On Tue, Jun 22, 2021 at 02:23:03PM +0200, Christian König wrote:
> Am 22.06.21 um 14:01 schrieb Jason Gunthorpe:
> > On Tue, Jun 22, 2021 at 11:42:27AM +0300, Oded Gabbay wrote:
> > > On Tue, Jun 22, 2021 at 9:37 AM Christian König
> > > wrote:
> > > > Am 22.06.21 um 01:29 schrieb Jason Gunthorpe:
On Tue, Jun 22, 2021 at 04:12:26PM +0300, Oded Gabbay wrote:
> > 1) Setting sg_page to NULL
> > 2) 'mapping' pages for P2P DMA without going through the iommu
> > 3) Allowing P2P DMA without using the p2p dma API to validate that it
> >can work at all in the first place.
> >
> > All of these r
On Tue, Jun 22, 2021 at 3:15 PM Jason Gunthorpe wrote:
>
> On Tue, Jun 22, 2021 at 03:04:30PM +0300, Oded Gabbay wrote:
> > On Tue, Jun 22, 2021 at 3:01 PM Jason Gunthorpe wrote:
> > >
> > > On Tue, Jun 22, 2021 at 11:42:27AM +0300, Oded Gabbay wrote:
> > > > On Tue, Jun 22, 2021 at 9:37 AM Chris
Am 22.06.21 um 14:01 schrieb Jason Gunthorpe:
On Tue, Jun 22, 2021 at 11:42:27AM +0300, Oded Gabbay wrote:
On Tue, Jun 22, 2021 at 9:37 AM Christian König
wrote:
Am 22.06.21 um 01:29 schrieb Jason Gunthorpe:
On Mon, Jun 21, 2021 at 10:24:16PM +0300, Oded Gabbay wrote:
Another thing I want t
On Tue, Jun 22, 2021 at 03:04:30PM +0300, Oded Gabbay wrote:
> On Tue, Jun 22, 2021 at 3:01 PM Jason Gunthorpe wrote:
> >
> > On Tue, Jun 22, 2021 at 11:42:27AM +0300, Oded Gabbay wrote:
> > > On Tue, Jun 22, 2021 at 9:37 AM Christian König
> > > wrote:
> > > >
> > > > Am 22.06.21 um 01:29 schrie
On Tue, Jun 22, 2021 at 3:01 PM Jason Gunthorpe wrote:
>
> On Tue, Jun 22, 2021 at 11:42:27AM +0300, Oded Gabbay wrote:
> > On Tue, Jun 22, 2021 at 9:37 AM Christian König
> > wrote:
> > >
> > > Am 22.06.21 um 01:29 schrieb Jason Gunthorpe:
> > > > On Mon, Jun 21, 2021 at 10:24:16PM +0300, Oded G
On Tue, Jun 22, 2021 at 11:42:27AM +0300, Oded Gabbay wrote:
> On Tue, Jun 22, 2021 at 9:37 AM Christian König
> wrote:
> >
> > Am 22.06.21 um 01:29 schrieb Jason Gunthorpe:
> > > On Mon, Jun 21, 2021 at 10:24:16PM +0300, Oded Gabbay wrote:
> > >
> > >> Another thing I want to emphasize is that we
On Tue, Jun 22, 2021 at 9:37 AM Christian König
wrote:
>
> Am 22.06.21 um 01:29 schrieb Jason Gunthorpe:
> > On Mon, Jun 21, 2021 at 10:24:16PM +0300, Oded Gabbay wrote:
> >
> >> Another thing I want to emphasize is that we are doing p2p only
> >> through the export/import of the FD. We do *not* a
Am 22.06.21 um 01:29 schrieb Jason Gunthorpe:
On Mon, Jun 21, 2021 at 10:24:16PM +0300, Oded Gabbay wrote:
Another thing I want to emphasize is that we are doing p2p only
through the export/import of the FD. We do *not* allow the user to
mmap the dma-buf as we do not support direct IO. So there
On Mon, Jun 21, 2021 at 10:24:16PM +0300, Oded Gabbay wrote:
> Another thing I want to emphasize is that we are doing p2p only
> through the export/import of the FD. We do *not* allow the user to
> mmap the dma-buf as we do not support direct IO. So there is no access
> to these pages through the
On Mon, Jun 21, 2021 at 9:27 PM Daniel Vetter wrote:
>
> On Mon, Jun 21, 2021 at 7:55 PM Jason Gunthorpe wrote:
> > On Mon, Jun 21, 2021 at 07:26:14PM +0300, Oded Gabbay wrote:
> > > On Mon, Jun 21, 2021 at 5:12 PM Jason Gunthorpe wrote:
> > > >
> > > > On Mon, Jun 21, 2021 at 03:02:10PM +0200,
On Mon, Jun 21, 2021 at 7:55 PM Jason Gunthorpe wrote:
> On Mon, Jun 21, 2021 at 07:26:14PM +0300, Oded Gabbay wrote:
> > On Mon, Jun 21, 2021 at 5:12 PM Jason Gunthorpe wrote:
> > >
> > > On Mon, Jun 21, 2021 at 03:02:10PM +0200, Greg KH wrote:
> > > > On Mon, Jun 21, 2021 at 02:28:48PM +0200, D
On Mon, Jun 21, 2021 at 07:26:14PM +0300, Oded Gabbay wrote:
> On Mon, Jun 21, 2021 at 5:12 PM Jason Gunthorpe wrote:
> >
> > On Mon, Jun 21, 2021 at 03:02:10PM +0200, Greg KH wrote:
> > > On Mon, Jun 21, 2021 at 02:28:48PM +0200, Daniel Vetter wrote:
> >
> > > > Also I'm wondering which is the ot
On Mon, Jun 21, 2021 at 5:12 PM Jason Gunthorpe wrote:
>
> On Mon, Jun 21, 2021 at 03:02:10PM +0200, Greg KH wrote:
> > On Mon, Jun 21, 2021 at 02:28:48PM +0200, Daniel Vetter wrote:
>
> > > Also I'm wondering which is the other driver that we share buffers
> > > with. The gaudi stuff doesn't have
On Mon, Jun 21, 2021 at 04:20:35PM +0200, Daniel Vetter wrote:
> Also unless we're actually doing this properly there's zero incentive for
> me to review the kernel code and check whether it follows the rules
> correctly, so you have excellent chances that you just break the rules.
> And dma_buf/f
On Mon, Jun 21, 2021 at 03:02:10PM +0200, Greg KH wrote:
> On Mon, Jun 21, 2021 at 02:28:48PM +0200, Daniel Vetter wrote:
> > On Fri, Jun 18, 2021 at 2:36 PM Oded Gabbay wrote:
> > > User process might want to share the device memory with another
> > > driver/device, and to allow it to access it o
On Mon, Jun 21, 2021 at 02:28:48PM +0200, Daniel Vetter wrote:
> Mission acomplished, we've gone full circle, and the totally-not-a-gpu
> driver is now trying to use gpu infrastructure. And seems to have
> gained vram meanwhile too. Next up is going to be synchronization
> using dma_fence so you c
On Mon, Jun 21, 2021 at 03:02:10PM +0200, Greg KH wrote:
> On Mon, Jun 21, 2021 at 02:28:48PM +0200, Daniel Vetter wrote:
> > Also I'm wondering which is the other driver that we share buffers
> > with. The gaudi stuff doesn't have real struct pages as backing
> > storage, it only fills out the dm
On Mon, Jun 21, 2021 at 02:28:48PM +0200, Daniel Vetter wrote:
> On Fri, Jun 18, 2021 at 2:36 PM Oded Gabbay wrote:
> > User process might want to share the device memory with another
> > driver/device, and to allow it to access it over PCIe (P2P).
> >
> > To enable this, we utilize the dma-buf me
On Fri, Jun 18, 2021 at 2:36 PM Oded Gabbay wrote:
> User process might want to share the device memory with another
> driver/device, and to allow it to access it over PCIe (P2P).
>
> To enable this, we utilize the dma-buf mechanism and add a dma-buf
> exporter support, so the other driver can imp
User process might want to share the device memory with another
driver/device, and to allow it to access it over PCIe (P2P).
To enable this, we utilize the dma-buf mechanism and add a dma-buf
exporter support, so the other driver can import the device memory and
access it.
The device memory is al
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