From: Federico Vaga <federico.vaga@cern.ch>
To: Vinod Koul <vkoul@kernel.org>
Cc: Dave Jiang <dave.jiang@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
<dmaengine@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: DMA Engine: Transfer From Userspace
Date: Mon, 22 Jun 2020 08:57:27 +0200 [thread overview]
Message-ID: <20200622065727.ywbnevdhjs7kizfc@cwe-513-vol689.cern.ch> (raw)
In-Reply-To: <20200622044733.GB2324254@vkoul-mobl>
On Mon, Jun 22, 2020 at 10:17:33AM +0530, Vinod Koul wrote:
>On 21-06-20, 22:36, Federico Vaga wrote:
>> On Sun, Jun 21, 2020 at 12:54:57PM +0530, Vinod Koul wrote:
>> > On 19-06-20, 16:31, Dave Jiang wrote:
>> > >
>> > >
>> > > On 6/19/2020 3:47 PM, Federico Vaga wrote:
>> > > > Hello,
>> > > >
>> > > > is there the possibility of using a DMA engine channel from userspace?
>> > > >
>> > > > Something like:
>> > > > - configure DMA using ioctl() (or whatever configuration mechanism)
>> > > > - read() or write() to trigger the transfer
>> > > >
>> > >
>> > > I may have supposedly promised Vinod to look into possibly providing
>> > > something like this in the future. But I have not gotten around to do that
>> > > yet. Currently, no such support.
>> >
>> > And I do still have serious reservations about this topic :) Opening up
>> > userspace access to DMA does not sound very great from security point of
>> > view.
>>
>> I was thinking about a dedicated module, and not something that the DMA engine
>> offers directly. You load the module only if you need it (like the test module)
>
>But loading that module would expose dma to userspace.
Of course, but users *should* know what they are doing ... right? ^_^'
>>
>> > Federico, what use case do you have in mind?
>>
>> Userspace drivers
>
>more the reason not do do so, why cant a kernel driver be added for your
>usage?
Yes of course, I was just wandering if there was a kernel API.
>--
>~Vinod
next prev parent reply other threads:[~2020-06-22 6:57 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-19 22:47 DMA Engine: Transfer From Userspace Federico Vaga
2020-06-19 23:31 ` Dave Jiang
2020-06-21 7:24 ` Vinod Koul
2020-06-21 20:36 ` Federico Vaga
2020-06-21 20:45 ` Richard Weinberger
2020-06-21 22:32 ` Federico Vaga
2020-06-22 4:47 ` Vinod Koul
2020-06-22 6:57 ` Federico Vaga [this message]
2020-06-22 12:01 ` Thomas Ruf
2020-06-22 12:27 ` Richard Weinberger
2020-06-22 14:01 ` Thomas Ruf
2020-06-22 12:30 ` Federico Vaga
2020-06-22 14:03 ` Thomas Ruf
2020-06-22 15:54 ` Vinod Koul
2020-06-22 16:34 ` Thomas Ruf
2020-06-24 9:30 ` Thomas Ruf
2020-06-24 9:38 ` Vinod Koul
2020-06-24 12:07 ` Peter Ujfalusi
2020-06-24 13:58 ` Thomas Ruf
2020-06-26 10:29 ` Peter Ujfalusi
2020-06-29 15:18 ` Thomas Ruf
2020-06-30 12:31 ` Peter Ujfalusi
2020-07-01 16:13 ` Thomas Ruf
2020-06-25 0:42 ` Dave Jiang
2020-06-25 8:11 ` Thomas Ruf
2020-06-26 20:08 ` Ira Weiny
2020-06-29 15:31 ` Thomas Ruf
2020-06-22 9:25 ` Federico Vaga
2020-06-22 9:42 ` Vinod Koul
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