dmaengine Archive on lore.kernel.org
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From: Dave Jiang <dave.jiang@intel.com>
To: Vinod Koul <vkoul@kernel.org>
Cc: Federico Vaga <federico.vaga@cern.ch>,
	Dan Williams <dan.j.williams@intel.com>,
	dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, "Kumar,
	Sanjay K" <sanjay.k.kumar@intel.com>,
	"Luck, Tony" <tony.luck@intel.com>
Subject: Re: DMA Engine: Transfer From Userspace
Date: Wed, 24 Jun 2020 17:42:24 -0700
Message-ID: <581f1761-e582-c770-169a-ee3374baf25c@intel.com> (raw)
In-Reply-To: <20200621072457.GA2324254@vkoul-mobl>



On 6/21/2020 12:24 AM, 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.

What about doing it with DMA engine that supports PASID? That way the user can 
really only trash its own address space and kernel is protected.


> 
> Federico, what use case do you have in mind?
> 
> We should keep in mind dmaengine is an in-kernel interface providing
> services to various subsystems, so you go thru the respective subsystem
> kernel interface (network, display, spi, audio etc..) which would in
> turn use dmaengine.
> 

  parent reply index

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-19 22:47 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
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 [this message]
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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