From: Ira Weiny <ira.weiny@intel.com>
To: Thomas Ruf <freelancer@rufusul.de>
Cc: Dave Jiang <dave.jiang@intel.com>, Vinod Koul <vkoul@kernel.org>,
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: Fri, 26 Jun 2020 13:08:15 -0700 [thread overview]
Message-ID: <20200626200815.GC2454695@iweiny-DESK2.sc.intel.com> (raw)
In-Reply-To: <84270660.632865.1593072688966@mailbusiness.ionos.de>
On Thu, Jun 25, 2020 at 10:11:28AM +0200, Thomas Ruf wrote:
>
> > On 25 June 2020 at 02:42 Dave Jiang <dave.jiang@intel.com> wrote:
> >
> >
> >
> >
> > 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.
>
> Sounds interesting! Not sure if this is really needed in that case...
> I have already implemented checks of vm_area_struct for contiguous memory or even do a get_user_pages_fast for user memory to pin it (hope that is the correct term here). Of course i have to do that for every involved page.
FWIW there is a new pin_user_pages_fast()/unpin_user_page() interface now.
Ira
> But i will do some checks if my code is really suitable to avoid misusage.
>
> Best regards,
> Thomas
next prev parent reply other threads:[~2020-06-26 20:08 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
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 [this message]
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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