From: Florian Fainelli <f.fainelli@gmail.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: heikki.krogerus@linux.intel.com, peterz@infradead.org,
benh@kernel.crashing.org, grant.likely@arm.com, paulus@samba.org,
Frank Rowand <frowand.list@gmail.com>,
mingo@kernel.org, sstabellini@kernel.org,
Saravana Kannan <saravanak@google.com>,
xypron.glpk@gmx.de, rafael.j.wysocki@intel.com,
Christoph Hellwig <hch@lst.de>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
xen-devel@lists.xenproject.org,
Thierry Reding <treding@nvidia.com>,
linux-devicetree <devicetree@vger.kernel.org>,
will@kernel.org, dan.j.williams@intel.com,
linuxppc-dev@lists.ozlabs.org, Rob Herring <robh+dt@kernel.org>,
Claire Chang <tientzu@chromium.org>,
boris.ostrovsky@oracle.com,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
jgross@suse.com, Nicolas Boichat <drinkcat@chromium.org>,
Greg KH <gregkh@linuxfoundation.org>,
rdunlap@infradead.org, lkml <linux-kernel@vger.kernel.org>,
"list@263.net:IOMMU DRIVERS" <iommu@lists.linux-foundation.org>,
mpe@ellerman.id.au, Robin Murphy <robin.murphy@arm.com>
Subject: Re: [RFC PATCH v3 2/6] swiotlb: Add restricted DMA pool
Date: Tue, 12 Jan 2021 15:52:16 -0800 [thread overview]
Message-ID: <bb25fac5-94ee-ff61-9afb-0024b5047f94@gmail.com> (raw)
In-Reply-To: <20210107211937.GA19460@char.us.oracle.com>
On 1/7/21 1:19 PM, Konrad Rzeszutek Wilk wrote:
> On Thu, Jan 07, 2021 at 10:09:14AM -0800, Florian Fainelli wrote:
>> On 1/7/21 9:57 AM, Konrad Rzeszutek Wilk wrote:
>>> On Fri, Jan 08, 2021 at 01:39:18AM +0800, Claire Chang wrote:
>>>> Hi Greg and Konrad,
>>>>
>>>> This change is intended to be non-arch specific. Any arch that lacks DMA access
>>>> control and has devices not behind an IOMMU can make use of it. Could you share
>>>> why you think this should be arch specific?
>>>
>>> The idea behind non-arch specific code is it to be generic. The devicetree
>>> is specific to PowerPC, Sparc, and ARM, and not to x86 - hence it should
>>> be in arch specific code.
>>
>> In premise the same code could be used with an ACPI enabled system with
>> an appropriate service to identify the restricted DMA regions and unlock
>> them.
>
> Which this patchset is not.
ACPI is not included, but the comment about Device Tree being specific
to PowerPC, SPARC and ARM is x86 is not quite correct. There is an
architecture specific part to obtaining where the Device Tree lives in
memory, but the implementation itself is architecture agnostic (with
some early SPARC/OpenFirmware shenanigans), and x86 does, or rather did
support Device Tree to a very small extent with the CE4100 platform.
Would you prefer that an swiotlb_of.c file be created instead or
something along those lines to better encapsulate where the OF specific
code lives?
>
>>
>> More than 1 architecture requiring this function (ARM and ARM64 are the
>> two I can think of needing this immediately) sort of calls for making
>> the code architecture agnostic since past 2, you need something that scales.
>
> I believe the use-case is for ARM64 at this moment.
For the platforms that Claire uses, certainly for the ones we use, ARM
and ARM64 are in scope.
--
Florian
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next prev parent reply other threads:[~2021-01-12 23:52 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-06 3:41 [RFC PATCH v3 0/6] Restricted DMA Claire Chang
2021-01-06 3:41 ` [RFC PATCH v3 1/6] swiotlb: Add io_tlb_mem struct Claire Chang
2021-01-13 11:50 ` Christoph Hellwig
2021-01-06 3:41 ` [RFC PATCH v3 2/6] swiotlb: Add restricted DMA pool Claire Chang
2021-01-06 7:50 ` Greg KH
2021-01-13 11:51 ` Christoph Hellwig
2021-01-13 12:29 ` Greg KH
2021-01-13 12:37 ` Christoph Hellwig
2021-01-06 18:52 ` Konrad Rzeszutek Wilk
2021-01-07 17:39 ` Claire Chang
2021-01-07 17:57 ` Konrad Rzeszutek Wilk
2021-01-07 18:09 ` Florian Fainelli
2021-01-07 21:19 ` Konrad Rzeszutek Wilk
2021-01-12 23:52 ` Florian Fainelli [this message]
2021-01-25 5:26 ` Jon Masters
2021-01-13 1:53 ` Robin Murphy
2021-01-13 0:03 ` Florian Fainelli
2021-01-13 13:59 ` Nicolas Saenz Julienne
2021-01-13 15:27 ` Robin Murphy
2021-01-13 17:43 ` Florian Fainelli
2021-01-13 18:03 ` Robin Murphy
2021-01-13 12:42 ` Christoph Hellwig
2021-01-14 9:06 ` Claire Chang
2021-01-06 3:41 ` [RFC PATCH v3 3/6] swiotlb: Use restricted DMA pool if available Claire Chang
2021-01-12 23:39 ` Florian Fainelli
2021-01-13 12:44 ` Christoph Hellwig
2021-01-06 3:41 ` [RFC PATCH v3 4/6] swiotlb: Add restricted DMA alloc/free support Claire Chang
2021-01-12 23:41 ` Florian Fainelli
2021-01-13 12:48 ` Christoph Hellwig
2021-01-13 18:27 ` Robin Murphy
2021-01-13 18:32 ` Christoph Hellwig
2021-01-06 3:41 ` [RFC PATCH v3 5/6] dt-bindings: of: Add restricted DMA pool Claire Chang
2021-01-06 18:57 ` Konrad Rzeszutek Wilk
2021-01-07 17:39 ` Claire Chang
2021-01-07 18:00 ` Konrad Rzeszutek Wilk
2021-01-07 18:14 ` Florian Fainelli
2021-01-12 7:47 ` Claire Chang
2021-01-20 16:53 ` Rob Herring
2021-01-20 17:30 ` Robin Murphy
2021-01-20 21:31 ` Rob Herring
2021-01-21 1:09 ` Robin Murphy
2021-01-21 15:48 ` Rob Herring
2021-01-21 17:29 ` Robin Murphy
2021-01-06 3:41 ` [RFC PATCH v3 6/6] of: Add plumbing for " Claire Chang
2021-01-12 23:48 ` Florian Fainelli
2021-01-14 9:08 ` Claire Chang
2021-01-14 18:52 ` Florian Fainelli
2021-01-15 3:46 ` Claire Chang
2021-01-06 18:48 ` [RFC PATCH v3 0/6] Restricted DMA Florian Fainelli
2021-01-07 17:38 ` Claire Chang
2021-01-07 17:42 ` Claire Chang
2021-01-07 17:59 ` Florian Fainelli
2021-01-12 7:48 ` Claire Chang
2021-01-12 18:01 ` Florian Fainelli
2021-01-13 2:29 ` Tomasz Figa
2021-01-13 3:56 ` Florian Fainelli
2021-01-13 4:25 ` Tomasz Figa
2021-01-13 4:41 ` Florian Fainelli
2021-02-09 6:27 ` Claire Chang
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