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Re: [PATCH v2 8/8] xen/arm: Add support for SMMUv3 driver


  • To: Julien Grall <julien@xxxxxxx>
  • From: Rahul Singh <Rahul.Singh@xxxxxxx>
  • Date: Wed, 9 Dec 2020 18:37:08 +0000
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  • Cc: Bertrand Marquis <Bertrand.Marquis@xxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, George Dunlap <george.dunlap@xxxxxxxxxx>, Ian Jackson <iwj@xxxxxxxxxxxxxx>, Jan Beulich <jbeulich@xxxxxxxx>, Wei Liu <wl@xxxxxxx>, Paul Durrant <paul@xxxxxxx>, Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
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  • Thread-topic: [PATCH v2 8/8] xen/arm: Add support for SMMUv3 driver

Hello Julien,

> On 9 Dec 2020, at 9:18 am, Julien Grall <julien@xxxxxxx> wrote:
> 
> 
> 
> On 09/12/2020 07:55, Bertrand Marquis wrote:
>> Hi,
> 
> Hi,
> 
>> I also agree with the issue on the spinlock but we have no equivalent of 
>> something
>> looking like a mutex for now in Xen so this would require some major 
>> redesign and
>> will take us far from the linux driver.
> 
> I agree that keeping the Xen implementation close to the Linux one is 
> important. However, I view this has a the secondary goal. The primary goal is 
> to have a safe and secure driver.
> 
> If it means introducing a new set of lock or diverging from Linux, then so it 
> be.
>> I would suggest to add a comment before this part of the code with a “TODO” 
>> so that
>> it is clear inside the code.
>> We could also add some comment in Kconfig to mention this possible “faulty” 
>> behaviour.
> 
> I think it would be enough to write in the Kconfig that the driver is 
> "experimental and should not be used in production”.

Ok . I will add in Kconfig.
> 
> Ideally, I would like a list of known issues for the driver (could be in the 
> cover letter or/and at the top of the source file) so we can track what's 
> missing to get it supported.

I will list all known issues and short coming of the driver at the top of the 
source file.

Regards,
Rahul
> 
> Cheers,
> 
> -- 
> Julien Grall


 


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