Any plans to implement more ARM SMMUv3 features?

Any plans to implement more ARM SMMUv3 features?

[Alex Bennée]

Hi All,

Since 8.1 we enabled the FEAT_RME CPU feature to allow for Arm CCA
guests to be run under QEMU's Arm emulation. While this is enough for
pure software guests eventually we would want to support modelling
systems with "real" hardware. One part of that is updating the SMMU
emulation to make it RME aware.

The recently published F.a spec is available on the Arm site:

  https://developer.arm.com/documentation/ihi0070/latest/

As we have a keen interest on tracking (and implementing!) Arm features
we have coded up the various sub-features as stories under an EPIC for
each level of SMMU feature on our public JIRA:

  https://linaro.atlassian.net/browse/QEMU-533 (SMMUv3.0)
  https://linaro.atlassian.net/browse/QEMU-553 (SMMUv3.1)
  https://linaro.atlassian.net/browse/QEMU-558 (SMMUv3.2)
  https://linaro.atlassian.net/browse/QEMU-566 (SMMUv3.3)
  
I think the state of the cards currently represents what has been
implemented and what is left to do. As you can see it adds up to a fair
bit of stuff. As a lot of people have been hacking on the SMMU code over
the last few years I thought it would be useful to reach out and see who
else is interested in further enhancing the SMMU emulation support?

If anyone has any patches/branches cooking or is intending to implement
any particular bits please do let me know and I can update the cards to
reflect the current state of work. As ever we will do our best to help
review and smooth the up-streaming process for all Arm related feature
enhancements.

Thanks,

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro

Re: Any plans to implement more ARM SMMUv3 features?

[Mostafa Saleh]

Hi Alex,

On Tue, Oct 31, 2023 at 12:02:03PM +0000, Alex Bennée wrote:
> 
> Hi All,
> 
> Since 8.1 we enabled the FEAT_RME CPU feature to allow for Arm CCA
> guests to be run under QEMU's Arm emulation. While this is enough for
> pure software guests eventually we would want to support modelling
> systems with "real" hardware. One part of that is updating the SMMU
> emulation to make it RME aware.
> 
> The recently published F.a spec is available on the Arm site:
> 
>   https://developer.arm.com/documentation/ihi0070/latest/
> 
> As we have a keen interest on tracking (and implementing!) Arm features
> we have coded up the various sub-features as stories under an EPIC for
> each level of SMMU feature on our public JIRA:
> 
>   https://linaro.atlassian.net/browse/QEMU-533 (SMMUv3.0)
>   https://linaro.atlassian.net/browse/QEMU-553 (SMMUv3.1)
>   https://linaro.atlassian.net/browse/QEMU-558 (SMMUv3.2)
>   https://linaro.atlassian.net/browse/QEMU-566 (SMMUv3.3)
>   
> I think the state of the cards currently represents what has been
> implemented and what is left to do. As you can see it adds up to a fair
> bit of stuff. As a lot of people have been hacking on the SMMU code over
> the last few years I thought it would be useful to reach out and see who
> else is interested in further enhancing the SMMU emulation support?
> 
> If anyone has any patches/branches cooking or is intending to implement
> any particular bits please do let me know and I can update the cards to
> reflect the current state of work. As ever we will do our best to help
> review and smooth the up-streaming process for all Arm related feature
> enhancements.

I worked on adding stage-2 SMMUv3 support in qemu and was planning on
working on nesting (stage-1 + stage-2). However, I haven't done any
work on this yet and I will be busy till early next year.

If this work would start before that I can put some time to help with
the review, otherwise I can start working on this early next year.

Thanks,
Mostafa

Re: Any plans to implement more ARM SMMUv3 features?

[Eric Auger]

Hi Alex,

On 10/31/23 13:02, Alex Bennée wrote:
> Hi All,
>
> Since 8.1 we enabled the FEAT_RME CPU feature to allow for Arm CCA
> guests to be run under QEMU's Arm emulation. While this is enough for
> pure software guests eventually we would want to support modelling
> systems with "real" hardware. One part of that is updating the SMMU
> emulation to make it RME aware.
>
> The recently published F.a spec is available on the Arm site:
>
>   https://developer.arm.com/documentation/ihi0070/latest/
>
> As we have a keen interest on tracking (and implementing!) Arm features
> we have coded up the various sub-features as stories under an EPIC for
> each level of SMMU feature on our public JIRA:
>
>   https://linaro.atlassian.net/browse/QEMU-533 (SMMUv3.0)
>   https://linaro.atlassian.net/browse/QEMU-553 (SMMUv3.1)
>   https://linaro.atlassian.net/browse/QEMU-558 (SMMUv3.2)
>   https://linaro.atlassian.net/browse/QEMU-566 (SMMUv3.3)
>   
> I think the state of the cards currently represents what has been
> implemented and what is left to do. As you can see it adds up to a fair
> bit of stuff. As a lot of people have been hacking on the SMMU code over
> the last few years I thought it would be useful to reach out and see who
> else is interested in further enhancing the SMMU emulation support?
>
> If anyone has any patches/branches cooking or is intending to implement
> any particular bits please do let me know and I can update the cards to
> reflect the current state of work. As ever we will do our best to help
> review and smooth the up-streaming process for all Arm related feature
> enhancements.

At the moment I have no plan to work on any of those features besides
following "Nested Translation Support for SMMUv3" works ([PATCH v2
00/17] Add Nested Translation Support for SMMUv3
<https://lore.kernel.org/all/cover.1683688960.git.nicolinc@nvidia.com/#r>).
Adding Nicolin in CC by the way.

However I will take some cycles to review patches when they come.

Thanks

Eric
>
> Thanks,
>