Re: Xen - i.MX8QM vs i.MX8MQ

[Rajagopal Aravindan <a.rajagopal.81@xxxxxxxxx>]

Hello Peng,

>> Without SMMU, you could not do device passthrough.

Noted, PV driver should still work is my understanding.

>> It will be a bit hard to achieve this. No SMMU, only one GPU.

If running Ubuntu + Android on top of Xen would be hard to achieve on i.MX8MQ, what exactly is the target use case for NXP/CodeAurora port of Xen [1] ?

I do see boards without SMMU listed in Xen wiki project, though [2]  

Thanks,

Rajagopal

[1] - https://source.codeaurora.org/external/imx/imx-xen/

[2] - Xen ARM with Virtualization Extensions - Xen (xenproject.org)

On Mon, Mar 29, 2021 at 3:38 PM Peng Fan <van.freenix@xxxxxxxxx> wrote:

Sorry for HTML format. Inline.

Rajagopal Aravindan <a.rajagopal.81@xxxxxxxxx> 于2021年3月29日周一 下午4:01写道：

Hello Peng,

Thank you for your response.

>>There were people trying to upstream this SoC in community, you should be able to find patches for 8MQ or 8MM.

Will take a look at Xen repo hosted by both LinuxFoundation as well as CodeAurora  and get back.

>>i.MX8MQ could use XEN hypervisor, but note that there is no SMMU in this chip.  

Thanks for highlighting this and at this point in time, I see

1. performance suffering because of this and
2. drivers may need to be modified, to arbitrate access to main memory, between themselves which otherwise SMMU would have taken care of
3. also, drivers need to ensure that they get ONLY those regions in the accessible range to the peripherals

Can you please provide more insight on what the lack of SMMU means to Xen, other than the above ?

Without SMMU, you could not do device passthrough.

 

>> We not see customers requesting xen for i.MX8M*, not sure your usecases.

I do NOT have a i.MX8QM board but ONLY have a i.MX8MQ board and hence was interested in trying Xen on the MQ board. 

Mine is the normal use case of running a Ubuntu + Android on top of Xen, and then running applications inside them.

It will be a bit hard to achieve this. No SMMU, only one GPU.

Regards,

Peng.

 

  

Regards,

Rajagopal

On Mon, Mar 29, 2021 at 8:39 AM Peng Fan <peng.fan@xxxxxxx> wrote:

> Subject: Re: Xen - i.MX8QM vs i.MX8MQ
>
> (+ Peng)

Thanks for adding me.

>
> On 26/03/2021 18:11, Rajagopal Aravindan wrote:
> > Hello All,
>
> Hi,
>
> > Greetings !
> >
> > I came across a few links saying Xen is supported on NXP's i.MX8QM.
> > But, I don't see any such thing for i.MX8MQ and people only talking
> > about jailhouse hypervisor for MQ. [1]
> >
> > Can someone here clarify whether i.MX8MQ h/w is NOT compatible with
> > Xen or the required piece of s/w is yet to be upstreamed to Xen ?

i.MX8MQ could use XEN hypervisor, but note that there is no SMMU in this
chip.

There were people trying to upstream this SoC in community, you should
be able to find patches for 8MQ or 8MM.

We not see customers requesting xen for i.MX8M*, not sure your usecases.

Regards,
Peng.

>
> I have seen users that are successfuly booting Xen on i.MX8, although they are
> not directly using Xen Project tree but one provided by code aurora NXP (see
> [1]).
>
> AFAIK, there might be some missing pieces in the Xen Project tree for that
> board. I am not sure whether this is just to take full of advantage of board.
>
> I have CCed Peng who might be able to provide support.
>
> Cheers,
>
> [1]
> https://eur01.safelinks.protection.outlook.com/?url="">
> .codeaurora.org%2Fexternal%2Fimx%2Fimx-xen%2F&amp;data=""> > Cpeng.fan%40nxp.com%7Cc60e9b08fe0949c6654608d8f0851e15%7C686ea1
> d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637523801815383189%7CUn
> known%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6I
> k1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=7dIXYtfNCOAGNEsVMayTa
> 5ddXkCwewnkLVUMjg4wVt8%3D&amp;reserved=0
>
> --
> Julien Grall

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