Re: [BUG] cxl can not create region

[Bobo WL]

Hi Jonathan

Thanks for your reply!

On Mon, Aug 8, 2022 at 8:37 PM Jonathan Cameron
<Jonathan.Cameron@huawei.com> wrote:
>
> Probably not related to your problem, but there is a disconnect in QEMU /
> kernel assumptionsaround the presence of an HDM decoder when a HB only
> has a single root port. Spec allows it to be provided or not as an 
> implementation choice.
> Kernel assumes it isn't provide. Qemu assumes it is.
>
> The temporary solution is to throw in a second root port on the HB and not
> connect anything to it.  Longer term I may special case this so that the 
> particular
> decoder defaults to pass through settings in QEMU if there is only one root 
> port.
>

You are right! After adding an extra HB in qemu, I can create a x1
region successfully.
But have some errors in Nvdimm:

[   74.925838] Unknown online node for memory at 0x10000000000, assuming node 0
[   74.925846] Unknown target node for memory at 0x10000000000, assuming node 0
[   74.927470] nd_region region0: nmem0: is disabled, failing probe

And x4 region still failed with same errors, using latest cxl/preview
branch don't work.
I have picked "Two CXL emulation fixes" patches in qemu, still not working.

Bob