Re: ndctl cxl test suite fails in arm64 QEMU

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Fri, 7 Mar 2025 10:44:23 +0900
Itaru Kitayama <itaru.kitayama@linux.dev> wrote:

> Hi Jonathan, Alison,
> 
> > On Feb 28, 2025, at 23:34, Itaru Kitayama <itaru.kitayama@linux.dev> wrote:
> > 
> > On Tue, Feb 25, 2025 at 02:40:25PM -0800, Alison Schofield wrote:  
> >> On Tue, Feb 25, 2025 at 01:09:57PM +0900, Itaru Kitayama wrote:  
> >>> Hi,
> >>> 
> >>> Has anyone noticed the ndctl cxl test suite failures I reported below on arm64, QEMU emulation?
> >>> 
> >>> https://github.com/pmem/ndctl/issues/278
> >>> 
> >>> I’m using Jonathan’s latest CXL capable QEMU [1], and the latest CXL kernel [2].  
> >> 
> >> Hi Itaru,
> >> 
> >> Looking at region.c:size_store() it seems that alloc_hpa() is failing.
> >> (kstrtou64 is arch independent and it works for me with same script &
> >> value)
> >> 
> >> Check the dmesg log at the time of the failure. alloc_hpa() may be
> >> emitting a message.  (In the run_qemu.sh cmdline add '--cxl-debug')  
> > 
> > dynamic debug reported this (kernel is without kaslr, today's cxl/next):
> > 
> > [  193.267649] device: 'region4': device_add
> > [  193.267931] bus: 'cxl': add device region4
> > [  193.268284] cxl region4: bus: 'cxl': __driver_probe_device: matched device with driver cxl_region
> > [  193.268333] cxl region4: bus: 'cxl': really_probe: probing driver cxl_region with device
> > [  193.268401] cxl_region region4: no default pinctrl state
> > [  193.268482] cxl_region region4: probe with driver cxl_region rejects match -6
> > 
> > does the above show the region4 was not added properly? The sysfs
> > entries are there after the out of range failure.  
> 
> The driver/cxl/core/region.c’s size_store() triggers a sequence of: 
> 
> alloc_hpa()
> alloc_free_mem_region()
> get_free_mem_region() // with flags set to 0, retruns -ERANGE
> 
> While I am looking at the resource core code, do you think this is caused by the old firmware I am using
> when booting QEMU built off of your CXL topic branch? Suggestions are welcome.
Unlikely as I don't think there have been any relevant changes in edk2 for
a long long time.

Jonathan

> 
> Itaru. 
> 
> > 
> > Itaru.
> >   
> >> 
> >> Sounds like Marc is on to something and maybe the KASLR is known
> >> to cause this problem.
> >> 
> >> Thanks for posting to this list and send any further questions or
> >> comments. Happy to have you using run_qemu.sh and the cxl tests!
> >> 
> >> Alison
> >> 
> >>   
> >>> 
> >>> [1] https://gitlab.com/jic23/qemu/ cxl-2025-02-20
> >>> [2] https://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl.git/
> >>> 
> >>> Thanks,
> >>> Itaru.  
> 
> 
>