Re: Internal error: Oops: 0000000096000044 [#11] SMP

[Dan Williams <dan.j.williams@intel.com>]

Jonathan Cameron wrote:
> On Wed, 21 May 2025 16:34:16 -0700
> Dan Williams <dan.j.williams@intel.com> wrote:
> 
> > Itaru Kitayama wrote:
> > > Dave et al.,  
> > [..]
> > > Rebuilt the rootfs image and tried today’s cx/next
> > > (6.15.0-rc4-00046-g6eed708a5693) again to boot now I don’t see the
> > > splats, so something I was messing my dev environment sorry about
> > > that.
> > > 
> > > CXL utility commands work reasonably now and I can execute meson test
> > > —suite cxl, while most of them still fails due to the HPA allocation
> > > error which makes me wonder as the resource requests are quite modest.   
> > 
> > So cxl_test_init() just "hopes" that the top of the system physical
> > address space is free to use to emulate CXL windows. That might be an
> > assumption that only works for x86_64, not ARM64. I would double check
> > that this code in cxl_test_init()
> > 
> >         rc = gen_pool_add(cxl_mock_pool, iomem_resource.end + 1 - SZ_64G,
> >                           SZ_64G, NUMA_NO_NODE);
> >         if (rc)
> >                 goto err_gen_pool_add;
> > 
> > ...is not setting up CXL Windows that overlap with existing resources in
> > that range.
> > 
> 
> I think there are checks that block use of ranges up there.
> 
> Print I'm seeing is
> Hotplug memory [0xfffffff010000000-0xfffffff030000000] exceeds maximum addressable range [0x40000000-0xf80003fffffff]
> 
> I think right answer is to use mhp_get_pluggable_range(true); to check
> for limits on the range we can use.
> 
> On architectures that don't define arch_get_mappable_range()
> that ends up the as (unsigned long)-1 which I think would work
> though there may be other stuff up there.  Maybe min(iomem_resource.end + 1 - SZ_64G,
> 						     mappable_range.end + 1 - SZ_64G)
> or something like that adapted to avoid wrap around.
> 
> I haven't yet sanity checked this doesn't break x86 but I think it should
> end up making no difference to the locations on x86.
> 
> 
> With the below - all 11 tests in ndctl cxl test suite pass for me.

It was whitespace clobbered but after fixing that up and adding #include
<linux/memory_hotplug.h>, it works here, thanks!

Reviewed-by: Dan Williams <dan.j.williams@intel.com>