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

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

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.

From b287ff2c5ee7fbe507ef8cb61df3e4e156a9773f Mon Sep 17 00:00:00 2001
From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Date: Thu, 22 May 2025 14:20:42 +0100
Subject: [PATCH] cxl_test: Limit location for fake CFMWS to mappable range

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 tools/testing/cxl/test/cxl.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
index 8a5815ca870d..b4e6c7659ac4 100644
--- a/tools/testing/cxl/test/cxl.c
+++ b/tools/testing/cxl/test/cxl.c
@@ -1328,6 +1328,7 @@ static int cxl_mem_init(void)
 static __init int cxl_test_init(void)
 {
 	int rc, i;
+	struct range mappable;
 
 	cxl_acpi_test();
 	cxl_core_test();
@@ -1342,8 +1343,11 @@ static __init int cxl_test_init(void)
 		rc = -ENOMEM;
 		goto err_gen_pool_create;
 	}
+	mappable = mhp_get_pluggable_range(true);
 
-	rc = gen_pool_add(cxl_mock_pool, iomem_resource.end + 1 - SZ_64G,
+	rc = gen_pool_add(cxl_mock_pool,
+			  min(iomem_resource.end + 1 - SZ_64G,
+			      mappable.end + 1 - SZ_64G),
 			  SZ_64G, NUMA_NO_NODE);
 	if (rc)
 		goto err_gen_pool_add;
-- 
2.43.0