[PATCH 1/1] cxl/region: Fix the first aliased address miscalculation

From: Li Ming
Date: Mon Mar 17 2025 - 03:08:06 EST


In extended linear cache(ELC) case, cxl_port_get_spa_cache_alias() helps
to get the aliased address of a SPA, it considers the first address in
CXL memory range is "region start + region cache size + 1", but it
should be "region start + region cache size".

So if a SPA is equal to "region start + region cache size", its aliased
address should be "SPA - region cache size".

Signed-off-by: Li Ming <ming.li@xxxxxxxxxxxx>
---
drivers/cxl/core/region.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 6d8bdb53f258..c3f4dc244df7 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -3460,7 +3460,7 @@ u64 cxl_port_get_spa_cache_alias(struct cxl_port *endpoint, u64 spa)
if (!p->cache_size)
return ~0ULL;

- if (spa > p->res->start + p->cache_size)
+ if (spa >= p->res->start + p->cache_size)
return spa - p->cache_size;

return spa + p->cache_size;
--
2.34.1