The offset for the register block should be a 64K aligned value, and
therefore FIELD_GET (which will shift) is not correct for the
calculation.
>From 8.1.9.1 of the CXL 2.0 spec:
A[31:16] of offset from the address contained by one of the Function's
Base Address Registers to point to the base of the Register Block.
Register Block Offset is 64K aligned. Hence A[15:0] is zero
The "Register Offset Low" register of a "DVSEC Register Locator"
contains the 64K aligned offset for the registers along with the BAR
indicator and an ID. The implementation was treating the "Register Block
Offset Low" field a value rather than as a pre-aligned component of the
64-bit offset. So, just mask, don't mask and shift (FIELD_GET).
This wasn't found earlier because the primary development done in the
QEMU environment only uses 0 offsets
Fixes: 8adaf747c9f0 ("cxl/mem: Find device capabilities")
Reported-by: Vishal Verma <[email protected]>
Signed-off-by: Ben Widawsky <[email protected]>
---
drivers/cxl/mem.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index e3003f49b329..1b5078311f7d 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -998,7 +998,7 @@ static struct cxl_mem *cxl_mem_create(struct pci_dev *pdev,
u32 reg_lo,
return NULL;
}
- offset = ((u64)reg_hi << 32) | FIELD_GET(CXL_REGLOC_ADDR_MASK, reg_lo);
+ offset = ((u64)reg_hi << 32) | (reg_lo & CXL_REGLOC_ADDR_MASK);
bar = FIELD_GET(CXL_REGLOC_BIR_MASK, reg_lo);
/* Basic sanity check that BAR is big enough */
--
2.31.1
