EINJ, CXL: Fix CXL device SBDF calculation

[ Upstream commit ee1e3c46ed19c096be22472c728fa7f68b1352c4 ]

The SBDF of the target CXL 2.0 compliant root port is required to inject a CXL
protocol error as per ACPI 6.5. The SBDF given has to be in the
following format:

31     24 23    16 15    11 10      8  7        0
+-------------------------------------------------+
| segment |   bus  | device | function | reserved |
+-------------------------------------------------+

The SBDF calculated in cxl_dport_get_sbdf() doesn't account for
the reserved bits currently, causing the wrong SBDF to be used.
Fix said calculation to properly shift the SBDF.

Without this fix, error injection into CXL 2.0 root ports through the
CXL debugfs interface (<debugfs>/cxl) is broken. Injection
through the legacy interface (<debugfs>/apei/einj/) will still work
because the SBDF is manually provided by the user.

Fixes: 12fb28ea6b1cf ("EINJ: Add CXL error type support")
Signed-off-by: Ben Cheatham <Benjamin.Cheatham@amd.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
Reviewed-by: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
Link: https://patch.msgid.link/20240927163428.366557-1-Benjamin.Cheatham@amd.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/acpi/apei/einj-cxl.c b/drivers/acpi/apei/einj-cxl.c
index 8b8be0c90709f9d1db974f9cbdd6c8f765d3d667..d64e2713aae4bf1e9d4d54c441ef4e74b0e65598 100644 (file)
--- a/drivers/acpi/apei/einj-cxl.c
+++ b/drivers/acpi/apei/einj-cxl.c
@@ -63,7 +63,7 @@ static int cxl_dport_get_sbdf(struct pci_dev *dport_dev, u64 *sbdf)
                seg = bridge->domain_nr;
 
        bus = pbus->number;
-       *sbdf = (seg << 24) | (bus << 16) | dport_dev->devfn;
+       *sbdf = (seg << 24) | (bus << 16) | (dport_dev->devfn << 8);
 
        return 0;
 }