From: Ira Weiny <[email protected]> The addition of the DCD support for CXL type-3 devices extended the CDAT table large enough that the checksum being returned was incorrect.[1]
This was because the checksum value was using the header length field rather than each of the 4 bytes of the length field. This was previously not seen because the length of the CDAT data was less than 256 thus resulting in an equivalent checksum value. Properly calculate the checksum for the CDAT header. [1] https://lore.kernel.org/all/[email protected]/ Fixes: aba578bdace5 ("hw/cxl/cdat: CXL CDAT Data Object Exchange implementation") Cc: Huai-Cheng Kuo <[email protected]> Signed-off-by: Ira Weiny <[email protected]> Reviewed-by: Dave Jiang <[email protected]> Reviewed-by: Fan Ni <[email protected]> Signed-off-by: Jonathan Cameron <[email protected]> Message-Id: <[email protected]> Reviewed-by: Michael S. Tsirkin <[email protected]> Signed-off-by: Michael S. Tsirkin <[email protected]> (cherry picked from commit 64fdad5e67587e88c2f1d8f294e89403856a4a31) Signed-off-by: Michael Tokarev <[email protected]> diff --git a/hw/cxl/cxl-cdat.c b/hw/cxl/cxl-cdat.c index 931693f02d..0cde11854e 100644 --- a/hw/cxl/cxl-cdat.c +++ b/hw/cxl/cxl-cdat.c @@ -49,6 +49,7 @@ static void ct3_build_cdat(CDATObject *cdat, Error **errp) g_autofree CDATTableHeader *cdat_header = NULL; g_autofree CDATEntry *cdat_st = NULL; uint8_t sum = 0; + uint8_t *hdr_buf; int ent, i; /* Use default table if fopen == NULL */ @@ -94,8 +95,12 @@ static void ct3_build_cdat(CDATObject *cdat, Error **errp) /* For now, no runtime updates */ cdat_header->sequence = 0; cdat_header->length += sizeof(CDATTableHeader); - sum += cdat_header->revision + cdat_header->sequence + - cdat_header->length; + + hdr_buf = (uint8_t *)cdat_header; + for (i = 0; i < sizeof(*cdat_header); i++) { + sum += hdr_buf[i]; + } + /* Sum of all bytes including checksum must be 0 */ cdat_header->checksum = ~sum + 1; -- 2.39.2
