iommu/amd: Fix ivrs_acpihid cmdline parsing code

The second (UID) strcmp in acpi_dev_hid_uid_match considers
"0" and "00" different, which can prevent device registration.

Have the AMD IOMMU driver's ivrs_acpihid parsing code remove
any leading zeroes to make the UID strcmp succeed.  Now users
can safely specify "AMDxxxxx:00" or "AMDxxxxx:0" and expect
the same behaviour.

Fixes: ca3bf5d ("iommu/amd: Introduces ivrs_acpihid kernel parameter")
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Cc: stable@vger.kernel.org
Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Cc: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20220919155638.391481-1-kim.phillips@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: kimphillamd

drivers/iommu/amd/init.c

@@ -3488,6 +3488,13 @@ static int __init parse_ivrs_acpihid(char *str)
 		return 1;
 	}
 
+	/*
+	 * Ignore leading zeroes after ':', so e.g., AMDI0095:00
+	 * will match AMDI0095:0 in the second strcmp in acpi_dev_hid_uid_match
+	 */
+	while (*uid == '0' && *(uid + 1))
+		uid++;
+
 	i = early_acpihid_map_size++;
 	memcpy(early_acpihid_map[i].hid, hid, strlen(hid));
 	memcpy(early_acpihid_map[i].uid, uid, strlen(uid));