iommu/amd: Fix ill-formed ivrs_ioapic, ivrs_hpet and ivrs_acpihid options

Currently, these options cause the following libkmod error:

libkmod: ERROR ../libkmod/libkmod-config.c:489 kcmdline_parse_result: \
	Ignoring bad option on kernel command line while parsing module \
	name: 'ivrs_xxxx[XX:XX'

Fix by introducing a new parameter format for these options and
throw a warning for the deprecated format.

Users are still allowed to omit the PCI Segment if zero.

Adding a Link: to the reason why we're modding the syntax parsing
in the driver and not in libkmod.

Fixes: ca3bf5d ("iommu/amd: Introduces ivrs_acpihid kernel parameter")
Cc: [email protected]
Link: https://lore.kernel.org/linux-modules/[email protected]/
Reported-by: Kim Phillips <[email protected]>
Co-developed-by: Suravee Suthikulpanit <[email protected]>
Signed-off-by: Suravee Suthikulpanit <[email protected]>
Signed-off-by: Kim Phillips <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>

Author: kimphillamd

Documentation/admin-guide/kernel-parameters.txt

@@ -2300,7 +2300,13 @@
 			Provide an override to the IOAPIC-ID<->DEVICE-ID
 			mapping provided in the IVRS ACPI table.
 			By default, PCI segment is 0, and can be omitted.
-			For example:
+
+			For example, to map IOAPIC-ID decimal 10 to
+			PCI segment 0x1 and PCI device 00:14.0,
+			write the parameter as:
+				ivrs_ioapic=10@0001:00:14.0
+
+			Deprecated formats:
 			* To map IOAPIC-ID decimal 10 to PCI device 00:14.0
 			  write the parameter as:
 				ivrs_ioapic[10]=00:14.0
@@ -2312,7 +2318,13 @@
 			Provide an override to the HPET-ID<->DEVICE-ID
 			mapping provided in the IVRS ACPI table.
 			By default, PCI segment is 0, and can be omitted.
-			For example:
+
+			For example, to map HPET-ID decimal 10 to
+			PCI segment 0x1 and PCI device 00:14.0,
+			write the parameter as:
+				ivrs_hpet=10@0001:00:14.0
+
+			Deprecated formats:
 			* To map HPET-ID decimal 0 to PCI device 00:14.0
 			  write the parameter as:
 				ivrs_hpet[0]=00:14.0
@@ -2323,15 +2335,20 @@
 	ivrs_acpihid	[HW,X86-64]
 			Provide an override to the ACPI-HID:UID<->DEVICE-ID
 			mapping provided in the IVRS ACPI table.
+			By default, PCI segment is 0, and can be omitted.
 
 			For example, to map UART-HID:UID AMD0020:0 to
 			PCI segment 0x1 and PCI device ID 00:14.5,
 			write the parameter as:
-				ivrs_acpihid[0001:00:14.5]=AMD0020:0
+				ivrs_acpihid=AMD0020:0@0001:00:14.5
 
-			By default, PCI segment is 0, and can be omitted.
-			For example, PCI device 00:14.5 write the parameter as:
+			Deprecated formats:
+			* To map UART-HID:UID AMD0020:0 to PCI segment is 0,
+			  PCI device ID 00:14.5, write the parameter as:
 				ivrs_acpihid[00:14.5]=AMD0020:0
+			* To map UART-HID:UID AMD0020:0 to PCI segment 0x1 and
+			  PCI device ID 00:14.5, write the parameter as:
+				ivrs_acpihid[0001:00:14.5]=AMD0020:0
 
 	js=		[HW,JOY] Analog joystick
 			See Documentation/input/joydev/joystick.rst.

drivers/iommu/amd/init.c

@@ -3402,18 +3402,24 @@ static int __init parse_amd_iommu_options(char *str)
 static int __init parse_ivrs_ioapic(char *str)
 {
 	u32 seg = 0, bus, dev, fn;
-	int ret, id, i;
+	int id, i;
 	u32 devid;
 
-	ret = sscanf(str, "[%d]=%x:%x.%x", &id, &bus, &dev, &fn);
-	if (ret != 4) {
-		ret = sscanf(str, "[%d]=%x:%x:%x.%x", &id, &seg, &bus, &dev, &fn);
-		if (ret != 5) {
-			pr_err("Invalid command line: ivrs_ioapic%s\n", str);
-			return 1;
-		}
+	if (sscanf(str, "=%d@%x:%x.%x", &id, &bus, &dev, &fn) == 4 ||
+	    sscanf(str, "=%d@%x:%x:%x.%x", &id, &seg, &bus, &dev, &fn) == 5)
+		goto found;
+
+	if (sscanf(str, "[%d]=%x:%x.%x", &id, &bus, &dev, &fn) == 4 ||
+	    sscanf(str, "[%d]=%x:%x:%x.%x", &id, &seg, &bus, &dev, &fn) == 5) {
+		pr_warn("ivrs_ioapic%s option format deprecated; use ivrs_ioapic=%d@%04x:%02x:%02x.%d instead\n",
+			str, id, seg, bus, dev, fn);
+		goto found;
 	}
 
+	pr_err("Invalid command line: ivrs_ioapic%s\n", str);
+	return 1;
+
+found:
 	if (early_ioapic_map_size == EARLY_MAP_SIZE) {
 		pr_err("Early IOAPIC map overflow - ignoring ivrs_ioapic%s\n",
 			str);
@@ -3434,18 +3440,24 @@ static int __init parse_ivrs_ioapic(char *str)
 static int __init parse_ivrs_hpet(char *str)
 {
 	u32 seg = 0, bus, dev, fn;
-	int ret, id, i;
+	int id, i;
 	u32 devid;
 
-	ret = sscanf(str, "[%d]=%x:%x.%x", &id, &bus, &dev, &fn);
-	if (ret != 4) {
-		ret = sscanf(str, "[%d]=%x:%x:%x.%x", &id, &seg, &bus, &dev, &fn);
-		if (ret != 5) {
-			pr_err("Invalid command line: ivrs_hpet%s\n", str);
-			return 1;
-		}
+	if (sscanf(str, "=%d@%x:%x.%x", &id, &bus, &dev, &fn) == 4 ||
+	    sscanf(str, "=%d@%x:%x:%x.%x", &id, &seg, &bus, &dev, &fn) == 5)
+		goto found;
+
+	if (sscanf(str, "[%d]=%x:%x.%x", &id, &bus, &dev, &fn) == 4 ||
+	    sscanf(str, "[%d]=%x:%x:%x.%x", &id, &seg, &bus, &dev, &fn) == 5) {
+		pr_warn("ivrs_hpet%s option format deprecated; use ivrs_hpet=%d@%04x:%02x:%02x.%d instead\n",
+			str, id, seg, bus, dev, fn);
+		goto found;
 	}
 
+	pr_err("Invalid command line: ivrs_hpet%s\n", str);
+	return 1;
+
+found:
 	if (early_hpet_map_size == EARLY_MAP_SIZE) {
 		pr_err("Early HPET map overflow - ignoring ivrs_hpet%s\n",
 			str);
@@ -3466,19 +3478,36 @@ static int __init parse_ivrs_hpet(char *str)
 static int __init parse_ivrs_acpihid(char *str)
 {
 	u32 seg = 0, bus, dev, fn;
-	char *hid, *uid, *p;
+	char *hid, *uid, *p, *addr;
 	char acpiid[ACPIHID_UID_LEN + ACPIHID_HID_LEN] = {0};
-	int ret, i;
-
-	ret = sscanf(str, "[%x:%x.%x]=%s", &bus, &dev, &fn, acpiid);
-	if (ret != 4) {
-		ret = sscanf(str, "[%x:%x:%x.%x]=%s", &seg, &bus, &dev, &fn, acpiid);
-		if (ret != 5) {
-			pr_err("Invalid command line: ivrs_acpihid(%s)\n", str);
-			return 1;
+	int i;
+
+	addr = strchr(str, '@');
+	if (!addr) {
+		if (sscanf(str, "[%x:%x.%x]=%s", &bus, &dev, &fn, acpiid) == 4 ||
+		    sscanf(str, "[%x:%x:%x.%x]=%s", &seg, &bus, &dev, &fn, acpiid) == 5) {
+			pr_warn("ivrs_acpihid%s option format deprecated; use ivrs_acpihid=%s@%04x:%02x:%02x.%d instead\n",
+				str, acpiid, seg, bus, dev, fn);
+			goto found;
 		}
+		goto not_found;
 	}
 
+	/* We have the '@', make it the terminator to get just the acpiid */
+	*addr++ = 0;
+
+	if (sscanf(str, "=%s", acpiid) != 1)
+		goto not_found;
+
+	if (sscanf(addr, "%x:%x.%x", &bus, &dev, &fn) == 3 ||
+	    sscanf(addr, "%x:%x:%x.%x", &seg, &bus, &dev, &fn) == 4)
+		goto found;
+
+not_found:
+	pr_err("Invalid command line: ivrs_acpihid%s\n", str);
+	return 1;
+
+found:
 	p = acpiid;
 	hid = strsep(&p, ":");
 	uid = p;