iommu/amd: Add ioapic and hpet ivrs override

Add two new kernel commandline parameters ivrs_ioapic and
ivrs_hpet to override the Id->DeviceId mapping from the IVRS
ACPI table. This can be used to work around broken BIOSes to
get interrupt remapping working on AMD systems.
Tested-by: NBorislav Petkov <bp@suse.de>
Tested-by: NSuravee Suthikulanit <suravee.suthikulpanit@amd.com>
Reviewed-by: NShuah Khan <shuahkhan@gmail.com>
Signed-off-by: NJoerg Roedel <joro@8bytes.org>

drivers/iommu/amd_iommu_init.c

@@ -2145,8 +2145,68 @@ static int __init parse_amd_iommu_options(char *str)
 	return 1;
 }
 
-__setup("amd_iommu_dump", parse_amd_iommu_dump);
-__setup("amd_iommu=", parse_amd_iommu_options);
+static int __init parse_ivrs_ioapic(char *str)
+{
+	unsigned int bus, dev, fn;
+	int ret, id, i;
+	u16 devid;
+
+	ret = sscanf(str, "[%d]=%x:%x.%x", &id, &bus, &dev, &fn);
+
+	if (ret != 4) {
+		pr_err("AMD-Vi: Invalid command line: ivrs_ioapic%s\n", str);
+		return 1;
+	}
+
+	if (early_ioapic_map_size == EARLY_MAP_SIZE) {
+		pr_err("AMD-Vi: Early IOAPIC map overflow - ignoring ivrs_ioapic%s\n",
+			str);
+		return 1;
+	}
+
+	devid = ((bus & 0xff) << 8) | ((dev & 0x1f) << 3) | (fn & 0x7);
+
+	i				= early_ioapic_map_size++;
+	early_ioapic_map[i].id		= id;
+	early_ioapic_map[i].devid	= devid;
+	early_ioapic_map[i].cmd_line	= true;
+
+	return 1;
+}
+
+static int __init parse_ivrs_hpet(char *str)
+{
+	unsigned int bus, dev, fn;
+	int ret, id, i;
+	u16 devid;
+
+	ret = sscanf(str, "[%d]=%x:%x.%x", &id, &bus, &dev, &fn);
+
+	if (ret != 4) {
+		pr_err("AMD-Vi: Invalid command line: ivrs_hpet%s\n", str);
+		return 1;
+	}
+
+	if (early_hpet_map_size == EARLY_MAP_SIZE) {
+		pr_err("AMD-Vi: Early HPET map overflow - ignoring ivrs_hpet%s\n",
+			str);
+		return 1;
+	}
+
+	devid = ((bus & 0xff) << 8) | ((dev & 0x1f) << 3) | (fn & 0x7);
+
+	i				= early_hpet_map_size++;
+	early_hpet_map[i].id		= id;
+	early_hpet_map[i].devid		= devid;
+	early_hpet_map[i].cmd_line	= true;
+
+	return 1;
+}
+
+__setup("amd_iommu_dump",	parse_amd_iommu_dump);
+__setup("amd_iommu=",		parse_amd_iommu_options);
+__setup("ivrs_ioapic",		parse_ivrs_ioapic);
+__setup("ivrs_hpet",		parse_ivrs_hpet);
 
 IOMMU_INIT_FINISH(amd_iommu_detect,
 		  gart_iommu_hole_init,