iommu/amd: Add sanity check for interrupt remapping table length macros

Currently, macros related to the interrupt remapping table length are
defined separately. This has resulted in an oversight in which one of
the macros were missed when changing the length. To prevent this,
redefine the macros to add built-in sanity check.

Also, rename macros to use the name of the DTE[IntTabLen] field as
specified in the AMD IOMMU specification. There is no functional change.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Will Deacon <will@kernel.org>
Cc: Jerry Snitselaar <jsnitsel@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Link: https://lore.kernel.org/r/20201210162436.126321-1-suravee.suthikulpanit@amd.com
Signed-off-by: Will Deacon <will@kernel.org>

drivers/iommu/amd/amd_iommu_types.h

@@ -255,11 +255,19 @@
 /* Bit value definition for dte irq remapping fields*/
 #define DTE_IRQ_PHYS_ADDR_MASK	(((1ULL << 45)-1) << 6)
 #define DTE_IRQ_REMAP_INTCTL_MASK	(0x3ULL << 60)
-#define DTE_IRQ_TABLE_LEN_MASK	(0xfULL << 1)
 #define DTE_IRQ_REMAP_INTCTL    (2ULL << 60)
-#define DTE_IRQ_TABLE_LEN       (9ULL << 1)
 #define DTE_IRQ_REMAP_ENABLE    1ULL
 
+/*
+ * AMD IOMMU hardware only support 512 IRTEs despite
+ * the architectural limitation of 2048 entries.
+ */
+#define DTE_INTTAB_ALIGNMENT    128
+#define DTE_INTTABLEN_VALUE     9ULL
+#define DTE_INTTABLEN           (DTE_INTTABLEN_VALUE << 1)
+#define DTE_INTTABLEN_MASK      (0xfULL << 1)
+#define MAX_IRQS_PER_TABLE      (1 << DTE_INTTABLEN_VALUE)
+
 #define PAGE_MODE_NONE    0x00
 #define PAGE_MODE_1_LEVEL 0x01
 #define PAGE_MODE_2_LEVEL 0x02
@@ -409,13 +417,6 @@ extern bool amd_iommu_np_cache;
 /* Only true if all IOMMUs support device IOTLBs */
 extern bool amd_iommu_iotlb_sup;
 
-/*
- * AMD IOMMU hardware only support 512 IRTEs despite
- * the architectural limitation of 2048 entries.
- */
-#define MAX_IRQS_PER_TABLE	512
-#define IRQ_TABLE_ALIGNMENT	128
-
 struct irq_remap_table {
 	raw_spinlock_t lock;
 	unsigned min_index;

drivers/iommu/amd/init.c

@@ -989,10 +989,10 @@ static bool copy_device_table(void)
 
 		irq_v = old_devtb[devid].data[2] & DTE_IRQ_REMAP_ENABLE;
 		int_ctl = old_devtb[devid].data[2] & DTE_IRQ_REMAP_INTCTL_MASK;
-		int_tab_len = old_devtb[devid].data[2] & DTE_IRQ_TABLE_LEN_MASK;
+		int_tab_len = old_devtb[devid].data[2] & DTE_INTTABLEN_MASK;
 		if (irq_v && (int_ctl || int_tab_len)) {
 			if ((int_ctl != DTE_IRQ_REMAP_INTCTL) ||
-			    (int_tab_len != DTE_IRQ_TABLE_LEN)) {
+			    (int_tab_len != DTE_INTTABLEN)) {
 				pr_err("Wrong old irq remapping flag: %#x\n", devid);
 				return false;
 			}
@@ -2674,7 +2674,7 @@ static int __init early_amd_iommu_init(void)
 			remap_cache_sz = MAX_IRQS_PER_TABLE * (sizeof(u64) * 2);
 		amd_iommu_irq_cache = kmem_cache_create("irq_remap_cache",
 							remap_cache_sz,
-							IRQ_TABLE_ALIGNMENT,
+							DTE_INTTAB_ALIGNMENT,
 							0, NULL);
 		if (!amd_iommu_irq_cache)
 			goto out;

drivers/iommu/amd/iommu.c

@@ -3191,7 +3191,7 @@ static void set_dte_irq_entry(u16 devid, struct irq_remap_table *table)
 	dte	&= ~DTE_IRQ_PHYS_ADDR_MASK;
 	dte	|= iommu_virt_to_phys(table->table);
 	dte	|= DTE_IRQ_REMAP_INTCTL;
-	dte	|= DTE_IRQ_TABLE_LEN;
+	dte	|= DTE_INTTABLEN;
 	dte	|= DTE_IRQ_REMAP_ENABLE;
 
 	amd_iommu_dev_table[devid].data[2] = dte;