arm64: Cleanup VTCR_EL2 and VTTBR field values

We share most of the bits for VTCR_EL2 for different page sizes,
except for the TG0 value and the entry level value. This patch
makes the definitions a bit more cleaner to reflect this fact.

Also cleans up the VTTBR_X calculation. No functional changes.

Cc: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

arch/arm64/include/asm/kvm_arm.h

@@ -144,30 +144,32 @@
  * The magic numbers used for VTTBR_X in this patch can be found in Tables
  * D4-23 and D4-25 in ARM DDI 0487A.b.
  */
+
+#define VTCR_EL2_T0SZ_IPA	VTCR_EL2_T0SZ_40B
+#define VTCR_EL2_COMMON_BITS	(VTCR_EL2_SH0_INNER | VTCR_EL2_ORGN0_WBWA | \
+				 VTCR_EL2_IRGN0_WBWA | VTCR_EL2_RES1)
+
 #ifdef CONFIG_ARM64_64K_PAGES
 /*
  * Stage2 translation configuration:
- * 40bits input  (T0SZ = 24)
  * 64kB pages (TG0 = 1)
  * 2 level page tables (SL = 1)
  */
-#define VTCR_EL2_FLAGS		(VTCR_EL2_TG0_64K | VTCR_EL2_SH0_INNER | \
-				 VTCR_EL2_ORGN0_WBWA | VTCR_EL2_IRGN0_WBWA | \
-				 VTCR_EL2_SL0_LVL1 | VTCR_EL2_RES1)
-#define VTTBR_X		(38 - VTCR_EL2_T0SZ_40B)
+#define VTCR_EL2_TGRAN_FLAGS		(VTCR_EL2_TG0_64K | VTCR_EL2_SL0_LVL1)
+#define VTTBR_X_TGRAN_MAGIC		38
 #else
 /*
  * Stage2 translation configuration:
- * 40bits input  (T0SZ = 24)
  * 4kB pages (TG0 = 0)
  * 3 level page tables (SL = 1)
  */
-#define VTCR_EL2_FLAGS		(VTCR_EL2_TG0_4K | VTCR_EL2_SH0_INNER | \
-				 VTCR_EL2_ORGN0_WBWA | VTCR_EL2_IRGN0_WBWA | \
-				 VTCR_EL2_SL0_LVL1 | VTCR_EL2_RES1)
-#define VTTBR_X		(37 - VTCR_EL2_T0SZ_40B)
+#define VTCR_EL2_TGRAN_FLAGS		(VTCR_EL2_TG0_4K | VTCR_EL2_SL0_LVL1)
+#define VTTBR_X_TGRAN_MAGIC		37
 #endif
 
+#define VTCR_EL2_FLAGS			(VTCR_EL2_COMMON_BITS | VTCR_EL2_TGRAN_FLAGS)
+#define VTTBR_X				(VTTBR_X_TGRAN_MAGIC - VTCR_EL2_T0SZ_IPA)
+
 #define VTTBR_BADDR_SHIFT (VTTBR_X - 1)
 #define VTTBR_BADDR_MASK  (((UL(1) << (PHYS_MASK_SHIFT - VTTBR_X)) - 1) << VTTBR_BADDR_SHIFT)
 #define VTTBR_VMID_SHIFT  (UL(48))