[RFC PATCH 1/1] arm64: Add boot time configuration of Intermediate Physical Address size

[mohun106@gmail.com (mohun106 at gmail.com)]

From: Radha Mohan Chintakuntla <rchintakuntla@cavium.com>

ARMv8 supports a range of physical address bit sizes. The PARange bits
from ID_AA64MMFR0_EL1 register are read during boot-time and the
intermediate physical address size bits are written in the translation
control registers (TCR_EL1 and VTCR_EL2).

There is no change in the VA bits and levels of translation.

Signed-off-by: Radha Mohan Chintakuntla <rchintakuntla@cavium.com>
---
 arch/arm64/include/asm/kvm_arm.h       |   15 ++++++---------
 arch/arm64/include/asm/pgtable-hwdef.h |    5 ++---
 arch/arm64/kvm/hyp-init.S              |    7 +++++++
 arch/arm64/mm/proc.S                   |    9 ++++++++-
 4 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index 0eb3986..21ef48d 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -106,7 +106,6 @@
 
 /* VTCR_EL2 Registers bits */
 #define VTCR_EL2_PS_MASK	(7 << 16)
-#define VTCR_EL2_PS_40B		(2 << 16)
 #define VTCR_EL2_TG0_MASK	(1 << 14)
 #define VTCR_EL2_TG0_4K		(0 << 14)
 #define VTCR_EL2_TG0_64K	(1 << 14)
@@ -129,10 +128,9 @@
  * 64kB pages (TG0 = 1)
  * 2 level page tables (SL = 1)
  */
-#define VTCR_EL2_FLAGS		(VTCR_EL2_PS_40B | VTCR_EL2_TG0_64K | \
-				 VTCR_EL2_SH0_INNER | VTCR_EL2_ORGN0_WBWA | \
-				 VTCR_EL2_IRGN0_WBWA | VTCR_EL2_SL0_LVL1 | \
-				 VTCR_EL2_T0SZ_40B)
+#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_T0SZ_40B)
 #define VTTBR_X		(38 - VTCR_EL2_T0SZ_40B)
 #else
 /*
@@ -142,10 +140,9 @@
  * 4kB pages (TG0 = 0)
  * 3 level page tables (SL = 1)
  */
-#define VTCR_EL2_FLAGS		(VTCR_EL2_PS_40B | VTCR_EL2_TG0_4K | \
-				 VTCR_EL2_SH0_INNER | VTCR_EL2_ORGN0_WBWA | \
-				 VTCR_EL2_IRGN0_WBWA | VTCR_EL2_SL0_LVL1 | \
-				 VTCR_EL2_T0SZ_40B)
+#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_T0SZ_40B)
 #define VTTBR_X		(37 - VTCR_EL2_T0SZ_40B)
 #endif
 
diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h
index b1d2e26..f7af66b 100644
--- a/arch/arm64/include/asm/pgtable-hwdef.h
+++ b/arch/arm64/include/asm/pgtable-hwdef.h
@@ -100,9 +100,9 @@
 #define PTE_HYP			PTE_USER
 
 /*
- * 40-bit physical address supported.
+ * Highest possible physical address supported.
  */
-#define PHYS_MASK_SHIFT		(40)
+#define PHYS_MASK_SHIFT		(48)
 #define PHYS_MASK		((UL(1) << PHYS_MASK_SHIFT) - 1)
 
 /*
@@ -122,7 +122,6 @@
 #define TCR_SHARED		((UL(3) << 12) | (UL(3) << 28))
 #define TCR_TG0_64K		(UL(1) << 14)
 #define TCR_TG1_64K		(UL(1) << 30)
-#define TCR_IPS_40BIT		(UL(2) << 32)
 #define TCR_ASID16		(UL(1) << 36)
 #define TCR_TBI0		(UL(1) << 37)
 
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 2b0244d..642fec9 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -68,6 +68,13 @@ __do_hyp_init:
 	msr	tcr_el2, x4
 
 	ldr	x4, =VTCR_EL2_FLAGS
+	/*
+	 * Read the PARange bits from ID_AA64MMFR0_EL1 and set the PS bits in
+	 * VTCR_EL2.
+	 */
+	mrs	x5, ID_AA64MMFR0_EL1
+	ubfiz	x5, x5, #16, #3
+	orr	x4, x4, x5
 	msr	vtcr_el2, x4
 
 	mrs	x4, mair_el1
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 1333e6f..0657247 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -215,8 +215,15 @@ ENTRY(__cpu_setup)
 	 * Set/prepare TCR and TTBR. We use 512GB (39-bit) address range for
 	 * both user and kernel.
 	 */
-	ldr	x10, =TCR_TxSZ(VA_BITS) | TCR_FLAGS | TCR_IPS_40BIT | \
+	ldr	x10, =TCR_TxSZ(VA_BITS) | TCR_FLAGS | \
 		      TCR_ASID16 | TCR_TBI0 | (1 << 31)
+	/*
+	 * Read the PARange bits from ID_AA64MMFR0_EL1 and set the IPS bits in
+	 * TCR_EL1.
+	 */
+	mrs	x9, ID_AA64MMFR0_EL1
+	ubfiz	x9, x9, #32, #3
+	orr	x10, x10, x9
 #ifdef CONFIG_ARM64_64K_PAGES
 	orr	x10, x10, TCR_TG0_64K
 	orr	x10, x10, TCR_TG1_64K
-- 
1.7.1