kvm: arm64: Clean up VTCR_EL2 initialisation

Use the new helper for converting the parange to the physical shift.
Also, add the missing definitions for the VTCR_EL2 register fields
and use them instead of hard coding numbers.

Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <cdall@kernel.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

arch/arm64/include/asm/kvm_arm.h

@@ -107,6 +107,7 @@
 #define VTCR_EL2_RES1		(1 << 31)
 #define VTCR_EL2_HD		(1 << 22)
 #define VTCR_EL2_HA		(1 << 21)
+#define VTCR_EL2_PS_SHIFT	TCR_EL2_PS_SHIFT
 #define VTCR_EL2_PS_MASK	TCR_EL2_PS_MASK
 #define VTCR_EL2_TG0_MASK	TCR_TG0_MASK
 #define VTCR_EL2_TG0_4K		TCR_TG0_4K
@@ -127,6 +128,8 @@
 #define VTCR_EL2_VS_8BIT	(0 << VTCR_EL2_VS_SHIFT)
 #define VTCR_EL2_VS_16BIT	(1 << VTCR_EL2_VS_SHIFT)
 
+#define VTCR_EL2_T0SZ(x)	TCR_T0SZ(x)
+
 /*
  * We configure the Stage-2 page tables to always restrict the IPA space to be
  * 40 bits wide (T0SZ = 24).  Systems with a PARange smaller than 40 bits are

arch/arm64/kvm/hyp/s2-setup.c

@@ -19,45 +19,27 @@
 #include <asm/kvm_arm.h>
 #include <asm/kvm_asm.h>
 #include <asm/kvm_hyp.h>
+#include <asm/cpufeature.h>
 
 u32 __hyp_text __init_stage2_translation(void)
 {
 	u64 val = VTCR_EL2_FLAGS;
 	u64 parange;
+	u32 phys_shift;
 	u64 tmp;
 
 	/*
 	 * Read the PARange bits from ID_AA64MMFR0_EL1 and set the PS
-	 * bits in VTCR_EL2. Amusingly, the PARange is 4 bits, while
-	 * PS is only 3. Fortunately, bit 19 is RES0 in VTCR_EL2...
+	 * bits in VTCR_EL2. Amusingly, the PARange is 4 bits, but the
+	 * allocated values are limited to 3bits.
 	 */
 	parange = read_sysreg(id_aa64mmfr0_el1) & 7;
 	if (parange > ID_AA64MMFR0_PARANGE_MAX)
 		parange = ID_AA64MMFR0_PARANGE_MAX;
-	val |= parange << 16;
+	val |= parange << VTCR_EL2_PS_SHIFT;
 
 	/* Compute the actual PARange... */
-	switch (parange) {
-	case 0:
-		parange = 32;
-		break;
-	case 1:
-		parange = 36;
-		break;
-	case 2:
-		parange = 40;
-		break;
-	case 3:
-		parange = 42;
-		break;
-	case 4:
-		parange = 44;
-		break;
-	case 5:
-	default:
-		parange = 48;
-		break;
-	}
+	phys_shift = id_aa64mmfr0_parange_to_phys_shift(parange);
 
 	/*
 	 * ... and clamp it to 40 bits, unless we have some braindead
@@ -65,7 +47,7 @@ u32 __hyp_text __init_stage2_translation(void)
 	 * return that value for the rest of the kernel to decide what
 	 * to do.
 	 */
-	val |= 64 - (parange > 40 ? 40 : parange);
+	val |= VTCR_EL2_T0SZ(phys_shift > 40 ? 40 : phys_shift);
 
 	/*
 	 * Check the availability of Hardware Access Flag / Dirty Bit
@@ -86,5 +68,5 @@ u32 __hyp_text __init_stage2_translation(void)
 
 	write_sysreg(val, vtcr_el2);
 
-	return parange;
+	return phys_shift;
 }