[RFC PATCH 21/27] KVM: arm64: Refactor kvm_arm_setup_stage2()

[Quentin Perret]

In order to re-use some of the stage 2 setup at EL2, factor parts of
kvm_arm_setup_stage2() out into static inline functions.

No functional change intended.

Signed-off-by: Quentin Perret <qperret@xxxxxxxxxx>
---
 arch/arm64/include/asm/kvm_mmu.h | 48 ++++++++++++++++++++++++++++++++
 arch/arm64/kvm/reset.c           | 42 +++-------------------------
 2 files changed, 52 insertions(+), 38 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 714357ebd278..5a76358e8c7a 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -256,6 +256,54 @@ static inline int kvm_write_guest_lock(struct kvm *kvm, gpa_t gpa,
 	return ret;
 }
 
+static inline u64 kvm_get_parange(u64 mmfr0)
+{
+	u64 parange = cpuid_feature_extract_unsigned_field(mmfr0,
+				ID_AA64MMFR0_PARANGE_SHIFT);
+	if (parange > ID_AA64MMFR0_PARANGE_MAX)
+		parange = ID_AA64MMFR0_PARANGE_MAX;
+
+	return parange;
+}
+
+/*
+ * The VTCR value is common across all the physical CPUs on the system.
+ * We use system wide sanitised values to fill in different fields,
+ * except for Hardware Management of Access Flags. HA Flag is set
+ * unconditionally on all CPUs, as it is safe to run with or without
+ * the feature and the bit is RES0 on CPUs that don't support it.
+ */
+static inline u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift)
+{
+	u64 vtcr = VTCR_EL2_FLAGS;
+	u8 lvls;
+
+	vtcr |= kvm_get_parange(mmfr0) << VTCR_EL2_PS_SHIFT;
+	vtcr |= VTCR_EL2_T0SZ(phys_shift);
+	/*
+	 * Use a minimum 2 level page table to prevent splitting
+	 * host PMD huge pages at stage2.
+	 */
+	lvls = stage2_pgtable_levels(phys_shift);
+	if (lvls < 2)
+		lvls = 2;
+	vtcr |= VTCR_EL2_LVLS_TO_SL0(lvls);
+
+	/*
+	 * Enable the Hardware Access Flag management, unconditionally
+	 * on all CPUs. The features is RES0 on CPUs without the support
+	 * and must be ignored by the CPUs.
+	 */
+	vtcr |= VTCR_EL2_HA;
+
+	/* Set the vmid bits */
+	vtcr |= (get_vmid_bits(mmfr1) == 16) ?
+		VTCR_EL2_VS_16BIT :
+		VTCR_EL2_VS_8BIT;
+
+	return vtcr;
+}
+
 #define kvm_phys_to_vttbr(addr)		phys_to_ttbr(addr)
 
 static __always_inline u64 kvm_get_vttbr(struct kvm_s2_mmu *mmu)
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 3e772ea4e066..074b39dbe539 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -384,19 +384,10 @@ int kvm_set_ipa_limit(void)
 	return 0;
 }
 
-/*
- * Configure the VTCR_EL2 for this VM. The VTCR value is common
- * across all the physical CPUs on the system. We use system wide
- * sanitised values to fill in different fields, except for Hardware
- * Management of Access Flags. HA Flag is set unconditionally on
- * all CPUs, as it is safe to run with or without the feature and
- * the bit is RES0 on CPUs that don't support it.
- */
 int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long type)
 {
-	u64 vtcr = VTCR_EL2_FLAGS, mmfr0;
-	u32 parange, phys_shift;
-	u8 lvls;
+	u64 mmfr0, mmfr1;
+	u32 phys_shift;
 
 	if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
 		return -EINVAL;
@@ -411,33 +402,8 @@ int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long type)
 	}
 
 	mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
-	parange = cpuid_feature_extract_unsigned_field(mmfr0,
-				ID_AA64MMFR0_PARANGE_SHIFT);
-	if (parange > ID_AA64MMFR0_PARANGE_MAX)
-		parange = ID_AA64MMFR0_PARANGE_MAX;
-	vtcr |= parange << VTCR_EL2_PS_SHIFT;
-
-	vtcr |= VTCR_EL2_T0SZ(phys_shift);
-	/*
-	 * Use a minimum 2 level page table to prevent splitting
-	 * host PMD huge pages at stage2.
-	 */
-	lvls = stage2_pgtable_levels(phys_shift);
-	if (lvls < 2)
-		lvls = 2;
-	vtcr |= VTCR_EL2_LVLS_TO_SL0(lvls);
-
-	/*
-	 * Enable the Hardware Access Flag management, unconditionally
-	 * on all CPUs. The features is RES0 on CPUs without the support
-	 * and must be ignored by the CPUs.
-	 */
-	vtcr |= VTCR_EL2_HA;
+	mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
+	kvm->arch.vtcr = kvm_get_vtcr(mmfr0, mmfr1, phys_shift);
 
-	/* Set the vmid bits */
-	vtcr |= (kvm_get_vmid_bits() == 16) ?
-		VTCR_EL2_VS_16BIT :
-		VTCR_EL2_VS_8BIT;
-	kvm->arch.vtcr = vtcr;
 	return 0;
 }
-- 
2.29.2.299.gdc1121823c-goog