[RFC PATCH 7/7] KVM: arm64: Enable stage2 hardware DBM

[Keqian Zhu]

We are ready to support hw management of dirty state, enable it if
hardware support it.

Signed-off-by: Keqian Zhu <zhukeqian1@xxxxxxxxxx>
Signed-off-by: Peng Liang <liangpeng10@xxxxxxxxxx>
---
 arch/arm64/include/asm/sysreg.h | 2 ++
 arch/arm64/kvm/reset.c          | 9 ++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index ebc622432831..371ea6d65c16 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -721,6 +721,8 @@
 #define ID_AA64MMFR1_VMIDBITS_8		0
 #define ID_AA64MMFR1_VMIDBITS_16	2
 
+#define ID_AA64MMFR1_HADBS_DBS		2
+
 /* id_aa64mmfr2 */
 #define ID_AA64MMFR2_E0PD_SHIFT		60
 #define ID_AA64MMFR2_FWB_SHIFT		40
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 30b7ea680f66..cb727e1fb581 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -392,7 +392,7 @@ int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long type)
 {
 	u64 vtcr = VTCR_EL2_FLAGS;
 	u32 parange, phys_shift;
-	u8 lvls;
+	u8 lvls, hadbs;
 
 	if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
 		return -EINVAL;
@@ -428,6 +428,13 @@ int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long type)
 	 */
 	vtcr |= VTCR_EL2_HA;
 
+	hadbs = (read_sysreg(id_aa64mmfr1_el1) >>
+			ID_AA64MMFR1_HADBS_SHIFT) & 0xf;
+#ifdef CONFIG_ARM64_HW_AFDBM
+	if (hadbs == ID_AA64MMFR1_HADBS_DBS)
+		vtcr |= VTCR_EL2_HD;
+#endif
+
 	/* Set the vmid bits */
 	vtcr |= (kvm_get_vmid_bits() == 16) ?
 		VTCR_EL2_VS_16BIT :
-- 
2.19.1