[PATCH v2 6/8] KVM: arm64: Add KVM_CAP_ARM_HW_DIRTY_LOG capability

[Keqian Zhu]

For that using arm64 DBM to log dirty pages has the side effect
of long time dirty log sync, we should give userspace opportunity
to enable or disable this feature, to realize some policy.

This feature is disabled by default.

Signed-off-by: Keqian Zhu <zhukeqian1 at huawei.com>
Signed-off-by: Peng Liang <liangpeng10 at huawei.com>
---
 arch/arm64/include/asm/kvm_host.h |  1 +
 arch/arm64/kvm/arm.c              | 35 +++++++++++++++++++++++++++++++
 arch/arm64/kvm/mmu.c              | 22 +++++++++++++++++++
 arch/arm64/kvm/reset.c            |  5 +++++
 include/uapi/linux/kvm.h          |  1 +
 tools/include/uapi/linux/kvm.h    |  1 +
 6 files changed, 65 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 86b9c210ba43..69a5317c7049 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -481,6 +481,7 @@ u64 __kvm_call_hyp(void *hypfn, ...);
 void force_vm_exit(const cpumask_t *mask);
 void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot);
 void kvm_mmu_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot);
+void kvm_mmu_sync_dirty_log_all(struct kvm *kvm);
 
 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 		int exception_index);
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index fefa5406e037..9e3f765d5467 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -78,6 +78,11 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
 			    struct kvm_enable_cap *cap)
 {
 	int r;
+#ifdef CONFIG_ARM64_HW_AFDBM
+	int i;
+	struct kvm_vcpu *vcpu;
+	bool enable_hw_dirty_log;
+#endif
 
 	if (cap->flags)
 		return -EINVAL;
@@ -87,6 +92,36 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
 		r = 0;
 		kvm->arch.return_nisv_io_abort_to_user = true;
 		break;
+#ifdef CONFIG_ARM64_HW_AFDBM
+	case KVM_CAP_ARM_HW_DIRTY_LOG:
+		if (!arm_mmu_hw_dbm_supported() || (cap->args[0] & ~0x1))
+			r = -EINVAL;
+
+		enable_hw_dirty_log = !!(cap->args[0] & 0x1);
+		if (!!(kvm->arch.vtcr & VTCR_EL2_HD) != enable_hw_dirty_log) {
+			if (enable_hw_dirty_log)
+				kvm->arch.vtcr |= VTCR_EL2_HD;
+			else
+				kvm->arch.vtcr &= ~VTCR_EL2_HD;
+
+			/*
+			 * We should kick vcpus out of guest mode here to
+			 * load new vtcr value to vtcr_el2 register when
+			 * re-enter guest mode.
+			 */
+			kvm_for_each_vcpu(i, vcpu, kvm)
+				kvm_vcpu_kick(vcpu);
+
+			if (!enable_hw_dirty_log) {
+				mutex_lock(&kvm->slots_lock);
+				kvm_mmu_sync_dirty_log_all(kvm);
+				mutex_unlock(&kvm->slots_lock);
+			}
+		}
+
+		r = 0;
+		break;
+#endif
 	default:
 		r = -EINVAL;
 		break;
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index adfa62f1fced..1a48554accb0 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -2590,6 +2590,28 @@ void kvm_mmu_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
 	spin_unlock(&kvm->mmu_lock);
 	srcu_read_unlock(&kvm->srcu, srcu_idx);
 }
+
+/**
+ * kvm_mmu_sync_dirty_log_all() - synchronize dirty log from PTEs for whole VM
+ * @kvm:	The KVM pointer
+ *
+ * Called with kvm->slots_lock mutex acquired
+ */
+void kvm_mmu_sync_dirty_log_all(struct kvm *kvm)
+{
+	struct kvm_memslots *slots = kvm_memslots(kvm);
+	struct kvm_memory_slot *memslots = slots->memslots;
+	struct kvm_memory_slot *memslot;
+	int slot;
+
+	if (unlikely(!slots->used_slots))
+		return;
+
+	for (slot = 0; slot < slots->used_slots; slot++) {
+		memslot = &memslots[slot];
+		kvm_mmu_sync_dirty_log(kvm, memslot);
+	}
+}
 #endif /* CONFIG_ARM64_HW_AFDBM */
 
 void kvm_arch_commit_memory_region(struct kvm *kvm,
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index d3b209023727..a3be703dd54b 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -83,6 +83,11 @@ int kvm_arch_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		r = has_vhe() && system_supports_address_auth() &&
 				 system_supports_generic_auth();
 		break;
+#ifdef CONFIG_ARM64_HW_AFDBM
+	case KVM_CAP_ARM_HW_DIRTY_LOG:
+		r = arm_mmu_hw_dbm_supported();
+		break;
+#endif /* CONFIG_ARM64_HW_AFDBM */
 	default:
 		r = 0;
 	}
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 4fdf30316582..e0b12c43397b 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1031,6 +1031,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_PPC_SECURE_GUEST 181
 #define KVM_CAP_HALT_POLL 182
 #define KVM_CAP_ASYNC_PF_INT 183
+#define KVM_CAP_ARM_HW_DIRTY_LOG 184
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
diff --git a/tools/include/uapi/linux/kvm.h b/tools/include/uapi/linux/kvm.h
index 4fdf30316582..e0b12c43397b 100644
--- a/tools/include/uapi/linux/kvm.h
+++ b/tools/include/uapi/linux/kvm.h
@@ -1031,6 +1031,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_PPC_SECURE_GUEST 181
 #define KVM_CAP_HALT_POLL 182
 #define KVM_CAP_ASYNC_PF_INT 183
+#define KVM_CAP_ARM_HW_DIRTY_LOG 184
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
-- 
2.19.1