[PATCH 05/12] 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.

Signed-off-by: Keqian Zhu <zhukeqian1@xxxxxxxxxx>
---
 arch/arm64/include/asm/kvm_host.h |  7 +++++++
 arch/arm64/kvm/arm.c              | 10 ++++++++++
 arch/arm64/kvm/reset.c            |  5 +++++
 include/uapi/linux/kvm.h          |  1 +
 tools/include/uapi/linux/kvm.h    |  1 +
 5 files changed, 24 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 9ea2dcfd609c..2bc3256759e3 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -95,6 +95,13 @@ struct kvm_arch {
 	 * supported.
 	 */
 	bool return_nisv_io_abort_to_user;
+
+	/*
+	 * Use hardware management of dirty status (DBM) to log dirty pages.
+	 * Userspace can enable this feature if KVM_CAP_ARM_HW_DIRTY_LOG is
+	 * supported.
+	 */
+	bool hw_dirty_log;
 };
 
 #define KVM_NR_MEM_OBJS     40
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 90cb90561446..850cc5cbc6f0 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -87,6 +87,16 @@ 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 ((cap->args[0] & ~1) || !kvm_hw_dbm_enabled()) {
+			r = -EINVAL;
+		} else {
+			r = 0;
+			kvm->arch.hw_dirty_log = cap->args[0];
+		}
+		break;
+#endif
 	default:
 		r = -EINVAL;
 		break;
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index d3b209023727..52bb801c9b2c 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 = kvm_hw_dbm_enabled();
+		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 fdd632c833b4..53908a8881a4 100644
--- a/tools/include/uapi/linux/kvm.h
+++ b/tools/include/uapi/linux/kvm.h
@@ -1017,6 +1017,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_S390_VCPU_RESETS 179
 #define KVM_CAP_S390_PROTECTED 180
 #define KVM_CAP_PPC_SECURE_GUEST 181
+#define KVM_CAP_ARM_HW_DIRTY_LOG 184
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
-- 
2.19.1