[PATCH v3 5/5] KVM: arm64: Document HDBSS ioctl
From: Tian Zheng <hidden>
Date: 2026-02-25 04:04:28
Also in:
kvm, kvmarm, linux-doc, lkml
Subsystem:
documentation, kernel virtual machine (kvm), the rest · Maintainers:
Jonathan Corbet, Paolo Bonzini, Linus Torvalds
A new ioctl (KVM_CAP_ARM_HW_DIRTY_STATE_TRACK) provides a mechanism for userspace to configure the HDBSS buffer size during live migration, enabling hardware-assisted dirty page tracking. Signed-off-by: eillon <redacted> Signed-off-by: Tian Zheng <redacted> --- Documentation/virt/kvm/api.rst | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index fc5736839edd..2b5531d40d02 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst@@ -8896,6 +8896,22 @@ helpful if user space wants to emulate instructions which are not This capability can be enabled dynamically even if VCPUs were already created and are running. +7.47 KVM_CAP_ARM_HW_DIRTY_STATE_TRACK +---------------------------- + +:Architectures: arm64 +:Type: VM +:Parameters: args[0] is the allocation order determining HDBSS buffer size + args[1] is 0 to disable, 1 to enable HDBSS +:Returns: 0 on success, negative value on failure + +Enables hardware-assisted dirty page tracking via the Hardware Dirty State +Tracking Structure (HDBSS). + +When live migration is initiated, userspace can enable this feature by +setting KVM_CAP_ARM_HW_DIRTY_STATE_TRACK through IOCTL. KVM will allocate +per-vCPU HDBSS buffers. + 8. Other capabilities. ====================== --
2.33.0