linux-kernel - [PATCH v2 5/5] KVM: arm64: Document HDBSS ioctl

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20251121092342.3393318-6-zhengtian10@huawei.com>
Date: Fri, 21 Nov 2025 17:23:42 +0800
From: Tian Zheng <zhengtian10@...wei.com>
To: <maz@...nel.org>, <oliver.upton@...ux.dev>, <catalin.marinas@....com>,
	<corbet@....net>, <pbonzini@...hat.com>, <will@...nel.org>
CC: <linux-kernel@...r.kernel.org>, <zhengtian10@...wei.com>,
	<yuzenghui@...wei.com>, <wangzhou1@...ilicon.com>, <yezhenyu2@...wei.com>,
	<xiexiangyou@...wei.com>, <zhengchuan@...wei.com>, <linuxarm@...wei.com>,
	<joey.gouly@....com>, <kvmarm@...ts.linux.dev>, <kvm@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-doc@...r.kernel.org>,
	<suzuki.poulose@....com>
Subject: [PATCH v2 5/5] KVM: arm64: Document HDBSS ioctl

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 <yezhenyu2@...wei.com>
Signed-off-by: Tian Zheng <zhengtian10@...wei.com>
---
 Documentation/virt/kvm/api.rst | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 57061fa29e6a..25d60ff136e9 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -8703,6 +8703,21 @@ This capability indicate to the userspace whether a PFNMAP memory region
 can be safely mapped as cacheable. This relies on the presence of
 force write back (FWB) feature support on the hardware.

+7.44 KVM_CAP_ARM_HW_DIRTY_STATE_TRACK
+:Architectures: arm64
+:Type: VM
+:Parameters: args[0] is the allocation order determining HDBSS buffer size
+: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.
+
+The feature is disabled by invoking the ioctl again.
+
 8. Other capabilities.
 ======================

--
2.33.0