From nobody Sat Apr 11 06:11:32 2026 Received: from canpmsgout08.his.huawei.com (canpmsgout08.his.huawei.com [113.46.200.223]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 54D96246788; Wed, 25 Feb 2026 04:04:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.223 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771992269; cv=none; b=KFnvbTkFDXGN5tmB8nRfqVgfdCtODulYA+UkGSrntt5HCq33p0dDDGh6L2Xc9DEi10AE/5RRsiXSY5qiMQJY8s9oEgIZ/+8J5ErqOi3LoUoKku+rD4eoiBmiiYTQt8hb/zLk2JsYf8GLiypELazF7AszT09pv5sLLd81xCTVMzA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771992269; c=relaxed/simple; bh=ufqMb//4EynTfTeBtA6ZVMpY+esPq4UpGRbeRU+KkQE=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=GIXRo0POIEt3rVK1d0WBHEbvbsJN0g1OQRu9Uj9l/bfyvo0fZsS5qy9oQEjcjiaFuJ7/s+poszvwMp2qXHiN7DYAQCNiSdglciAfemqNlWJj8hbC+sjrz+euE8JcHfZUjnAYPgbGn9+/BF3wzrcruuvSeZNDyqtRmd/kB0hJYsg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b=zDuE/x4D; arc=none smtp.client-ip=113.46.200.223 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b="zDuE/x4D" dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=jS9KMSv+2m6fUiDF1tdjjHI4QTWcbBOKczvR19neBjk=; b=zDuE/x4D/8nwKSb3wILbY6/6Y42DWJ5ub8M3+5beICBah5xaqHer4BfmYbmfvG10LcJCId9pU sCA5e7zzRQKD4Z+bNxR9rL5bPhr4dNGSHfp5KoVsN4EGrIU8ODCfbIbba7mQaf89YkfjpG1EQ6Q ZpHiMvdgLtJA5bTs1N9ixKw= Received: from mail.maildlp.com (unknown [172.19.162.92]) by canpmsgout08.his.huawei.com (SkyGuard) with ESMTPS id 4fLLSq15KRzmV6k; Wed, 25 Feb 2026 11:59:39 +0800 (CST) Received: from kwepemr100010.china.huawei.com (unknown [7.202.195.125]) by mail.maildlp.com (Postfix) with ESMTPS id C4A8340565; Wed, 25 Feb 2026 12:04:26 +0800 (CST) Received: from huawei.com (10.50.163.32) by kwepemr100010.china.huawei.com (7.202.195.125) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Wed, 25 Feb 2026 12:04:25 +0800 From: Tian Zheng To: , , , , , , CC: , , , , , , , , , , , , , , Subject: [PATCH v3 5/5] KVM: arm64: Document HDBSS ioctl Date: Wed, 25 Feb 2026 12:04:21 +0800 Message-ID: <20260225040421.2683931-6-zhengtian10@huawei.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20260225040421.2683931-1-zhengtian10@huawei.com> References: <20260225040421.2683931-1-zhengtian10@huawei.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: kwepems500002.china.huawei.com (7.221.188.17) To kwepemr100010.china.huawei.com (7.202.195.125) Content-Type: text/plain; charset="utf-8" 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 Signed-off-by: Tian Zheng --- 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. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D -- 2.33.0