Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
IronPort-SDR: htOd6o5yqzRlGh/7OmH5DbfJcx1ilL7MXmBCdEq8FNx8BzU5O/KGf09sOoktSAaQs8Z0CNNcKg
 OYXKqGSjGZ0Q==
IronPort-SDR: Y//QYvkquYurrVFuMqLqQs4CM2o1FKdB5yEJHDIq8L/suAzq4RbZg70TElHaOJIBHtqq0hhn3l
 Q/hQuzzc3E2Q==
From:   "Bae, Chang Seok" <chang.seok.bae@intel.com>
To:     Borislav Petkov <bp@suse.de>
CC:     Andy Lutomirski <luto@kernel.org>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "mingo@kernel.org" <mingo@kernel.org>,
        "x86@kernel.org" <x86@kernel.org>,
        "Brown, Len" <len.brown@intel.com>,
        "Hansen, Dave" <dave.hansen@intel.com>,
        "Liu, Jing2" <jing2.liu@intel.com>,
        "Shankar, Ravi V" <ravi.v.shankar@intel.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [PATCH v3 10/21] x86/fpu/xstate: Update xstate save function to
 support dynamic xstate
Thread-Topic: [PATCH v3 10/21] x86/fpu/xstate: Update xstate save function to
 support dynamic xstate
Thread-Index: AQHW2UTrfabGiuGaq0+dx4jPc8ZDRKpOes+AgAHIvAA=
Date:   Tue, 9 Feb 2021 15:48:42 +0000
Message-ID: <F16A56D8-803E-4B9C-BAA0-B16753BB273C@intel.com>
References: <20201223155717.19556-1-chang.seok.bae@intel.com>
 <20201223155717.19556-11-chang.seok.bae@intel.com>
 <20210208123359.GG17908@zn.tnic>
In-Reply-To: <20210208123359.GG17908@zn.tnic>
Accept-Language: en-US
Content-Language: en-US
Content-Type: text/plain; charset="us-ascii"
Content-ID: <4C30D23ACD28D94A9E7F9B97CFF05237@namprd11.prod.outlook.com>
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: ff0be20c-9bee-4ce3-2b2f-08d8cd122d84
X-MS-Exchange-CrossTenant-originalarrivaltime: 09 Feb 2021 15:48:42.7775
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: 94IfpqWlOUiK8h5Eh9KfYYmVHmpWQvCNfY7Qnd4oni9ZdZfWV4Z4Cg8hJa0NWaKo+1YvA+Wq01K8b9MV325gIuopcSW0lCP3jm9X8KyKGD8=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR11MB4853
X-OriginatorOrg: intel.com
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Feb 8, 2021, at 04:33, Borislav Petkov <bp@suse.de> wrote:
> On Wed, Dec 23, 2020 at 07:57:06AM -0800, Chang S. Bae wrote:
>> copy_xregs_to_kernel() used to save all user states in a kernel buffer.
>> When the dynamic user state is enabled, it becomes conditional which sta=
te
>> to be saved.
>>=20
>> fpu->state_mask can indicate which state components are reserved to be
>> saved in XSAVE buffer. Use it as XSAVE's instruction mask to select stat=
es.
>>=20
>> KVM used to save all xstate via copy_xregs_to_kernel(). Update KVM to se=
t a
>> valid fpu->state_mask, which will be necessary to correctly handle dynam=
ic
>> state buffers.
>=20
> All this commit message should say is something along the lines of
> "extend copy_xregs_to_kernel() to receive a mask argument of which
> states to save, in preparation of dynamic states handling."

Yes, I will change like that. Thanks.

>> No functional change until the kernel supports dynamic user states.
>=20
> Same comment as before.

This needs to be removed as per your comment [1].

Chang

[1] https://lore.kernel.org/lkml/20210209124906.GC15909@zn.tnic/=