Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 18 Oct 2022 13:07:29 -0700
From:   Ashok Raj <ashok.raj@intel.com>
To:     "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
CC:     Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>, <x86@kernel.org>,
        Kostya Serebryany <kcc@google.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Alexander Potapenko <glider@google.com>,
        Taras Madan <tarasmadan@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        "H . J . Lu" <hjl.tools@gmail.com>,
        Andi Kleen <ak@linux.intel.com>,
        Rick Edgecombe <rick.p.edgecombe@intel.com>,
        "Bharata B Rao" <bharata@amd.com>,
        Jacob Pan <jacob.jun.pan@linux.intel.com>,
        <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
        Ashok Raj <ashok.raj@intel.com>
Subject: Re: [PATCHv10 10/15] x86/mm, iommu/sva: Make LAM and SVM mutually
 exclusive
Message-ID: <Y08HgXqvNSpTUgWe@a4bf019067fa.jf.intel.com>
References: <20221018113358.7833-1-kirill.shutemov@linux.intel.com>
 <20221018113358.7833-11-kirill.shutemov@linux.intel.com>
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <20221018113358.7833-11-kirill.shutemov@linux.intel.com>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?mQXM8qKqkweVlYtHceOu+hkM77sZ4zr860SAiclfJzEN1LHPEKXoFHHfTvJB?=
 =?us-ascii?Q?XzHZFn5mlWeIL82qIm9cVG1eotpIhUo+owm6BS5IVxU4KSBChZ3171eIHmZt?=
 =?us-ascii?Q?/F8d0xhmjTDWlcAed0Mq/Jtwkwmf0EegAmh1WTvMjYpFhV9fo324zz/Nw4DL?=
 =?us-ascii?Q?4kCAyNH+XZmaoKuiYeSrg516JodcRx6hXrSCboNRfml3yEhcSGbsR046OBjw?=
 =?us-ascii?Q?oFJ8l3Lm+mlDilXYwj92PUDx0OxmXEy8IbAhg9BYSgFZxwJecOQS+fUinfrq?=
 =?us-ascii?Q?N1JSF3qCs2s/Aor8gonzxnqcDjQUuYuzYSBfkrWLwpIdDF4Qbxg5TLZjl2uv?=
 =?us-ascii?Q?TY2S4rWENFCnKyOTTdh3ZPxkJjHN3LGNym67d8rCejxTk0JFwSgHOxuMy8Dm?=
 =?us-ascii?Q?8UOFQuTxgoOAgM+o8xwCQSeNedTCZmWnTXbMWLe81Rl/fJW/DA8FOtx6+2qO?=
 =?us-ascii?Q?+rXwcnSflwlhPQQavphRK7vEeuO3ejTOQEZfcW38tHPyXburiXERgaLtFs/p?=
 =?us-ascii?Q?phN7y6REjQ2aNzIHOYOb3RlAbwaLlH9EvmWZjEShJH/0YZyDsmeAlz+IZiZn?=
 =?us-ascii?Q?FX1SciERhf372YQNs3+2/IBop8ZBXv9UaFdaMbdVTT73uRS+0NxNoo9L/Aea?=
 =?us-ascii?Q?sciyjmX9jkhJ3R4BMUNBUhBxiTQI6r/aFmGBLiZ1DW64SLezqoYYisLy5OqG?=
 =?us-ascii?Q?/RGTkqElBqE1wnVmU6mPd057uLS/fY1Uq7ZB+9eawrp0DJiERj/qkamZHtwc?=
 =?us-ascii?Q?ti7oZ/OsYh3XbkmRImBN0VSPlmcLN85DaDlK0Lcbh8XeujrKWhC0DjJ5fprD?=
 =?us-ascii?Q?Ex06ov1r84hMXu7p0jDbc98qWVsufuaT4ju4+G4XPauT75h+u9HV3tCFdXEc?=
 =?us-ascii?Q?AdySJrk5yxH8+eTnJuEN8UIrYRUT4ZC22dU0/NkTkzBGvTYe9N7U3px7D/F5?=
 =?us-ascii?Q?XDIlXew4w7jORqAVY1AvyMCHv1c6RtKieFe7SD+OG4bJLli0AxjXNNef+8z9?=
 =?us-ascii?Q?2ZuEqBiyqyAiBkGu7UbzoQFsFkjAwglSFiorQMX3I/XAtaeo4nbtg7PzO+iM?=
 =?us-ascii?Q?DkXJ9FDvFhK5aBgFEX4J9vveVlzuOOcaWqFZK3r0MWCo4ZFGvpqgovYob/0G?=
 =?us-ascii?Q?QwoFtDzPvvHca3PP9VszjVzGdD6fynZtFFfTQ+3SJZaGA5m3JK3J8OHVDJq8?=
 =?us-ascii?Q?pFJwkSU3GBXfaBdOSCfIknYPyiaHFVNsvzIvzJzhxOomd5ZI/Deiv4jXKn67?=
 =?us-ascii?Q?Z4RAyNIvHuLQw0RU6EvaAjYMwFpcoYW2Chqegf+dvZqJsw0bvEl4NEtdlcUv?=
 =?us-ascii?Q?oqd0W2Z3gRaCoowiOFbXucJTgmfc326UIhRfbAFr4Is9IbPg69oBVWaDj+dB?=
 =?us-ascii?Q?pSNRbuRZbs9+8Ff+2PIsXpYr7ta+ayx7SBWaOVJsF34gkU8rx4fERsLJja7A?=
 =?us-ascii?Q?4jpgTexfYyPBzEwkiVDa+/8+VQqlhu8jo6u/sfZUyk3fUWnRE0BabfQXVqxA?=
 =?us-ascii?Q?sKy9wcGsZZi8hFFthFkNGLFwrnniTN4n3isn90ShfK2WD3P9JM4Ideb9MKhq?=
 =?us-ascii?Q?P22jhBsMsMR+IIxD9V16cD8c/lULnuVyuoMvkDLkThSwtAF0ms/u9+weveTn?=
 =?us-ascii?Q?mw=3D=3D?=
X-MS-Exchange-CrossTenant-Network-Message-Id: ed8c9c36-0df1-4e79-d7dd-08dab14476d2
X-MS-Exchange-CrossTenant-AuthSource: SJ1PR11MB6201.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Oct 2022 20:08:03.7174
 (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: 9asnlw1h6w7Fmuh8u0dtkjMLBaxHF98U4dPPDyKcZDTrZSe9eVkbt1ZXDY5dTdh6UM9/jEyN9SRnYbeXIE0wUA==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR11MB5610
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=-4.7 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,
        RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE
        autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Tue, Oct 18, 2022 at 02:33:53PM +0300, Kirill A. Shutemov wrote:
> IOMMU and SVM-capable devices know nothing about LAM and only expect
> canonical addresses. Attempt to pass down tagged pointer will lead to
> address translation failure.
> 
> By default do not allow to enable both LAM and use SVM in the same
> process.
> 
> The new ARCH_FORCE_TAGGED_SVM arch_prctl() overrides the limitation.
> By using the arch_prctl() userspace takes responsibility to never pass
> tagged address to the device.

Reviewed-by: Ashok Raj <ashok.raj@intel.com>

> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
>  arch/x86/include/asm/mmu.h         |  6 ++++--
>  arch/x86/include/asm/mmu_context.h |  2 ++
>  arch/x86/include/uapi/asm/prctl.h  |  1 +
>  arch/x86/kernel/process_64.c       | 13 +++++++++++++
>  drivers/iommu/iommu-sva-lib.c      | 12 ++++++++++++
>  include/linux/mmu_context.h        |  4 ++++
>  6 files changed, 36 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h
> index 2fdb390040b5..cce9b32b0d6d 100644
> --- a/arch/x86/include/asm/mmu.h
> +++ b/arch/x86/include/asm/mmu.h
> @@ -9,9 +9,11 @@
>  #include <linux/bits.h>
>  
>  /* Uprobes on this MM assume 32-bit code */
> -#define MM_CONTEXT_UPROBE_IA32	BIT(0)
> +#define MM_CONTEXT_UPROBE_IA32		BIT(0)
>  /* vsyscall page is accessible on this MM */
> -#define MM_CONTEXT_HAS_VSYSCALL	BIT(1)
> +#define MM_CONTEXT_HAS_VSYSCALL		BIT(1)

Nit: Looks like the two above format changes got in here :-)

Cheers,
Ashok