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;
Subject: [PATCH 1/6] xen/x86: streamline set_pte_mfn()
From:   Jan Beulich <jbeulich@suse.com>
To:     Juergen Gross <jgross@suse.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc:     Stefano Stabellini <sstabellini@kernel.org>,
        lkml <linux-kernel@vger.kernel.org>,
        "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
References: <022b1a5e-4121-6bae-f07c-4ad5eac12481@suse.com>
Message-ID: <b39c08e8-4a53-8bca-e6e7-3684a6cab8d0@suse.com>
Date:   Thu, 30 Sep 2021 14:34:56 +0200
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101
 Thunderbird/78.14.0
In-Reply-To: <022b1a5e-4121-6bae-f07c-4ad5eac12481@suse.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?UFgzaXhGQkkrZHhQa2FhN1pXc0p6Yk8yRVBhNU1MaDRyVUJUUEsyWnZIdmxF?=
 =?utf-8?B?UkxYVnNwKythcGpMRld5b205U2hjd1JHc3JPZ25rdHhMZlJyT1dEOVl6ZzBr?=
 =?utf-8?B?MGVaNFprbDMxdFhBZmFkdzdrTjg1OXVjNHBaRjhUVklCTWRaejRDUll0UUlY?=
 =?utf-8?B?a3pqa2xraDE2TFBoUnhWRUpSdnVXcUNta1dKTzRkRllqN0t5TnZGanQ3Mlk5?=
 =?utf-8?B?Z1liTmp3NDhaRnRqNGlqZ0JEOElXRHVyelhISi9VLzBqY2VPUG9KRFJPK2ta?=
 =?utf-8?B?YU9KNnF1RFVKSXFGYlpSOTh3cVd5c3V2VWFoTFRGSHM0WUdiNWN5Ykw1Y21r?=
 =?utf-8?B?b3VKTTZtQUFMUzV4MmxuYlhZYjMxL3BqUDFpQ1ZmczB5M21wQ3Z4S1FyUzRR?=
 =?utf-8?B?K1BFV3hjL2Q3TVV5WUg5S1luQW9DQ2RDa3pOZnd6eWtzeEpaOXU4OWxXKzM4?=
 =?utf-8?B?U09peHgzM3FIZTVjejFsaFV3a0lOOFM2NUowcFdjZHpNMmhHaDlYaWNSWGpx?=
 =?utf-8?B?a1owemxEdnQ3Q01ML2VHRXMzUDBKRUFEUEpLY0cxWmdwKzJUMVg4cnRrUU9C?=
 =?utf-8?B?M24ycjQ4LytZQkR5MWV2b3lENjY2VGVSd0dzcnN5clZQYVJjYzZxVXRYMlg2?=
 =?utf-8?B?T1kwRmVreDB6TkNqRGhEMUtNQ1VaYTNlNE5TcGtOVGVRMmx3c2RiYXM0K25N?=
 =?utf-8?B?aEVzeTRRbWZVbFBLZHM0RVZSWlgxZTAyaUNRdEtqS0s4OWZ0Tm1HaWpRWUxl?=
 =?utf-8?B?ZHhoWFFzYjV3aUcxNklEa3VLaXNGUkhiM3c3c3R4ZmVaaWZwMWw0WkZVLy9W?=
 =?utf-8?B?M1haUmZJYnZMTHJleVhhd1ZmNFNYYlNLcXdCVVV0QUFBZXpjbnpZcWRvMHhL?=
 =?utf-8?B?WitxVlZrM2MrZjlWTXl2MXF6c21wZnlnVE0yMmUyd3FJOWhKc2JqSjNiNXU0?=
 =?utf-8?B?ZUs0STN5YWtlamxuSUhGcit4T0U5QjN1TnhGU1dmWTRoeTV3cDZ4QlpveGtm?=
 =?utf-8?B?MEdvNlI4MnprTlcxR0JONkZMQ2NhUEhTaElIaExoVUpZVTlEL0Jyb0JOY2lH?=
 =?utf-8?B?RUJPMXl3VlpqRmJzSkpBWVh0aklNU29DUkR6UTlMaTZTZ0ltNFlVTmlyWi9y?=
 =?utf-8?B?SXA0bldKdHIwTm8rYUlZUFo5bjR2RHVBU1FVbU1KY0RNYjlyRmQwSEdYWk93?=
 =?utf-8?B?ZnF3ekVkWk1UenU4Yk1heFQzUUpZbDZQbVBLaVd6ZHViNStwWkN1K1BOWkFI?=
 =?utf-8?B?aFJ6Ri9FV0dxZEh0ejNCRFRTWklnUytQS2tpc0phYjVnWEV2SGpMMmo1TGI5?=
 =?utf-8?B?NWVuamd4ZmJLNEl3cXRmdzRrMTFlaTVvQVUxczlqWE5CTlNGUDgvNzhXRTh5?=
 =?utf-8?B?UzZ3eEhwelQ3Q3RzOUdMeno0Z00vV2c4YzN5KzlDOXlBVnFrSkVtd2hPUi9a?=
 =?utf-8?B?QlZlczBodkVocVN6NldXWE01MkhwdUZFTC81SUY0RjkrOURKUzlMNWRKTUVB?=
 =?utf-8?B?ZVRsQ0txRHgrSzkwMjBoRHlvVnVDQis5NlpSTEtodW5YTXRPeGNRMWM4Nk14?=
 =?utf-8?B?QWM3UEpYWWZ3OVFoZXRUZWxyZmVXNDE5ZGlDQTJiY1dEVm91WFFYb0V1UVFu?=
 =?utf-8?B?N29nUm44eFYyZE1PSXNYRkt2QldrWlBac2ZNSllkemwzTTdhN3Y4NW45NUZp?=
 =?utf-8?B?QXZ4N2NUNDVlVERFcy9QTWd6TkFJWmxiKzF6TmhuZmRxcVZhY1U1emFMcUhy?=
 =?utf-8?Q?KYJhkcLgwFGmV7C9CzW/n+9xxUGCX9gQ6alpI6m?=
X-OriginatorOrg: suse.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 6ceb9de9-bca4-4c85-34ae-08d9840eb73c
X-MS-Exchange-CrossTenant-AuthSource: VI1PR04MB5600.eurprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Sep 2021 12:34:58.9369
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: f7a17af6-1c5c-4a36-aa8b-f5be247aa4ba
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: MTCCM6GdL4RD5oKcxgFMrJJWni9iY3k6Cc66Fcm16BqN2uOyT8Q+giH0k25AdM9GSW7VfEOWDYcRVjjYFIxMLw==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: VE1PR04MB6383
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

In preparation for restoring xen_set_pte_init()'s original behavior of
avoiding hypercalls, make set_pte_mfn() no longer use the standard
set_pte() code path. That one is more complicated than the alternative
of simply using an available hypercall directly. This way we can avoid
introducing a fair number (2k on my test system) of cases where the
hypervisor would trap-and-emulate page table updates.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -241,9 +241,11 @@ static void xen_set_pmd(pmd_t *ptr, pmd_
  * Associate a virtual page frame with a given physical page frame
  * and protection flags for that frame.
  */
-void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
+void __init set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
 {
-	set_pte_vaddr(vaddr, mfn_pte(mfn, flags));
+	if (HYPERVISOR_update_va_mapping(vaddr, mfn_pte(mfn, flags),
+					 UVMF_INVLPG))
+		BUG();
 }
 
 static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval)