Received-SPF: pass (google.com: domain of linux-kernel+bounces-24606-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
From: =?iso-2022-jp?B?Tk9NVVJBIEpVTklDSEkoGyRCTG5CPCEhPV8wbBsoQik=?=
	<junichi.nomura@nec.com>
To: "mingo@redhat.com" <mingo@redhat.com>, "tglx@linutronix.de"
	<tglx@linutronix.de>, "bp@alien8.de" <bp@alien8.de>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>, "x86@kernel.org"
	<x86@kernel.org>
CC: "hpa@zytor.com" <hpa@zytor.com>, "kirill.shutemov@linux.intel.com"
	<kirill.shutemov@linux.intel.com>, "ardb@kernel.org" <ardb@kernel.org>,
	"david@redhat.com" <david@redhat.com>, "nikunj@amd.com" <nikunj@amd.com>,
	"thomas.lendacky@amd.com" <thomas.lendacky@amd.com>, "debarbos@redhat.com"
	<debarbos@redhat.com>, "jlelli@redhat.com" <jlelli@redhat.com>,
	"lgoncalv@redhat.com" <lgoncalv@redhat.com>, "dzickus@redhat.com"
	<dzickus@redhat.com>, "linux-kernel@vger.kernel.org"
	<linux-kernel@vger.kernel.org>
Subject: [PATCH repost] x86/boot: Add a message about ignored early NMIs
Thread-Topic: [PATCH repost] x86/boot: Add a message about ignored early NMIs
Thread-Index: AQHaRUhttMsB94tJmUuDDAl0tLENcQ==
Date: Fri, 12 Jan 2024 11:13:53 +0000
Message-ID: <ZaEe8FC767f+sxRQ@jeru.linux.bs1.fc.nec.co.jp>
Accept-Language: ja-JP, en-US
Content-Language: en-US
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0:
 =?iso-2022-jp?B?aTNQaFpxdW42U3JiZW9WSFBJbzVHU3dMWlhHKy9wNHlYeUttcUszRmts?=
 =?iso-2022-jp?B?c1l4RkdBV2ZGQ2pzS3Vjd2xxQUhGTEJRUXdTSkYyeXdlanR2RWJTUDVH?=
 =?iso-2022-jp?B?eUNJRHN1K0tIY1FJTjgybFNybUpRelNaWUQzbFFuS3ZRQWFKZWpxWk5Q?=
 =?iso-2022-jp?B?eHJzKzJmOWxoTjJHdGVjOHVrY0wvZDIwOXVmZlBheTJMVUtqQllKKytY?=
 =?iso-2022-jp?B?TStlU1RlR3RZWWtOb2dBeCtwajVwak4vdzhKZW9QS2Q5UUxPWmNSYno2?=
 =?iso-2022-jp?B?T2MwL3BtMzY4QVREWSs4RkhoazRyMDBKK29KK2p0OHdUMjM3RytWbnIv?=
 =?iso-2022-jp?B?QnIydTR2dzFVN3RlTDdFUFpkVkRBL1FUZWFzUm9jWFd6aCtzaFIwUHVJ?=
 =?iso-2022-jp?B?ZSswak04UmlHeTZyYkJmUFBTWGJxVzNnM0l6L3NmL2xiN1NUN3pHSGU3?=
 =?iso-2022-jp?B?SW1NdURzVnh2MG90NkZ2SjNjVHF1UU93V1doSmlFS2ZGT2k4RkVNSHFt?=
 =?iso-2022-jp?B?cTJ3eDV4QVdLbXJ1RHA3Z3lveUpGbXFCLzRSMXNZOFZTNFgzSVcvb25Y?=
 =?iso-2022-jp?B?WGN0c0F3T1VYRG5kVHFPVzlUQVZua1k1UjY1Y2FTeW1VQVdHbFcvVDhG?=
 =?iso-2022-jp?B?UE5zS3RYQ3F1clBYbERhblVmREwraUxNUUthVHhnbkl1NXBqWG02ZENI?=
 =?iso-2022-jp?B?aWZacEZhSTVreTFveStWMTRUaXZEWUJWR2ZKRlY0Y2N4L1NuRER0bGZy?=
 =?iso-2022-jp?B?NGFqVE9Ya0xYM2ZQMEF2U1kzNWRLNUd0NDV0bHRyQWVtVzI1ZEE5VE16?=
 =?iso-2022-jp?B?eFNuNkVzQXZpKy92R1lRMFpBVE5vZXVreEJyRzN6VUM2ZFFZdFBid3Vy?=
 =?iso-2022-jp?B?UVZHVmphdUJZbGxwUWFOZ2drbE9NVGk3OTRNVTlSaWpMN3NKRVNtdU5P?=
 =?iso-2022-jp?B?R0dBREZVblhjOUY2SHJBSlNoTngzRmdSalJHVDdFcDh2Rno0Y3JKS1Jv?=
 =?iso-2022-jp?B?SXlUR3FYYXp5WTczbUF2dlV0NEh4Q3BNQnB5aVFzZTZhc3AyNlJRWGRM?=
 =?iso-2022-jp?B?ZFVrM3RnNWpscVlWT1R3RUtXQktzQjhCVkpyVkY3L3lCTlBUcWVKdUdk?=
 =?iso-2022-jp?B?bzJROW1iT0V1aml6ZEFqcEZuZit4Z0ZIYmpIY0xmU0RKMzFkQUJaVWZo?=
 =?iso-2022-jp?B?ZTVXTnp3SlZaMkNaTzJyVVAvVlBDdHRFUlE4SktJaXRkQnpUZVUycjND?=
 =?iso-2022-jp?B?QmQxbTV4QmhOOUVpVVQ4cGtRM3pnY21oSVZYMlJCUDZiVFp3MXNrOHNR?=
 =?iso-2022-jp?B?TWxHTXhMOHdac2NObVZhaXE5WDJLSndTN2JYYmk4SGJpaWpSeWFmQXZr?=
 =?iso-2022-jp?B?MGtERGNLOFN1V3A3bnptVjluTDZweXovbEJIcHpwZkdZU1JCNlV6anhp?=
 =?iso-2022-jp?B?d0tVYTNTbzB0RFc1QjIwdnlITW9JRjliQVlialovZmYzelhEWTZsbWlG?=
 =?iso-2022-jp?B?ZGlPUFFUMlNmNkpQTnpMc1RMdHlBN29iVFBJLzI1cnl3WDNsd0lPTlla?=
 =?iso-2022-jp?B?emo5ZEpoTExlQzh1ZWd2QmFzcGpVbzMxMGwrQVpnUFluUUwybWJZdlFu?=
 =?iso-2022-jp?B?SkpRWVA0bzVCMTZPcUNaV29rV3JabDhBL2FSTzRSaTlUSkdVM2c4VWM4?=
 =?iso-2022-jp?B?MDRqK2doMW1nL0EvSTVtMy9MM0s5ZzgvVXZOeHlRQ2hMdlZEa1lGakxU?=
 =?iso-2022-jp?B?eGk0ZzRRYXZXUS9HaTdMeHc1NnBIWkNWTVNWU3lHY3c4Z0x0TFROVHFT?=
 =?iso-2022-jp?B?Q3NvalJlUlhEVCtrZnFuZi93aTRHYStUME9KK0NHRHIzTUJXQUlKUTFi?=
 =?iso-2022-jp?B?L3ByU28wc25NdUdnSk04RW9RY2VlN3ROeTVKVFpvaGZtTGk5dFIwS1g3?=
 =?iso-2022-jp?B?N2VrWHFONnZHZGpjYjZDYWV4eEhsMENSZGh1MDFXZFh4WmRTZmFQOEJo?=
 =?iso-2022-jp?B?ZHZ5eDlJT3hsUkJQSVVYVmhJajBFWTFQMkRlVGVsSlRFZ1doVTMvK3V6?=
 =?iso-2022-jp?B?ZTQ0TDYvR2RUY2UrOVB2b3lqMm9JSkRYZTlzQm1HSjJ0QWw3OHZzNmNk?=
 =?iso-2022-jp?B?ejNycGlBaFZOemN3VDJMc29QZ3JTM2pNRW9ET291bUhrYWdicG1IMndj?=
 =?iso-2022-jp?B?cXFvYUdTU29BWXh2VG90bzM0cVdyOWcyc2prQ0huMGNreG5nQkZqRXlq?=
 =?iso-2022-jp?B?U1pOOUs3N3BvekdMT25oVm9DdVRwV0JIaTlaTXJleGZrTmtyMExleGR1?=
 =?iso-2022-jp?B?dCtQSzc3ZlhrUEd5NUZrOU5qaHo5QmhGNFE9PQ==?=
Content-Type: text/plain; charset="iso-2022-jp"
Content-ID: <B3582B4D0C377F4788E999B4390C1252@jpnprd01.prod.outlook.com>
Content-Transfer-Encoding: quoted-printable
Precedence: bulk
X-Mailing-List: linux-kernel@vger.kernel.org
List-Id: <linux-kernel.vger.kernel.org>
List-Subscribe: <mailto:linux-kernel+subscribe@vger.kernel.org>
List-Unsubscribe: <mailto:linux-kernel+unsubscribe@vger.kernel.org>
MIME-Version: 1.0
X-OriginatorOrg: nec.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: TYCPR01MB8389.jpnprd01.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 37fcad32-6847-4ff9-e3b4-08dc135f8fb4
X-MS-Exchange-CrossTenant-originalarrivaltime: 12 Jan 2024 11:13:53.3153
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: e67df547-9d0d-4f4d-9161-51c6ed1f7d11
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: zSxWO8Z7c06z8ch4le93BZmGlKBCuWw+vv1qX+LxvGHcQji0jR7lwbnxyccVGRESxVNsQR7DQfkib5Rsz7zUCw==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: TYWPR01MB8696

Commit 78a509fba9c9 ("x86/boot: Ignore NMIs during very early boot") added
empty handler in early boot stage to avoid boot failure by spurious NMIs.

Add a diagnostic message in case we need to know whether early NMIs have
occurred and/or what happened to them.

Signed-off-by: Jun'ichi Nomura <junichi.nomura@nec.com>
Suggested-by: Borislav Petkov <bp@alien8.de>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Link: https://lore.kernel.org/lkml/20231130103339.GCZWhlA196uRklTMNF@fat_cr=
ate.local/

diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compre=
ssed/ident_map_64.c
--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -387,7 +387,10 @@ void do_boot_page_fault(struct pt_regs *regs, unsigned=
 long error_code)
 	kernel_add_identity_map(address, end);
 }
=20
+extern int spurious_nmi_count;
+
 void do_boot_nmi_trap(struct pt_regs *regs, unsigned long error_code)
 {
 	/* Empty handler to ignore NMI during early boot */
+	spurious_nmi_count++;
 }
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/mis=
c.c
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -357,6 +357,8 @@ unsigned long decompress_kernel(unsigned char *outbuf, =
unsigned long virt_addr,
 	return entry;
 }
=20
+int spurious_nmi_count;
+
 /*
  * The compressed kernel image (ZO), has been moved so that its position
  * is against the end of the buffer used to hold the uncompressed kernel
@@ -493,6 +495,12 @@ asmlinkage __visible void *extract_kernel(void *rmode,=
 unsigned char *output)
 	/* Disable exception handling before booting the kernel */
 	cleanup_exception_handling();
=20
+	if (spurious_nmi_count) {
+		error_putstr("Spurious early NMI ignored. Number of NMIs: 0x");
+		error_puthex(spurious_nmi_count);
+		error_putstr("\n");
+	}
+
 	return output + entry_offset;
 }
 =