From nobody Mon Feb 9 06:48:26 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass(p=none dis=none) header.from=sony.com ARC-Seal: i=1; a=rsa-sha256; t=1770026276; cv=none; d=zohomail.com; s=zohoarc; b=UzRaBLdF5sVdkx4GDV47PhKO3HNYJEoIc+xHsudi6sIZRkw+3ykGCG1IqtGQIIceiLzmnIvZxpMYtcOJ6xsEbkBj80CJqzE0eLp7XQDqzdXjFsLxq2Gxz/iRfW3ifSYscWSpIWJKc3BAUcbQGDt9cQSa3XHB74HlWPJpxFzNRCw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1770026276; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=4/LXZGnNgY5t+nsrdXbfktyTBcde00tw0WwNVU5EQeQ=; b=T6ZMJ1+0410sNrzkUS8JT6BdpJQz1bCdGY+eHmZ6y56E0zwcshkNYd0YyJEjv0w7YZsGkeRqL8zaMLoCEKB5qwxxkvRv+mif1GSQu3jCRD0WgQK7O7Cewi2HMchUHy12ZCdT1Ar9uMd/Vw+GChHlnZujJ1L1f0TcCGrLSYhYWYE= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1770026276723986.2414748420483; Mon, 2 Feb 2026 01:57:56 -0800 (PST) Received: from list by lists.xenproject.org with outflank-mailman.1218461.1527204 (Exim 4.92) (envelope-from ) id 1vmqgT-0001Z4-RW; Mon, 02 Feb 2026 09:57:29 +0000 Received: by outflank-mailman (output) from mailman id 1218461.1527204; Mon, 02 Feb 2026 09:57:29 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1vmqgT-0001YC-Od; Mon, 02 Feb 2026 09:57:29 +0000 Received: by outflank-mailman (input) for mailman id 1218461; Mon, 02 Feb 2026 09:52:02 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1vmqbB-0001Il-Vv for xen-devel@lists.xenproject.org; Mon, 02 Feb 2026 09:52:01 +0000 Received: from jpms-ob01.noc.sony.co.jp (jpms-ob01.noc.sony.co.jp [2001:cf8:ace:41::4]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id d121b1ab-001c-11f1-9ccf-f158ae23cfc8; Mon, 02 Feb 2026 10:51:59 +0100 (CET) Received: from unknown (HELO jpmta-ob1.noc.sony.co.jp) ([IPv6:2001:cf8:0:6e7::6]) by jpms-ob01.noc.sony.co.jp with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Feb 2026 18:51:38 +0900 Received: from unknown (HELO [127.0.1.1]) ([IPv6:2001:cf8:1:573:0:dddd:6b3e:119e]) by jpmta-ob1.noc.sony.co.jp with ESMTP; 02 Feb 2026 18:51:38 +0900 X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: d121b1ab-001c-11f1-9ccf-f158ae23cfc8 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sony.com; s=s1jp; t=1770025920; x=1801561920; h=from:date:subject:mime-version:content-transfer-encoding: message-id:references:in-reply-to:to:cc; bh=4/LXZGnNgY5t+nsrdXbfktyTBcde00tw0WwNVU5EQeQ=; b=nI6A7Ytwa1+zLh8IWECSnhLfuTcw4lqBn+HE9NyTzMST2ejWcv/0885i bTphFfjN08hVCUeoZAOE0EzeJREtl4uhiNSonsGqcqWEDvSz3lSXyl9il kCroDYD+AJfjEwynf9Os7NyNE4mOmUWHbpB8KhpFljpEoQbSqMerrIh04 AaQqpxAFGmxeBvSlpT0xL/QFwy8O0wGOZm9RTvk3W33wtQp+XJTOobQCv ez1PLsvIjuQ9BBALQdp0icSXXp7Vu6xil43egXNmHWYY/7WgCtdDnY9fZ l9V+C4CXNxlWqVzJ8EDWE4beYS17MnLNWhTjezCZmv9yyV7GDK60pIxfR g==; X-IronPort-AV: E=Sophos;i="6.21,268,1763391600"; d="scan'208";a="607384935" From: Shashank Balaji Date: Mon, 02 Feb 2026 18:51:02 +0900 Subject: [PATCH 1/3] x86/x2apic: disable x2apic on resume if the kernel expects so MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260202-x2apic-fix-v1-1-71c8f488a88b@sony.com> References: <20260202-x2apic-fix-v1-0-71c8f488a88b@sony.com> In-Reply-To: <20260202-x2apic-fix-v1-0-71c8f488a88b@sony.com> To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Suresh Siddha , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Ajay Kaher , Alexey Makhalov , Broadcom internal kernel review list , Jan Kiszka , Paolo Bonzini , Vitaly Kuznetsov , Juergen Gross , Boris Ostrovsky Cc: Ingo Molnar , linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, virtualization@lists.linux.dev, jailhouse-dev@googlegroups.com, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, Rahul Bukte , Shashank Balaji , Daniel Palmer , Tim Bird , stable@vger.kernel.org X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=1476; i=shashank.mahadasyam@sony.com; h=from:subject:message-id; bh=paULGXp6rwtbR4pGaBXqE9RYtLD7iRkEUs2lKCF5e4o=; b=owGbwMvMwCU2bX1+URVTXyjjabUkhsyG4hUGCzw4VzFOfPGnVC7+kcNGzhiLW3NYOT9WyZ0Rv y9psSK2o5SFQYyLQVZMkaVUqfrX3hVBS3rOvFaEmcPKBDKEgYtTACaytoXhv9Nrfese5QfJMkqT Qxp2Whn+q/TjDzf7xqHB/8O9W3/eVob/iW1Xy2aecbmXM6u73+ju1V8pak2+7/wsF/ZYNW4wOtz NCwA= X-Developer-Key: i=shashank.mahadasyam@sony.com; a=openpgp; fpr=75227BFABDA852A48CCCEB2196AF6F727A028E55 X-ZohoMail-DKIM: pass (identity @sony.com) X-ZM-MESSAGEID: 1770026278522158500 In lapic_resume, ensure x2apic is actually disabled when the kernel expects= it to be disabled, i.e. when x2apic_mode =3D 0. x2apic_mode is set to 0 and x2apic is disabled on boot if the kernel doesn't support irq remapping or for other reasons. On resume from s2ram (/sys/power/mem_sleep =3D deep), firmware can re-enable x2apic, but the ker= nel continues using the xapic interface because it didn't check to see if someo= ne enabled x2apic behind its back, which causes hangs. This situation happens = on defconfig + bare metal + s2ram, on which this fix has been tested. Fixes: 6e1cb38a2aef ("x64, x2apic/intr-remap: add x2apic support, including= enabling interrupt-remapping") Cc: stable@vger.kernel.org Co-developed-by: Rahul Bukte Signed-off-by: Rahul Bukte Signed-off-by: Shashank Balaji --- arch/x86/kernel/apic/apic.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index d93f87f29d03..cc64d61f82cf 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2456,6 +2456,12 @@ static void lapic_resume(void *data) if (x2apic_mode) { __x2apic_enable(); } else { + /* + * x2apic may have been re-enabled by the + * firmware on resuming from s2ram + */ + __x2apic_disable(); + /* * Make sure the APICBASE points to the right address * --=20 2.43.0