From patchwork Thu Sep 14 04:47:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Xin3" X-Patchwork-Id: 13384571 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 33059EDE980 for ; Thu, 14 Sep 2023 05:34:44 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.601942.938328 (Exim 4.92) (envelope-from ) id 1qgezr-00021H-TV; Thu, 14 Sep 2023 05:34:35 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 601942.938328; Thu, 14 Sep 2023 05:34:35 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qgezr-00021A-QQ; Thu, 14 Sep 2023 05:34:35 +0000 Received: by outflank-mailman (input) for mailman id 601942; Thu, 14 Sep 2023 05:34:34 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qgelH-0001X7-Eo for xen-devel@lists.xenproject.org; Thu, 14 Sep 2023 05:19:31 +0000 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.65]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id 482bd31d-52be-11ee-8787-cb3800f73035; Thu, 14 Sep 2023 07:19:30 +0200 (CEST) Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Sep 2023 22:17:43 -0700 Received: from unknown (HELO fred..) ([172.25.112.68]) by orsmga001.jf.intel.com with ESMTP; 13 Sep 2023 22:17:42 -0700 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: 482bd31d-52be-11ee-8787-cb3800f73035 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1694668770; x=1726204770; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=FcZc1QeKj2isPTwOBVaGNTy+si5WeOaciLFU4yv7EQo=; b=mQELh168oyoE8sL+D7H9Xji/wkhViCObf6CpsxfAZy2XWs92/l+N8clv bOFx+n9zjMblyj3wICxUo+ALkTyVwPcgh64llM+ziIG8j7gUgYyOFHwlZ +BMLSQH4ii8WlWdj9LRRavGlH8DKIivYTdzPePmF+TFlWyJtOu1f4k20E pf1U7LwYZeWnhWUED4bt1RrOIOi5tSfrnWIcDZFOnzJlOX9YsqDMS+H5l sRqbnelL6eN69QLGEeGJZeE0jI5aFt+cKMVESZzJnn9ErPAguw/FXKZIr vvcEVCqKNF22q9+XPoING+q3wsndMhjaUIIMzb/5Le35p1XTqWnz2P0qd A==; X-IronPort-AV: E=McAfee;i="6600,9927,10832"; a="382661408" X-IronPort-AV: E=Sophos;i="6.02,145,1688454000"; d="scan'208";a="382661408" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10832"; a="779488817" X-IronPort-AV: E=Sophos;i="6.02,145,1688454000"; d="scan'208";a="779488817" From: Xin Li To: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, luto@kernel.org, pbonzini@redhat.com, seanjc@google.com, peterz@infradead.org, jgross@suse.com, ravi.v.shankar@intel.com, mhiramat@kernel.org, andrew.cooper3@citrix.com, jiangshanlai@gmail.com Subject: [PATCH v10 26/38] x86/fred: Add a NMI entry stub for FRED Date: Wed, 13 Sep 2023 21:47:53 -0700 Message-Id: <20230914044805.301390-27-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230914044805.301390-1-xin3.li@intel.com> References: <20230914044805.301390-1-xin3.li@intel.com> MIME-Version: 1.0 From: "H. Peter Anvin (Intel)" On a FRED system, NMIs nest both with themselves and faults, transient information is saved into the stack frame, and NMI unblocking only happens when the stack frame indicates that so should happen. Thus, the NMI entry stub for FRED is really quite small... Signed-off-by: H. Peter Anvin (Intel) Tested-by: Shan Kang Signed-off-by: Xin Li --- arch/x86/kernel/nmi.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index a0c551846b35..58843fdf5cd0 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -34,6 +34,7 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include @@ -643,6 +644,33 @@ void nmi_backtrace_stall_check(const struct cpumask *btp) #endif +#ifdef CONFIG_X86_FRED +/* + * With FRED, CR2/DR6 is pushed to #PF/#DB stack frame during FRED + * event delivery, i.e., there is no problem of transient states. + * And NMI unblocking only happens when the stack frame indicates + * that so should happen. + * + * Thus, the NMI entry stub for FRED is really straightforward and + * as simple as most exception handlers. As such, #DB is allowed + * during NMI handling. + */ +DEFINE_FREDENTRY_NMI(exc_nmi) +{ + irqentry_state_t irq_state; + + if (IS_ENABLED(CONFIG_SMP) && arch_cpu_is_offline(smp_processor_id())) + return; + + irq_state = irqentry_nmi_enter(regs); + + inc_irq_stat(__nmi_count); + default_do_nmi(regs); + + irqentry_nmi_exit(regs, irq_state); +} +#endif + void stop_nmi(void) { ignore_nmis++;