From nobody Mon Feb 9 07:23:46 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=quarantine dis=none) header.from=suse.com ARC-Seal: i=1; a=rsa-sha256; t=1605186898; cv=none; d=zohomail.com; s=zohoarc; b=CPwyDbIfeiIHgJO7JGG4nyTBnkurXf5b6q5yqztP/80exe+xiqxFJ3ixKLC38QEpO6Pz0cBwmlg6lv9/UXlugUIIxoy/x6+TjD7JVOtdFX4MGVQcKXUDShek3w8SXkk9bbCxL/H1Qnxh8DIzkDGhE5nE9Weu+AiCGcPwtgdli7s= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1605186898; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=zktMZTHwnyh8KDaewloiOYrp8NVJ08f3acWn1GTzuRQ=; b=M1lprruXNjrRPfjD/BlcHI2u5Revd2wwBVunN/NnAOQpYNcS1MYS7+I2eSXV8EWHWgyIaZdz+2rdKg07lNCyV4moVC+KHt0n00UJgOpUqppCoPS1WWW2aksrL41x+DYuP+hwg2X32ViB6wgieGAIlghPWyKNkwC3+yUpDapuM/0= 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=quarantine dis=none) header.from= Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1605186898786902.4426447720842; Thu, 12 Nov 2020 05:14:58 -0800 (PST) Received: from list by lists.xenproject.org with outflank-mailman.25847.53906 (Exim 4.92) (envelope-from ) id 1kdCQx-00068s-U2; Thu, 12 Nov 2020 13:14:39 +0000 Received: by outflank-mailman (output) from mailman id 25847.53906; Thu, 12 Nov 2020 13:14:39 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kdCQx-00068j-PT; Thu, 12 Nov 2020 13:14:39 +0000 Received: by outflank-mailman (input) for mailman id 25847; Thu, 12 Nov 2020 13:14:38 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kdCQw-0005zc-Lh for xen-devel@lists.xenproject.org; Thu, 12 Nov 2020 13:14:38 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 8df1d582-b3fc-4503-9774-fc9fc284423b; Thu, 12 Nov 2020 13:14:27 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id E34EDAC75; Thu, 12 Nov 2020 13:14:26 +0000 (UTC) Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kdCQw-0005zc-Lh for xen-devel@lists.xenproject.org; Thu, 12 Nov 2020 13:14:38 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 8df1d582-b3fc-4503-9774-fc9fc284423b; Thu, 12 Nov 2020 13:14:27 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id E34EDAC75; Thu, 12 Nov 2020 13:14:26 +0000 (UTC) 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: 8df1d582-b3fc-4503-9774-fc9fc284423b X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1605186867; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zktMZTHwnyh8KDaewloiOYrp8NVJ08f3acWn1GTzuRQ=; b=bwAv/CKwTJZpEl6+vBsDSeyO95J4zYnx4pm7vVM4JqM0x8OBmK9YXUTY2gKvlwrZFQy+MR OQQSn4+piHpPWQPoy2QctIrKrU/Xv3JMn1xXvdj7gPdEnc6IlWZHQoM7tpytZaUeZrjPh6 BHC4IJtPNJ7lTEJY6jKRTFiczBDcpU8= From: Juergen Gross To: xen-devel@lists.xenproject.org Cc: Juergen Gross , Jan Beulich , Andrew Cooper , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= , Wei Liu Subject: [PATCH v5 1/3] xen/x86: add nmi continuation framework Date: Thu, 12 Nov 2020 14:14:22 +0100 Message-Id: <20201112131424.9930-2-jgross@suse.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201112131424.9930-1-jgross@suse.com> References: <20201112131424.9930-1-jgross@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @suse.com) Actions in NMI context are rather limited as e.g. locking is rather fragile. Add a framework to continue processing in normal interrupt context after leaving NMI processing. This is done by a high priority interrupt vector triggered via a self IPI from NMI context, which will then call the continuation function specified during NMI handling. Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich --- V5: - add comment (Jan Beulich) V4: - make the framework less generic V2: - add prototype for continuation function (Roger Pau Monn=C3=A9) - switch from softirq to explicit self-IPI (Jan Beulich) Signed-off-by: Juergen Gross --- xen/arch/x86/apic.c | 13 ++++++++++--- xen/arch/x86/genapic/x2apic.c | 1 + xen/arch/x86/smp.c | 1 + xen/arch/x86/traps.c | 21 +++++++++++++++++++++ xen/include/asm-x86/nmi.h | 11 ++++++++++- 5 files changed, 43 insertions(+), 4 deletions(-) diff --git a/xen/arch/x86/apic.c b/xen/arch/x86/apic.c index 60627fd6e6..7497ddb5da 100644 --- a/xen/arch/x86/apic.c +++ b/xen/arch/x86/apic.c @@ -40,6 +40,7 @@ #include #include #include +#include #include =20 static bool __read_mostly tdt_enabled; @@ -1376,16 +1377,22 @@ void spurious_interrupt(struct cpu_user_regs *regs) { /* * Check if this is a vectored interrupt (most likely, as this is prob= ably - * a request to dump local CPU state). Vectored interrupts are ACKed; - * spurious interrupts are not. + * a request to dump local CPU state or to continue NMI handling). + * Vectored interrupts are ACKed; spurious interrupts are not. */ if (apic_isr_read(SPURIOUS_APIC_VECTOR)) { + bool is_spurious; + ack_APIC_irq(); + is_spurious =3D !nmi_check_continuation(); if (this_cpu(state_dump_pending)) { this_cpu(state_dump_pending) =3D false; dump_execstate(regs); - return; + is_spurious =3D false; } + + if ( !is_spurious ) + return; } =20 /* see sw-dev-man vol 3, chapter 7.4.13.5 */ diff --git a/xen/arch/x86/genapic/x2apic.c b/xen/arch/x86/genapic/x2apic.c index 077a576a7f..40284b70d1 100644 --- a/xen/arch/x86/genapic/x2apic.c +++ b/xen/arch/x86/genapic/x2apic.c @@ -89,6 +89,7 @@ static unsigned int cpu_mask_to_apicid_x2apic_cluster(con= st cpumask_t *cpumask) =20 static void send_IPI_self_x2apic(uint8_t vector) { + /* NMI continuation handling relies on using a shorthand here. */ apic_wrmsr(APIC_SELF_IPI, vector); } =20 diff --git a/xen/arch/x86/smp.c b/xen/arch/x86/smp.c index 14aa355a6b..eef0f9c6cb 100644 --- a/xen/arch/x86/smp.c +++ b/xen/arch/x86/smp.c @@ -163,6 +163,7 @@ void send_IPI_self(int vector) =20 void send_IPI_self_legacy(uint8_t vector) { + /* NMI continuation handling relies on using a shorthand here. */ send_IPI_shortcut(APIC_DEST_SELF, vector, APIC_DEST_PHYSICAL); } =20 diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c index c27dd4cd43..5cbaa49031 100644 --- a/xen/arch/x86/traps.c +++ b/xen/arch/x86/traps.c @@ -79,6 +79,7 @@ #include #include #include +#include #include #include =20 @@ -1800,6 +1801,26 @@ void unset_nmi_callback(void) nmi_callback =3D dummy_nmi_callback; } =20 +bool nmi_check_continuation(void) +{ + bool ret =3D false; + + return ret; +} + +void trigger_nmi_continuation(void) +{ + /* + * Issue a self-IPI. Handling is done in spurious_interrupt(). + * NMI could have happened in IPI sequence, so wait for ICR being idle + * again before leaving NMI handler. + * This relies on self-IPI using a simple shorthand, thus avoiding any + * use of locking or percpu cpumasks. + */ + send_IPI_self(SPURIOUS_APIC_VECTOR); + apic_wait_icr_idle(); +} + void do_device_not_available(struct cpu_user_regs *regs) { #ifdef CONFIG_PV diff --git a/xen/include/asm-x86/nmi.h b/xen/include/asm-x86/nmi.h index a288f02a50..9a5da14162 100644 --- a/xen/include/asm-x86/nmi.h +++ b/xen/include/asm-x86/nmi.h @@ -33,5 +33,14 @@ nmi_callback_t *set_nmi_callback(nmi_callback_t *callbac= k); void unset_nmi_callback(void); =20 DECLARE_PER_CPU(unsigned int, nmi_count); -=20 + +/** + * trigger_nmi_continuation + * + * Schedule continuation to be started in interrupt context after NMI hand= ling. + */ +void trigger_nmi_continuation(void); + +/* Check for NMI continuation pending. */ +bool nmi_check_continuation(void); #endif /* ASM_NMI_H */ --=20 2.26.2