From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A0CBC433F5 for ; Thu, 27 Jan 2022 17:26:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244527AbiA0R0v (ORCPT ); Thu, 27 Jan 2022 12:26:51 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:24918 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244546AbiA0R0q (ORCPT ); Thu, 27 Jan 2022 12:26:46 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1643304406; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc; bh=NXoYI30puVcZTE3uk6QqVni9m99qtUCC+GlZO0I0pdU=; b=M96OQnKWBjsl6BtaYnpyn86QvS8wqv2Ayu/TmcTdPyp66xc7/Fw3oV29sqZIGem3aPQ7y+ mo2dYpbtb23vwNnJzHRO0MX6pcIxlWg/MraPcQQiYOYGV6NZBM3HRYjNnHFS7VojjTRkmT /qTkT5jtPFjx1LT7FvXojTSA6TZwWTo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-638-S6jdvpCVPouic3isYVWYtQ-1; Thu, 27 Jan 2022 12:26:43 -0500 X-MC-Unique: S6jdvpCVPouic3isYVWYtQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AB25019251C7; Thu, 27 Jan 2022 17:26:41 +0000 (UTC) Received: from fuller.cnet (ovpn-112-4.gru2.redhat.com [10.97.112.4]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 66F3A74E96; Thu, 27 Jan 2022 17:26:29 +0000 (UTC) Received: by fuller.cnet (Postfix, from userid 1000) id A3A94417130B; Thu, 27 Jan 2022 14:26:05 -0300 (-03) Message-ID: <20220127172552.549322745@fuller.cnet> User-Agent: quilt/0.66 Date: Thu, 27 Jan 2022 14:23:27 -0300 From: Marcelo Tosatti To: linux-kernel@vger.kernel.org Cc: Nitesh Lal , Nicolas Saenz Julienne , Frederic Weisbecker , Christoph Lameter , Juri Lelli , Peter Zijlstra , Alex Belits , Peter Xu , Thomas Gleixner , Daniel Bristot de Oliveira , Marcelo Tosatti Subject: [patch v9 08/10] KVM: x86: process isolation work from VM-entry code path X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The logic to disable vmstat worker thread, when entering nohz full, does not cover all scenarios. For example, it is possible for the following to happen: References: <20220127172319.428529308@fuller.cnet> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 VM-entry code path is an entry point similar to userspace return when task isolation is concerned. Call isolation_exit_to_user_mode before VM-enter. Signed-off-by: Marcelo Tosatti --- include/linux/entry-kvm.h | 4 +++- kernel/entry/kvm.c | 18 ++++++++++++++---- 2 files changed, 17 insertions(+), 5 deletions(-) Index: linux-2.6/kernel/entry/kvm.c =================================================================== --- linux-2.6.orig/kernel/entry/kvm.c +++ linux-2.6/kernel/entry/kvm.c @@ -2,8 +2,11 @@ #include #include +#include -static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu, unsigned long ti_work) +static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu, + unsigned long ti_work, + unsigned long task_isol_work) { do { int ret; @@ -25,15 +28,19 @@ static int xfer_to_guest_mode_work(struc ret = arch_xfer_to_guest_mode_handle_work(vcpu, ti_work); if (ret) return ret; + if (task_isol_work) + task_isol_exit_to_user_mode(); ti_work = read_thread_flags(); - } while (ti_work & XFER_TO_GUEST_MODE_WORK || need_resched()); + } while (ti_work & XFER_TO_GUEST_MODE_WORK || need_resched() || + task_isol_work); return 0; } int xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu) { unsigned long ti_work; + unsigned long task_isol_work; /* * This is invoked from the outer guest loop with interrupts and @@ -44,9 +51,9 @@ int xfer_to_guest_mode_handle_work(struc * to disable interrupts here. */ ti_work = read_thread_flags(); - if (!(ti_work & XFER_TO_GUEST_MODE_WORK)) + if (!(ti_work & XFER_TO_GUEST_MODE_WORK) || task_isol_work) return 0; - return xfer_to_guest_mode_work(vcpu, ti_work); + return xfer_to_guest_mode_work(vcpu, ti_work, task_isol_work); } EXPORT_SYMBOL_GPL(xfer_to_guest_mode_handle_work); Index: linux-2.6/include/linux/entry-kvm.h =================================================================== --- linux-2.6.orig/include/linux/entry-kvm.h +++ linux-2.6/include/linux/entry-kvm.h @@ -8,6 +8,7 @@ #include #include #include +#include /* Transfer to guest mode work */ #ifdef CONFIG_KVM_XFER_TO_GUEST_WORK @@ -76,8 +77,9 @@ static inline void xfer_to_guest_mode_pr static inline bool __xfer_to_guest_mode_work_pending(void) { unsigned long ti_work = read_thread_flags(); + unsigned long task_isol_work = task_isol_has_work(); - return !!(ti_work & XFER_TO_GUEST_MODE_WORK); + return !!((ti_work & XFER_TO_GUEST_MODE_WORK) || task_isol_work); } /**