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 X-Spam-Level: X-Spam-Status: No, score=-5.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78CF7C4363A for ; Thu, 8 Oct 2020 14:28:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F2F721D41 for ; Thu, 8 Oct 2020 14:28:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="B1y4UgzM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730488AbgJHO17 (ORCPT ); Thu, 8 Oct 2020 10:27:59 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:22678 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729992AbgJHO17 (ORCPT ); Thu, 8 Oct 2020 10:27:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1602167278; 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: in-reply-to:in-reply-to:references:references; bh=2DqGTurTSdnreVGrCWwogl9N4t6aIEaM1wwUSTbToDg=; b=B1y4UgzMp6qtWodUFvxOZmlKCZpJtYJ1LPsEgG/UZDNf+plQLJWvoW7CWpzcxiAVImbpiG TnE8mi1I7ogZbXhHiioA4Li+NmgSeQmJ9EwJnIv0t5TZayh2vDGU2sVokr0ZaWnDpvLGTG fmKZh7jqhTM3M3dNZgLINB+u1Wbhp0I= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-306-WtrUfIQSO--Kp-9O1ho9Pg-1; Thu, 08 Oct 2020 10:27:56 -0400 X-MC-Unique: WtrUfIQSO--Kp-9O1ho9Pg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 89413191E2AF; Thu, 8 Oct 2020 14:27:55 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.40.192.132]) by smtp.corp.redhat.com (Postfix) with SMTP id 1A42B6EF63; Thu, 8 Oct 2020 14:27:53 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Thu, 8 Oct 2020 16:27:55 +0200 (CEST) Date: Thu, 8 Oct 2020 16:27:53 +0200 From: Oleg Nesterov To: Jens Axboe Cc: linux-kernel@vger.kernel.org, io-uring@vger.kernel.org, peterz@infradead.org, tglx@linutronix.de Subject: Re: [PATCH 4/6] kernel: add support for TIF_NOTIFY_SIGNAL Message-ID: <20201008142752.GI9995@redhat.com> References: <20201005150438.6628-1-axboe@kernel.dk> <20201005150438.6628-5-axboe@kernel.dk> <20201008135325.GG9995@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 10/08, Jens Axboe wrote: > > On 10/8/20 7:53 AM, Oleg Nesterov wrote: > >> --- a/kernel/entry/kvm.c > >> +++ b/kernel/entry/kvm.c > >> @@ -8,6 +8,9 @@ static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu, unsigned long ti_work) > >> do { > >> int ret; > >> > >> + if (ti_work & _TIF_NOTIFY_SIGNAL) > >> + tracehook_notify_signal(); > > > > Can't really comment this change, but to me it would be more safe to > > simply return -EINTR. > > > > Or perhaps even better, treat _TIF_NOTIFY_SIGNAL and _TIF_SIGPENDING > > equally: > > > > - if (ti_work & _TIF_SIGPENDING) { > > + if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) { > > kvm_handle_signal_exit(vcpu); > > return -EINTR; > > Not sure I follow your logic here. Why treat it any different than > NOTIFY_RESUME from this perspective? Ah, good point, I din't notice that xfer_to_guest_mode_work() handles TIF_NOTIFY_RESUME. Thanks, then I think this change is fine. Oleg.