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 682F1C433FE for ; Wed, 30 Nov 2022 17:04:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231157AbiK3RE0 (ORCPT ); Wed, 30 Nov 2022 12:04:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54226 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231137AbiK3RDi (ORCPT ); Wed, 30 Nov 2022 12:03:38 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 70C12900EF for ; Wed, 30 Nov 2022 08:59:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1669827541; 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=m9a6wFc0RaDwZ5W3tObwtvd4DevYG79SiLdXsbs2flM=; b=RkwMdPiGfWGRRqlZgMWCo/c6EwlhsfI+5qapUN/ED/vT+tou+0fM1VvaDCo+R5F7WOH5sT EApABchB7Iry/e+PzqEFA8kh2T/3AMfcTGXvE3+3mZsGHXUNwVcWo1eBsQTbd50VV05iQ2 6+zFR0YB3brEqvMSLAJzLvLma91aa7I= Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-88-TOT6T7w0MdWwGxTjMz2j0A-1; Wed, 30 Nov 2022 11:58:59 -0500 X-MC-Unique: TOT6T7w0MdWwGxTjMz2j0A-1 Received: by mail-ed1-f69.google.com with SMTP id f17-20020a056402355100b00466481256f6so10092861edd.19 for ; Wed, 30 Nov 2022 08:58:59 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=m9a6wFc0RaDwZ5W3tObwtvd4DevYG79SiLdXsbs2flM=; b=y7Nc0cnUzIvnh3qZnnkIG2FZVqLbEb0VgO3Sp4tqu03FsNA8+/Yj8JRlt0D5Z/eOt6 BCwV4MebgYS2CNiq00H4s8SYkigXM61SogTATNKJaI9vaUaiHQMDreT/ZQ2J9Bp1uRNe HTJ6qsj5tfmQuJG8YqbBHo/QF8JOkIR3069uIkPif4p1uaCkF6Yn28B/gvT+FmXfKWPD EgzvgpdqVSNqvLDUNMS9jKTkiBeT/+qelEj6W56zVJ8cWHaq8HnFy2+m9XYfaRBWvEui evnxl5Wtes4TPo60U+h/z1Asvx7KR0StH4AIm+4rCOtRuIYUWg5rHZATPIDpLgSmaOfJ pSwA== X-Gm-Message-State: ANoB5pm9QuA80glBxRmJTIumh9RJ010OO8OqT7SSJf+6LraI+icOZOc+ PcYLvkc4kyUkHi2a5ePEMa05tbgaoBnddgJCuxJpnKYbCR/qhdG5bdnIQZU2XHBmQfmfT9cpDXw iKdNaAfEFmJGOrnn/gBHMH7tm X-Received: by 2002:a17:907:7784:b0:7ad:9ad7:e882 with SMTP id ky4-20020a170907778400b007ad9ad7e882mr39488590ejc.520.1669827537829; Wed, 30 Nov 2022 08:58:57 -0800 (PST) X-Google-Smtp-Source: AA0mqf73qL1Jhq523BYbZhmApLx4RduRu+6qDZGDKtgYCMtGXyWkWoUIgRl5EweEwMB+7nAWZtnqqw== X-Received: by 2002:a17:907:7784:b0:7ad:9ad7:e882 with SMTP id ky4-20020a170907778400b007ad9ad7e882mr39488574ejc.520.1669827537573; Wed, 30 Nov 2022 08:58:57 -0800 (PST) Received: from ?IPV6:2001:b07:6468:f312:4783:a68:c1ee:15c5? ([2001:b07:6468:f312:4783:a68:c1ee:15c5]) by smtp.googlemail.com with ESMTPSA id gi20-20020a1709070c9400b0077d6f628e14sm847674ejc.83.2022.11.30.08.58.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 30 Nov 2022 08:58:56 -0800 (PST) Message-ID: Date: Wed, 30 Nov 2022 17:58:56 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 Subject: Re: [PATCH] KVM: Deal with nested sleeps in kvm_vcpu_block() Content-Language: en-US To: Space Meyer , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: kpsingh@kernel.org References: <20221130161946.3254953-1-spm@google.com> From: Paolo Bonzini In-Reply-To: <20221130161946.3254953-1-spm@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/30/22 17:19, Space Meyer wrote: > bool kvm_vcpu_block(struct kvm_vcpu *vcpu) > { > + DEFINE_WAIT_FUNC(vcpu_block_wait, woken_wake_function); > struct rcuwait *wait = kvm_arch_vcpu_get_wait(vcpu); > bool waited = false; > > @@ -3437,13 +3439,11 @@ bool kvm_vcpu_block(struct kvm_vcpu *vcpu) > preempt_enable(); > > for (;;) { > - set_current_state(TASK_INTERRUPTIBLE); > - > if (kvm_vcpu_check_block(vcpu) < 0) > break; > > waited = true; > - schedule(); > + wait_woken(&vcpu_block_wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); > } Also, this does not work I think, because there is add_wait_queue()/remove_wait_queue() pair. Adding it is not easy because KVM is using a struct rcuwait here instead of a wait_queue_t. Paolo