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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 2A9E9C433F5 for ; Tue, 4 Jan 2022 17:11:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=9jvN/FHKb5b5ZgO+9KcuFeay8VUcWsugq2Nxx1Wrgak=; b=p6ZVAAJ82AUw11 JB3+vcJ5put2x0fWoZ4pgXXxmcBX5auzRH/2jxYMpiPu/Z7tI2grRtPmdDu/kQeg2JzeP6kj79dXy lKYlGJ7UahgWwyVFFfk4JJ2Pb1zuEXVBKBvuYAn1zuQBUK6SlAqCo6z1CLCcxfLIWW+z8epaDpi3T XLrT7w+NT+etgaI9IMOIwNdhbFGAbCC/Q/eZ0eTO5nQaiJgdpewmDXAtIxXeVBCIXadToJPL/Pq+f oF64ViFWZo5KnBsv2uHMooV+29O1hz2HnGxtgDmJVh1TVDhl+Zo9UNWuvMPjWyD0OzqdZnMA6BJDk MvTCg4pU8on/JWsM3XPg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1n4nK8-00CMIU-QE; Tue, 04 Jan 2022 17:10:13 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1n4nK4-00CMHA-FK for linux-arm-kernel@lists.infradead.org; Tue, 04 Jan 2022 17:10:10 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1641316205; 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=PLTIaY5gg/CGkjyFI0nVD1Ynp1qrSv98dwVoxTGL/gk=; b=AJW0duqdvpbTpNkkJJBxxZay8mHvtWn+4v0iQjIkvZi9YAb6hK0/S6XFzVUI7df99hSsn8 8277Of9jev/146U9Q4n5RnY1SNlZYnbVV0T2B5GvD22qVhdBPw5kfaMEu8pJ2sZ0aZLoBJ d1+KF6U9RBMMiAU2HKyjQKbzaDmZwgA= 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=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-673-ztyTry3YM8yhp5000m0kXg-1; Tue, 04 Jan 2022 12:10:04 -0500 X-MC-Unique: ztyTry3YM8yhp5000m0kXg-1 Received: by mail-ed1-f69.google.com with SMTP id x19-20020a05640226d300b003f8b80f5729so24458025edd.13 for ; Tue, 04 Jan 2022 09:10:03 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=PLTIaY5gg/CGkjyFI0nVD1Ynp1qrSv98dwVoxTGL/gk=; b=1QcR2rTxhhstpbWAIT35IlYHGXa0hLy3QRH94WBIW1S054HmKjZ8CCA29ZvqUY7y1X t/OyondX+o8COkwR37XQtWf7jMq+tt7mKmk679pEj/wjbFLK1xxcFGJA4rob9ooAlNLU Z51VhCruiMAILkz5cnmBQgI4jmiL1y4WltGBa3YTGGakciYIO3f35/lPChilNEG2c88Q vEdKrd9NVr3951lkha0GdfMmPON3O4ORyo7tmdy811LA3YinG5rU0W/JAONPLuUHpKqn R0J3c6SjtYQTuLxBCh3PrAgN4u2ZE99VfdAwBSTd2iANjA4SvsuUgooMfXzuxa/tMS3c xHmg== X-Gm-Message-State: AOAM531FXXD6aFoFIYaFPN0T8Drn+5jANeN5Grjr1RaskSJ3TRb3tDuU EENUeDNZhiwGP5UeVeBVv8dJLap2YjomD5QkUWzifwDQ6P7/fskkQLg1BegaTyyQbLcS0tApikW OPPeRbF37o+qdEvMkhwk4dAQ144gbzqqTeqE= X-Received: by 2002:a17:906:9f01:: with SMTP id fy1mr6911393ejc.475.1641316202908; Tue, 04 Jan 2022 09:10:02 -0800 (PST) X-Google-Smtp-Source: ABdhPJzg4c8oC/snOnarWsLYe2OuhHx3dyq7Vui9X2KCh4F+Gwu3wSidctLFczPe7rbJzItTjhvIEQ== X-Received: by 2002:a17:906:9f01:: with SMTP id fy1mr6911372ejc.475.1641316202670; Tue, 04 Jan 2022 09:10:02 -0800 (PST) Received: from ?IPV6:2001:b07:6468:f312:5e2c:eb9a:a8b6:fd3e? ([2001:b07:6468:f312:5e2c:eb9a:a8b6:fd3e]) by smtp.googlemail.com with ESMTPSA id w17sm14932963edu.48.2022.01.04.09.07.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 04 Jan 2022 09:10:02 -0800 (PST) Message-ID: Date: Tue, 4 Jan 2022 18:07:32 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 Subject: Re: Possible nohz-full/RCU issue in arm64 KVM To: Mark Rutland Cc: Nicolas Saenz Julienne , paulmck , maz , frederic , linux-kernel , rcu , Thomas Gleixner , Will Deacon , kvmarm@lists.cs.columbia.edu, linux-arm-kernel , Anup Patel References: <70f112072d9496d21901946ea82832d3ed3a8cb2.camel@redhat.com> <9ab8107f-ff41-6a9e-57e1-a261bea93aca@redhat.com> From: Paolo Bonzini In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pbonzini@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220104_091008_645797_C76FA6F0 X-CRM114-Status: GOOD ( 12.78 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 1/4/22 17:39, Mark Rutland wrote: > My main issue here was just that it's really difficult to see how the > entry/exit logic is balanced, and I reckon we can solve that by splitting > guest_{enter,exit}_irqoff() into helper functions to handle the vtime > accounting separately from the context tracking, so that arch code can do > something like: > > guest_timing_enter_irqoff(); > > guest_eqs_enter_irqoff(); > < actually run vCPU here > > guest_eqs_exit_irqoff(); > > < handle pending IRQs here > > > guest_timing_exit_irqoff(); > > ... which I hope should work for RISC-V too. > > I've had a go, and I've pushed out a WIP to: > > https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/kvm/rcu Yes, you have a point and it makes sense for x86 too. You can send me a topic branch once you get all the acks. Thanks! Paolo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel