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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 7AE7EEED61E for ; Fri, 15 Sep 2023 18:54:59 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qhDxF-0008Ub-Ui; Fri, 15 Sep 2023 14:54:13 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qhDxD-0008UG-6B for qemu-devel@nongnu.org; Fri, 15 Sep 2023 14:54:11 -0400 Received: from mail-pg1-x535.google.com ([2607:f8b0:4864:20::535]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qhDxB-0005sB-MP for qemu-devel@nongnu.org; Fri, 15 Sep 2023 14:54:10 -0400 Received: by mail-pg1-x535.google.com with SMTP id 41be03b00d2f7-5657add1073so1811343a12.0 for ; Fri, 15 Sep 2023 11:54:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1694804048; x=1695408848; darn=nongnu.org; h=content-transfer-encoding:in-reply-to:content-language:references :cc:to:from:subject:user-agent:mime-version:date:message-id:from:to :cc:subject:date:message-id:reply-to; bh=RMHYMDweSIDEzd38f742fSSNn+Sn6GEZeco5jcEMZH8=; b=HEbkACHeN8FVVpIa7XIQFtkwkVOcBG2oUphwWoaXslOtguSFxPMVH+Vj5koqn84+MV 9ClFXDwrPV0+QcDgc/Pbwjc2NVG8l0HxXig0cOHiHomFZxpuB6qCmn2dAjivpaheVRZL q+PIRWWIr9Epd5N6fEgejcd9Yx7f2mxz6tQWfhwSFlhI1iNLAgskwTbIcjSQtPbu4fRd PbEilwmQtLZ1rTHY2JaAY7CE7EySnYE912DYRCfHif7cCfpoZ/yucTCFbI/ObZaiScoP bS0i8C74wLtIpjLyJhMRhmc+hb16c9z/yDnDYDT5K9asTCxcngohaoEurbW+S1o/jIhG XOPQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694804048; x=1695408848; h=content-transfer-encoding:in-reply-to:content-language:references :cc:to:from:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=RMHYMDweSIDEzd38f742fSSNn+Sn6GEZeco5jcEMZH8=; b=BFOk/UTMj39zLi4lrm4m6+zhTyAPX23LL8F84auR1UaJho3Lo/sFKPp+gWM6iogzUD hprwb8JiB1w/2LZG4R+t3Ciij5qmsAIRmXzfze1U8wtpcw3WGRS0VT2npriir7Pu/C/h 7iGr+FLHIbMEdXz5jm6MYcO+UT1l1wmShldCpqdhsJ904Sx0576qhSVdynyl6LxNgXCt S4iCF8E46AvX65bMvGbAoR2/l6CNIi6akwcmPAJ47bnfYl5IYEUqe2xKBoMLk5YIj+hW ZPJhk4EhVe12LtQWrfIUVRBzceJLWKsdFs6YlOBndq1rjNsbncY5xKLLbUFAs9j7REqN TwXw== X-Gm-Message-State: AOJu0YwyTZn00SYYWeZX4gL4UbSTJKvn+NJo5O8oGoneHqdw5amHofc6 9e78IW7Sm4Al1rZdDs/SN0miwnSni27lBY6DJAY= X-Google-Smtp-Source: AGHT+IES+88KqfXNxbM4KxS8Nxvy1Up/9NjcAgU/r5kQTSdugq5kSXh/l1ULHFxjBGHsysHTx71stw== X-Received: by 2002:a17:90a:a891:b0:273:ec82:5554 with SMTP id h17-20020a17090aa89100b00273ec825554mr3479878pjq.9.1694804047979; Fri, 15 Sep 2023 11:54:07 -0700 (PDT) Received: from [192.168.0.4] ([71.212.131.115]) by smtp.gmail.com with ESMTPSA id g23-20020a17090a579700b00268dac826d4sm3286052pji.0.2023.09.15.11.54.07 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 15 Sep 2023 11:54:07 -0700 (PDT) Message-ID: <2d2b9fca-94ae-8a8f-1380-35eedeadee13@linaro.org> Date: Fri, 15 Sep 2023 11:54:05 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Subject: Re: [PATCH v2 0/3] accel/tcg: Alternate fix for #1866 From: Richard Henderson To: qemu-devel@nongnu.org Cc: philmd@linaro.org References: <20230915163254.123338-1-richard.henderson@linaro.org> Content-Language: en-US In-Reply-To: <20230915163254.123338-1-richard.henderson@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::535; envelope-from=richard.henderson@linaro.org; helo=mail-pg1-x535.google.com X-Spam_score_int: -35 X-Spam_score: -3.6 X-Spam_bar: --- X-Spam_report: (-3.6 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-1.473, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 9/15/23 09:32, Richard Henderson wrote: > Supercedes: 20230914174436.1597356-1-richard.henderson@linaro.org > ("[PATCH 0/6] accel/tcg: Always require can_do_io (#1866)") > > An alternate fix for #1866 without touching can_do_io, and is > perhaps a bit cleaner and clearer. > > Instead, the current cpu checks whether an address space update > is required on each entry to the slow path. This certainly > catches all i/o. It easily works for the sequential case of > two i/o, the first of which changes the address space and the > second of which requires the new address space. > > I've done a tiny bit of performance testing between the two > solutions and it seems to be a wash. So now it's simply a > matter of cleanliness. Ho hum, this doesn't fix the x86_64 ovmf issue also quoted in #1866. r~