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=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 77B08C433B4 for ; Thu, 15 Apr 2021 18:01:53 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id ECFB96103D for ; Thu, 15 Apr 2021 18:01:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ECFB96103D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:35554 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lX6JL-0002WU-Kc for qemu-devel@archiver.kernel.org; Thu, 15 Apr 2021 14:01:51 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37506) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lX622-0008NW-UN for qemu-devel@nongnu.org; Thu, 15 Apr 2021 13:44:00 -0400 Received: from mail-pj1-x1030.google.com ([2607:f8b0:4864:20::1030]:33581) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lX61z-0004l5-2m for qemu-devel@nongnu.org; Thu, 15 Apr 2021 13:43:57 -0400 Received: by mail-pj1-x1030.google.com with SMTP id kb13-20020a17090ae7cdb02901503d67f0beso1751128pjb.0 for ; Thu, 15 Apr 2021 10:43:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=e2bQLxkyK6e3Kk2nLdEQ46l861Wy2SMGwWIy44j7jrM=; b=z2/wdTBYpoC+WSGFy4VmW5NIwwm+OoxMeEWwdKJsVH1Apjuhf97wq0wG8Qax5ARCYC IxsmPRjg+7UgamU/RhE6wT3zTfIcSTSfrl55Qn0tXZkILRMOBS/ZP/5zMfr5s44JiU3J IJp+l7zjkJNK5JfVsca/6pbx4+tKEfuwsbRV9TU6FPk0tV/Unv4CJ1rZif2QEdIYd5Mv 5STAWU0IeviwKigAJSJV/XfYFxEUm61maqAWJQpGA2YdCU+BLrXPxj1RSyRK4vi7JUd6 TkZ+urqxmgUhi8w+ePtU0LT4tq1smOhQPfhLXXvv6GVZSURf5DhlZ0k3RNxox40L+1Ey Kblg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=e2bQLxkyK6e3Kk2nLdEQ46l861Wy2SMGwWIy44j7jrM=; b=C+y56qorXPFskCq+SaOXyG/0dtWO6/fGdUsnfIA2JWGQwAeIoitGRxrkJgzNttVP2L fslvMorm8q9hSgzOmCqLJn15RLURUMdgmcMQ9w0W2kMxEoLBbHg88fTIkSGpt6IZwJ7x VPu6kuoA+NFYbuP/d64KGBKyTQQZBBheIAFV2dmNto/M2V6sW6Ao0lEJX5nz5eyeUqOM 8Pk+wnqr7yIiSth0ET8umG9z3Lfaw+2gQ1SCIik3qHdE6YfwHle5QNXAkOWlNPXatDga bO9BcTAwFev5EasvDIKSIO2W/0nX6AfVl+9tp4/eIVS4PVDs6s1AH509BvnftAmE45H7 iq3w== X-Gm-Message-State: AOAM531LsJt2JmSDNHN9Hxv7Up0UjuG7wf+Rv5fZxVKsn3MnKQZ/OnSG ZyaPi+cPPOzhXWfWtOEyyzCuig== X-Google-Smtp-Source: ABdhPJzMuDAntGnfpHfsDXdlW1Em3qWFh1XB1rWC/9tQ5cOqmt34pyjceau6uxMq7HuJ2/5r2JB5/A== X-Received: by 2002:a17:902:d645:b029:e8:ec90:d097 with SMTP id y5-20020a170902d645b02900e8ec90d097mr4927105plh.47.1618508632878; Thu, 15 Apr 2021 10:43:52 -0700 (PDT) Received: from [192.168.1.11] ([71.212.131.83]) by smtp.gmail.com with ESMTPSA id 205sm2721597pfc.201.2021.04.15.10.43.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 15 Apr 2021 10:43:52 -0700 (PDT) Subject: Re: [RFC PATCH] accel/tcg: avoid re-translating one-shot instructions To: =?UTF-8?Q?Alex_Benn=c3=a9e?= , qemu-devel@nongnu.org References: <20210415162454.22056-1-alex.bennee@linaro.org> From: Richard Henderson Message-ID: <24c3af00-b29b-fc63-9540-044c59128436@linaro.org> Date: Thu, 15 Apr 2021 10:43:50 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <20210415162454.22056-1-alex.bennee@linaro.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2607:f8b0:4864:20::1030; envelope-from=richard.henderson@linaro.org; helo=mail-pj1-x1030.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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=-0.001, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 4/15/21 9:24 AM, Alex Bennée wrote: > By definition a single instruction is capable of being an IO > instruction. This avoids a problem of triggering a cpu_io_recompile on > a non-recorded translation which then fails because it expects > tcg_tb_lookup() to succeed unconditionally. The normal use case > requires a TB to be able to resolve machine state. > > The other users of tcg_tb_lookup() are able to tolerate a missing TB > if the machine state has been resolved by other means - which in the > single-shot case is always true because machine state is synced at the > start of a block. > > Reported-by: Peter Maydell > Signed-off-by: Alex Bennée > --- > accel/tcg/translate-all.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Reviewed-by: Richard Henderson