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 EA153CAC581 for ; Mon, 8 Sep 2025 14:42:52 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uvd2v-00066C-UO; Mon, 08 Sep 2025 10:40:42 -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 1uvd2m-00064r-Nf for qemu-devel@nongnu.org; Mon, 08 Sep 2025 10:40:33 -0400 Received: from mail-yw1-x112b.google.com ([2607:f8b0:4864:20::112b]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1uvd2d-0003x4-2d for qemu-devel@nongnu.org; Mon, 08 Sep 2025 10:40:32 -0400 Received: by mail-yw1-x112b.google.com with SMTP id 00721157ae682-71d60150590so34936737b3.0 for ; Mon, 08 Sep 2025 07:40:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1757342414; x=1757947214; darn=nongnu.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=ie34N3VBwqrFPbD6ojvoILKtO0smHKsr9OKY9vnHdMo=; b=YZtfefGjSLuStpyeKvUgnbfnh7IBXWPi1KHU52udca6UUBz3EAbUIRUHmoyiHu9jnM ZKx6k7jVdHLtkDhxu4lrB2scwIjb6tj2SPVTpXcDW3NdcG7bO/gk1iIwxszqVVjfHl+A OF+1Hq4GG9d+1qItvZnAUFER7eqXLIdPjtI7z9emijWZPGLzWTfdxVIRQ1kOtRAftmEF dJvwv8sy/G7OJoD2pmLg9eKfYKBerSRAb72cYGU6rdP2XwgbB8opDsXwyC13mSJZqLDB VG2LnN9+7tW8fT8U+bKI/aM4rnD06mbIPG4hDyrqxRCODKOxTjRhHC8iVUupGK1SfqSt XDQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757342414; x=1757947214; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=ie34N3VBwqrFPbD6ojvoILKtO0smHKsr9OKY9vnHdMo=; b=qef/qOj+81ljhmpGjmQNfHDMSN8SXufXb14pPMeQmbKE7ty+YSXUOvF8Q6lKoVSXXL lP+Fj2jIDvMjWCm4LEdF+R9cMx+W6+UGUdNGGuDBHp3SBbJAzbs20anMF2m2x8q+IPGR 3HbTpYee0tPdcRMiOTisH8EI3psMhZJucP7da1tqPq40oFNTO0a+8G7/a60kHPTeHHxj T0dQtNmDbVMXLiEzagneLWTmWoAyCziPgGbYegZcZYeIngfInhSGk6nmIZEtwUCLL+dv SPKK1IdeWaf4jVYuudxCKTqjHvQCT1wCd7MpekHVhW4jGlTD4guHzoOZO5UTOG9kUU+r dudw== X-Gm-Message-State: AOJu0Yzh8XL/Yf8RCArpos5lCPMiyseFS4IOjpEwn2j4K7uQdfQLph83 znjBcMb9Vo4XKtuv6zLeLCVhwU5byzwqhI8hNwuwSH2qVcyHJ7CV4ETiYGiNvDb/FOnJeB1Irvs +wNZKPG7xrJONLkQzXBleTqR0pi1VjKrZ3AJs53JfUQ== X-Gm-Gg: ASbGnctXuodpvZjeBdGATTKDyeIdb4/gCzjO5ndN8WZ4sKKDVIX8ksQWjhuO2r2zhV1 D3x7wlPqtau1B4DRULZ7Hln1Sy0xCPAGrvdawOtT1QVX+lGytaTKZqVM5Th0+9xS6N6FUXziI8p XhhdnjGZo8SW8NYAvgGCInQei2oYbUqEqxu8oub3+kW68UShv9nV8VFTT6cWSCDVBRyMT7Uh+GF VVvaXX3zBzUgI/rE+Y= X-Google-Smtp-Source: AGHT+IHhsjuNPyIzKMUeNxY5Mwm+esAXfiuk2vgektFdvaaf7I657hIB3fs6YRjKz2bWk7obYFxGkDBmm3Q6PDNxfWA= X-Received: by 2002:a05:690c:e1a:b0:721:1649:b070 with SMTP id 00721157ae682-727f5648a22mr68472707b3.44.1757342413782; Mon, 08 Sep 2025 07:40:13 -0700 (PDT) MIME-Version: 1.0 References: <20250830054128.448363-1-richard.henderson@linaro.org> <20250830054128.448363-22-richard.henderson@linaro.org> In-Reply-To: <20250830054128.448363-22-richard.henderson@linaro.org> From: Peter Maydell Date: Mon, 8 Sep 2025 15:40:01 +0100 X-Gm-Features: Ac12FXwwgwtZix-bigiwbIAlrULrTLg8Zc_nYKMGaTuwQu8P8XfMxdwGH5aikIE Message-ID: Subject: Re: [PATCH v4 21/84] target/arm: Do not migrate env->exception To: Richard Henderson Cc: qemu-devel@nongnu.org, qemu-arm@nongnu.org, =?UTF-8?Q?Philippe_Mathieu=2DDaud=C3=A9?= , Pierrick Bouvier Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2607:f8b0:4864:20::112b; envelope-from=peter.maydell@linaro.org; helo=mail-yw1-x112b.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, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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 Sat, 30 Aug 2025 at 16:56, Richard Henderson wrote: > > These are not architectural state, only placeholders > between identifying the exception and delivering it. Yes, but is it definitely guaranteed that QEMU will never do a migration or a record-and-replay record of the cpu state between identifying the exception and actually delivering it ? I note that we do migrate CPUState::exception_index (added in commit 6c3bff0ed8) which in theory would also be in this "non architectural state that we consume immediately" category: so presumably there is some situation where we might save out the state after we figure out that we need to raise an exception but before we call the target's do_interrupt hook. -- PMM