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 3BD05C369A2 for ; Mon, 14 Apr 2025 15:17:15 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1u4LYD-0002f9-Ae; Mon, 14 Apr 2025 11:16:45 -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 1u4LY0-0002dV-AX for qemu-devel@nongnu.org; Mon, 14 Apr 2025 11:16:39 -0400 Received: from mail-ed1-x535.google.com ([2a00:1450:4864:20::535]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1u4LXy-0000y6-3d for qemu-devel@nongnu.org; Mon, 14 Apr 2025 11:16:31 -0400 Received: by mail-ed1-x535.google.com with SMTP id 4fb4d7f45d1cf-5e60cfef9cfso7446587a12.2 for ; Mon, 14 Apr 2025 08:16:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1744643787; x=1745248587; darn=nongnu.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=VR6hr5Q8tZ9P51V6WO9fFP4WiUhTFfS9tVwAoP/OGN0=; b=fgn2/89/dLwmymixysga9W/BuVWLLk7CUWBGtL0MK0XTwmfevirRsR3AR5iDQIrsb0 99JKhLma5wwWZY4EBwLtvSAfYyZ+FosStmVnJLj3oWKeTDvfqInF4I7CUsNgwJob5EuF 0OFtl4dn2sqdWYjJ02UMpGzFG22nwrIaKasz97aIboxuSKegKaWLN3R2DXP9RISPz1by TuvWPCduqh73rZHdhzg/dk3tzVk2hAtygZYxbmdCfZcWzra5fsbKNPG8g/atmCYmkdaP erp6rjGpIh7BFzG5vBEr3WmUA3+KKhhi9NSui9wz1Y4XRRJ/y4k2oex2AwlV4C1sNx01 qZ0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1744643787; x=1745248587; h=content-transfer-encoding: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=VR6hr5Q8tZ9P51V6WO9fFP4WiUhTFfS9tVwAoP/OGN0=; b=GiFMaDKTf0AcPKQGk2ofWJgM/N3YbvLZGMRsso8qXbz27Xpah4MWoJSLhEOCfbM30E uZ0cHdcrQAHG/GykH2gkXZoT+9RZyTgHX71rXSRatvDQNiBLuSN/vKvUUF2BZ8RYInlL W+0HPNqarD+kX3bOKiSMLcNr/WFAfns0gVL+dmrWVLmxkkVgYC/haHb5/sfV8dF9BCKw nQveDjVDTD5vN1fXUbAGXmb+r8WRZBFrnkM36rQ26Ni+jXgEthUg2X9n40tLHsQXWelp ylY2eMnNAqXapvIq5/ss5kq4cd4wZaQ+becyqgNtbsRt/8zN0M3jCKKnvb5aYOpvskR3 0FXg== X-Gm-Message-State: AOJu0YwOqtBOiuKN1hOuJ565mJMjUmhs5T20f7MEGPfG91UugCIK3jQy oBQFp/tYXo2Md2ee6R3N8hueFo03mStiR+rysG9jAcRUSO2/eLcwh/tsbP4pu51YftCevj8ZY35 nqYHKJlmQ2wRLxQUcFzD0Na8iFEc= X-Gm-Gg: ASbGncs5oGML5epWMvy2ko+hppQPUbg+gAN/uLjwJs92qPFI1ldvS0kzbkwUv65MknC 2f2NJ5u+f/ozqwBWKhEFD2ZKGGNKp7zFhF58KnqynjK2S9VcphyRZg5QE6JhAuFZSps9d0ypaD+ yVw9gylJ4K+/GLUWhuPrzc X-Google-Smtp-Source: AGHT+IGXuexUWm/g8sHuowdXAw8sePqZQfDRxBBYmLnsgjhT/1klF2L8UO412IRdWKBJEY3DCk7toesy4LPunC4x7u0= X-Received: by 2002:a05:6402:51ce:b0:5e7:5b30:3c4f with SMTP id 4fb4d7f45d1cf-5f36f77bab2mr10212484a12.14.1744643786885; Mon, 14 Apr 2025 08:16:26 -0700 (PDT) MIME-Version: 1.0 References: <20250412164315.36161-1-richard.henderson@linaro.org> In-Reply-To: <20250412164315.36161-1-richard.henderson@linaro.org> From: Stefan Hajnoczi Date: Mon, 14 Apr 2025 11:16:15 -0400 X-Gm-Features: ATxdqUGzX8yLcGiv70MfS1yAH2SdHDwGOksYqSx3_bpaeLN2WsQiB85fJwspuo0 Message-ID: Subject: Re: [PATCH for-10.0] docs: Document removal of 64-bit on 32-bit emulation To: Richard Henderson Cc: qemu-devel@nongnu.org, berrange@redhat.com, philmd@linaro.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2a00:1450:4864:20::535; envelope-from=stefanha@gmail.com; helo=mail-ed1-x535.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, FREEMAIL_FROM=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: 2.1.29 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, Apr 12, 2025 at 12:43=E2=80=AFPM Richard Henderson wrote: > > With acce728cbc6c we disallowed configuring 64-bit guests on > 32-bit hosts, but forgot to document that in removed-features. > > Signed-off-by: Richard Henderson > --- > docs/about/removed-features.rst | 9 +++++++++ > 1 file changed, 9 insertions(+) Merged for 10.0 via Michael Tokarev's trivial patches pull request. Stefan > > diff --git a/docs/about/removed-features.rst b/docs/about/removed-feature= s.rst > index 2527a91795..790a5e481c 100644 > --- a/docs/about/removed-features.rst > +++ b/docs/about/removed-features.rst > @@ -858,6 +858,15 @@ QEMU. Since all recent x86 hardware from the past >= 10 years is > capable of the 64-bit x86 extensions, a corresponding 64-bit OS should > be used instead. > > +32-bit hosts for 64-bit guests (removed in 10.0) > +'''''''''''''''''''''''''''''''''''''''''''''''' > + > +In general, 32-bit hosts cannot support the memory space or atomicity > +requirements of 64-bit guests. Prior to 10.0, QEMU attempted to > +work around the atomicity issues in system mode by running all vCPUs > +in a single thread context; in user mode atomicity was simply broken. > +From 10.0, QEMU has disabled configuration of 64-bit guests on 32-bit ho= sts. > + > Guest Emulator ISAs > ------------------- > > -- > 2.43.0 >