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 22B68C369B2 for ; Mon, 14 Apr 2025 08:38:02 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1u4FJf-0002qf-KD; Mon, 14 Apr 2025 04:37:19 -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 1u4FJe-0002qW-6f for qemu-devel@nongnu.org; Mon, 14 Apr 2025 04:37:18 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1u4FJb-0001M7-Ma for qemu-devel@nongnu.org; Mon, 14 Apr 2025 04:37:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1744619829; h=from:from:reply-to: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=clXfms0hMcngIHUh9hMc6jy0AMhEWH3gKFMs3m4gZ1k=; b=QpdqBYszftI9m9zzuHux1Ohrm/kv8dIbTTbiHEH9kQIjcMAw1Wad9rD+99PNk6OXX1Iem9 t7gAIeVkq9gXZDhGXVlJU8fC1jGyJsLC3LLjOdgKjAPc3UjdMlUZxJXf70bwBDK5mphCTI Ocv4cRGv02isTwkgfzA9F4NLSo/LflI= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-554-B4kvsl9yPNq6erXrx7JZdw-1; Mon, 14 Apr 2025 04:37:04 -0400 X-MC-Unique: B4kvsl9yPNq6erXrx7JZdw-1 X-Mimecast-MFC-AGG-ID: B4kvsl9yPNq6erXrx7JZdw_1744619823 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 59D041956048; Mon, 14 Apr 2025 08:37:03 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.99]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7A22B1955BF6; Mon, 14 Apr 2025 08:37:01 +0000 (UTC) Date: Mon, 14 Apr 2025 09:36:57 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Richard Henderson Cc: qemu-devel@nongnu.org, stefanha@gmail.com, philmd@linaro.org Subject: Re: [PATCH for-10.0] docs: Document removal of 64-bit on 32-bit emulation Message-ID: References: <20250412164315.36161-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250412164315.36161-1-richard.henderson@linaro.org> User-Agent: Mutt/2.2.13 (2024-03-09) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=-1, RCVD_IN_MSPIKE_WL=-0.01, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= 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 09:43:15AM -0700, 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(+) > > diff --git a/docs/about/removed-features.rst b/docs/about/removed-features.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 hosts. > + > Guest Emulator ISAs > ------------------- Reviewed-by: Daniel P. Berrangé With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|