From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 97318606A324 for ; Wed, 11 Nov 2026 12:51:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=Bp8W5Obs Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1xR7nU-0004Tp-09; Wed, 11 Nov 2026 07:51:28 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1xR7nQ-0004TY-OO for qemu-devel@nongnu.org; Wed, 11 Nov 2026 07:51:24 -0500 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 1xR7nN-0004y2-V1 for qemu-devel@nongnu.org; Wed, 11 Nov 2026 07:51:23 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1794401480; 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=QqZywVtdKpDoDct9QbSTfhQtfQ8nn61ZfJnTV1dDQlA=; b=Bp8W5ObsuT884EczzItvkhYzurPiU3t1J4wavq6oNo2el//DLFgs0Twe0adVhqLNFDFGdq B4NbWpkQevJ+d9z0jq4yc8TYE+QL4RibX9D90t5lMQN6blB+bshHPo0+5x6bPzqLuoBR5I 3sqL20OGDAD6NX8qDx5cbHm6eheqC6s= Received: from mx-prod-mc-05.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-608-CWKx5wQRN9qewhywQiQ-MA-1; Wed, 11 Nov 2026 07:51:17 -0500 X-MC-Unique: CWKx5wQRN9qewhywQiQ-MA-1 X-Mimecast-MFC-AGG-ID: CWKx5wQRN9qewhywQiQ-MA_1794401476 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id F419519560B7; Wed, 11 Nov 2026 12:51:15 +0000 (UTC) Received: from redhat.com (headnet04.pony-001.prod.iad2.dc.redhat.com [10.2.32.116]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8528C30001A2; Wed, 11 Nov 2026 12:51:14 +0000 (UTC) Date: Wed, 11 Nov 2026 12:51:11 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Markus Armbruster Cc: qemu-devel@nongnu.org, david@kernel.org, imammedo@redhat.com, peter.maydell@linaro.org Subject: Re: [PATCH 3/7] backends/hostmem: Improve error reporting when method alloc() fails Message-ID: References: <20261111122342.634370-1-armbru@redhat.com> <20261111122342.634370-4-armbru@redhat.com> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20261111122342.634370-4-armbru@redhat.com> User-Agent: Mutt/2.4.3 (2026-10-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 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: 5 X-Spam_score: 0.5 X-Spam_bar: / X-Spam_report: (0.5 / 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_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org X-Spam-Status: No, score=-17.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Wed, Nov 11, 2026 at 01:23:38PM +0100, Markus Armbruster wrote: > When HostMemoryBackend method alloc() fails, the error report isn't > always clear. E.g. "-object memory-backend-shm,id=mem0,size=1E" fails > for me like this: > > qemu-system-x86_64: unable to map backing store for guest RAM: Cannot allocate memory > > Leaves users guessing which part of the (often lengthy) command line > needs fixing. > > Let's prepend a bit of context: > > qemu-system-x86_64: can't create memory-backend-shm: unable to map backing store for guest RAM: Cannot allocate memory > > This makes an error message in shm_backend_memory_alloc() partly > redundant: > > qemu-system-x86_64: can't create memory-backend-shm: can't create shm backend with `share=off` > > Change it to > > qemu-system-x86_64: can't create memory-backend-shm: backend requires 'share=on' > > Signed-off-by: Markus Armbruster > --- > backends/hostmem-shm.c | 2 +- > backends/hostmem.c | 3 +++ > 2 files changed, 4 insertions(+), 1 deletion(-) Reviewed-by: Daniel P. Berrangé With regards, Daniel -- |: https://berrange.com ~~ https://hachyderm.io/@berrange :| |: https://libvirt.org ~~ https://entangle-photo.org :| |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :|