[{"id":3669625,"web_url":"http://patchwork.ozlabs.org/comment/3669625/","msgid":"<87a4vuhnxy.fsf@pond.sub.org>","list_archive_url":null,"date":"2026-03-26T10:42:17","subject":"Re: [PATCH 1/9] hw/mem: Add tag support to generic host memory\n backends","submitter":{"id":2645,"url":"http://patchwork.ozlabs.org/api/people/2645/","name":"Markus Armbruster","email":"armbru@redhat.com"},"content":"Alireza Sanaee <alireza.sanaee@huawei.com> writes:\n\n> Add a string tag property to HostMemoryBackend so that backends can be\n> identified by a user-assigned name at runtime. Expose the property through\n> QOM and add a host_memory_backend_find_by_tag() helper that walks the\n> object tree to locate a backend by its tag.\n\nWhy can't you use the QOM ID?\n\n$ qemu-system-x86_64 -S -display none -monitor stdio -object memory-backend-ram,id=fred,size=1M\nQEMU 10.2.90 monitor - type 'help' for more information\n(qemu) info qom-tree /objects/fred\n/fred (memory-backend-ram)\n  /fred[0] (memory-region)","headers":{"Return-Path":"<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=Tb5YYGVw;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)"],"Received":["from lists.gnu.org (lists.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fhL366k2Xz1y1G\n\tfor <incoming@patchwork.ozlabs.org>; Thu, 26 Mar 2026 21:43:13 +1100 (AEDT)","from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from <qemu-devel-bounces@nongnu.org>)\n\tid 1w5iAd-000695-KJ; Thu, 26 Mar 2026 06:42:35 -0400","from eggs.gnu.org ([2001:470:142:3::10])\n by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from <armbru@redhat.com>) id 1w5iAX-00068T-Nb\n for qemu-devel@nongnu.org; Thu, 26 Mar 2026 06:42:29 -0400","from us-smtp-delivery-124.mimecast.com ([170.10.133.124])\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from <armbru@redhat.com>) id 1w5iAW-0006ww-7E\n for qemu-devel@nongnu.org; Thu, 26 Mar 2026 06:42:29 -0400","from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com\n (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by\n relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3,\n cipher=TLS_AES_256_GCM_SHA384) id us-mta-14-7NkrLcZKNYCwbta6h5sLGQ-1; Thu,\n 26 Mar 2026 06:42:23 -0400","from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com\n (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17])\n (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest\n SHA256)\n (No client certificate requested)\n by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS\n id 20E5619560B1; Thu, 26 Mar 2026 10:42:21 +0000 (UTC)","from blackfin.pond.sub.org (unknown [10.45.242.6])\n by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with\n ESMTPS\n id CB6221955D84; Thu, 26 Mar 2026 10:42:19 +0000 (UTC)","by blackfin.pond.sub.org (Postfix, from userid 1000)\n id 622E321E6937; Thu, 26 Mar 2026 11:42:17 +0100 (CET)"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;\n s=mimecast20190719; t=1774521747;\n h=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n to:to:cc:cc:mime-version:mime-version:content-type:content-type:\n in-reply-to:in-reply-to:references:references;\n bh=uRiVM/hQz0BvpG69+7beiImyjSsPHNvKncV4RQM/tmk=;\n b=Tb5YYGVwjnw7C1bAjM/3GcYIGrXD5f9l8VZWRjOY+sjNVHSrCUW9UzDUTkKeB9vei13Msn\n ycn7xEhLPRgYjIZZYTbRJq8z/4Jhn/tHTuuTh6OImLAQ8aZ1ONjk3Bba/J/TITgDCNGAz7\n VV67pTZcNy5E1rcw8iJOpQmukJFzBDg=","X-MC-Unique":"7NkrLcZKNYCwbta6h5sLGQ-1","X-Mimecast-MFC-AGG-ID":"7NkrLcZKNYCwbta6h5sLGQ_1774521742","From":"Markus Armbruster <armbru@redhat.com>","To":"Alireza Sanaee <alireza.sanaee@huawei.com>","Cc":"<qemu-devel@nongnu.org>,  <anisa.su@samsung.com>,\n <berrange@redhat.com>,  <eblake@redhat.com>,\n <jonathan.cameron@huawei.com>,  <linux-cxl@vger.kernel.org>,\n <linuxarm@huawei.com>,  <lizhijian@fujitsu.com>,  <mst@redhat.com>,\n <pbonzini@redhat.com>,  <gourry@gourry.net>,  <nifan.cxl@gmail.com>,\n <me@linux.beauty>","Subject":"Re: [PATCH 1/9] hw/mem: Add tag support to generic host memory\n backends","In-Reply-To":"<20260325184259.366-2-alireza.sanaee@huawei.com> (Alireza\n Sanaee's message of \"Wed, 25 Mar 2026 18:42:49 +0000\")","References":"<20260325184259.366-1-alireza.sanaee@huawei.com>\n <20260325184259.366-2-alireza.sanaee@huawei.com>","Date":"Thu, 26 Mar 2026 11:42:17 +0100","Message-ID":"<87a4vuhnxy.fsf@pond.sub.org>","User-Agent":"Gnus/5.13 (Gnus v5.13)","MIME-Version":"1.0","Content-Type":"text/plain","X-Scanned-By":"MIMEDefang 3.0 on 10.30.177.17","Received-SPF":"pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com;\n helo=us-smtp-delivery-124.mimecast.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, DKIMWL_WL_HIGH=-0.001,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=0.001,\n RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001,\n SPF_HELO_PASS=-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":"qemu development <qemu-devel.nongnu.org>","List-Unsubscribe":"<https://lists.nongnu.org/mailman/options/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>","List-Archive":"<https://lists.nongnu.org/archive/html/qemu-devel>","List-Post":"<mailto:qemu-devel@nongnu.org>","List-Help":"<mailto:qemu-devel-request@nongnu.org?subject=help>","List-Subscribe":"<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=subscribe>","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"}},{"id":3669654,"web_url":"http://patchwork.ozlabs.org/comment/3669654/","msgid":"<20260326112921.000028e6.alireza.sanaee@huawei.com>","list_archive_url":null,"date":"2026-03-26T11:29:21","subject":"Re: [PATCH 1/9] hw/mem: Add tag support to generic host memory\n backends","submitter":{"id":90159,"url":"http://patchwork.ozlabs.org/api/people/90159/","name":"Alireza Sanaee","email":"alireza.sanaee@huawei.com"},"content":"On Thu, 26 Mar 2026 11:42:17 +0100\nMarkus Armbruster <armbru@redhat.com> wrote:\n\nHi Markus,\n\n> Alireza Sanaee <alireza.sanaee@huawei.com> writes:\n> \n> > Add a string tag property to HostMemoryBackend so that backends can be\n> > identified by a user-assigned name at runtime. Expose the property through\n> > QOM and add a host_memory_backend_find_by_tag() helper that walks the\n> > object tree to locate a backend by its tag.  \n> \n> Why can't you use the QOM ID?\n> \n> $ qemu-system-x86_64 -S -display none -monitor stdio -object memory-backend-ram,id=fred,size=1M\n> QEMU 10.2.90 monitor - type 'help' for more information\n> (qemu) info qom-tree /objects/fred\n> /fred (memory-backend-ram)\n>   /fred[0] (memory-region)\n> \n>  \n\nFair question. The ID would have been a solution if it had accepted GUIDs. CXL spec \nrequires GUIDs for extents as identification, hence new tag property.\n\nalireza@blue-ocean:~/Downloads$ qemu-system-x86_64 -s -display none -monitor std\nio -object memory-backend-ram,id=02bb2436-e87d-4aa1-b2be-aaffdd76bb79,size=1M\nqemu-system-x86_64: -object memory-backend-ram,id=02bb2436-e87d-4aa1-b2be-aaffdd\n76bb79,size=1M: Parameter 'id' expects an identifier\nIdentifiers consist of letters, digits, '-', '.', '_', starting with a letter.\n\nThanks,\nAli","headers":{"Return-Path":"<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":"legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)","Received":["from lists.gnu.org (lists.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fhM5D2NCXz1y1x\n\tfor <incoming@patchwork.ozlabs.org>; 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Thu, 26 Mar\n 2026 11:29:27 +0000"],"Date":"Thu, 26 Mar 2026 11:29:21 +0000","To":"Markus Armbruster <armbru@redhat.com>","CC":"<qemu-devel@nongnu.org>, <anisa.su@samsung.com>, <berrange@redhat.com>,\n <eblake@redhat.com>, <jonathan.cameron@huawei.com>,\n <linux-cxl@vger.kernel.org>, <linuxarm@huawei.com>, <lizhijian@fujitsu.com>,\n <mst@redhat.com>, <pbonzini@redhat.com>, <gourry@gourry.net>,\n <nifan.cxl@gmail.com>, <me@linux.beauty>","Subject":"Re: [PATCH 1/9] hw/mem: Add tag support to generic host memory\n backends","Message-ID":"<20260326112921.000028e6.alireza.sanaee@huawei.com>","In-Reply-To":"<87a4vuhnxy.fsf@pond.sub.org>","References":"<20260325184259.366-1-alireza.sanaee@huawei.com>\n <20260325184259.366-2-alireza.sanaee@huawei.com>\n <87a4vuhnxy.fsf@pond.sub.org>","Organization":"Huawei","X-Mailer":"Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32)","MIME-Version":"1.0","Content-Type":"text/plain; charset=\"US-ASCII\"","Content-Transfer-Encoding":"7bit","X-Originating-IP":"[10.203.177.99]","X-ClientProxiedBy":"lhrpeml100010.china.huawei.com (7.191.174.197) To\n dubpeml500005.china.huawei.com (7.214.145.207)","Received-SPF":"pass client-ip=185.176.79.56;\n envelope-from=alireza.sanaee@huawei.com; helo=frasgout.his.huawei.com","X-Spam_score_int":"-41","X-Spam_score":"-4.2","X-Spam_bar":"----","X-Spam_report":"(-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3,\n RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001,\n RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001,\n 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":"qemu development <qemu-devel.nongnu.org>","List-Unsubscribe":"<https://lists.nongnu.org/mailman/options/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>","List-Archive":"<https://lists.nongnu.org/archive/html/qemu-devel>","List-Post":"<mailto:qemu-devel@nongnu.org>","List-Help":"<mailto:qemu-devel-request@nongnu.org?subject=help>","List-Subscribe":"<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=subscribe>","Reply-to":"Alireza Sanaee <alireza.sanaee@huawei.com>","From":"Alireza Sanaee via qemu development <qemu-devel@nongnu.org>","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"}},{"id":3669712,"web_url":"http://patchwork.ozlabs.org/comment/3669712/","msgid":"<87bjgag2y5.fsf@pond.sub.org>","list_archive_url":null,"date":"2026-03-26T13:01:06","subject":"Re: [PATCH 1/9] hw/mem: Add tag support to generic host memory\n backends","submitter":{"id":2645,"url":"http://patchwork.ozlabs.org/api/people/2645/","name":"Markus Armbruster","email":"armbru@redhat.com"},"content":"Alireza Sanaee <alireza.sanaee@huawei.com> writes:\n\n> On Thu, 26 Mar 2026 11:42:17 +0100\n> Markus Armbruster <armbru@redhat.com> wrote:\n>\n> Hi Markus,\n>\n>> Alireza Sanaee <alireza.sanaee@huawei.com> writes:\n>> \n>> > Add a string tag property to HostMemoryBackend so that backends can be\n>> > identified by a user-assigned name at runtime. Expose the property through\n>> > QOM and add a host_memory_backend_find_by_tag() helper that walks the\n>> > object tree to locate a backend by its tag.  \n>> \n>> Why can't you use the QOM ID?\n>> \n>> $ qemu-system-x86_64 -S -display none -monitor stdio -object memory-backend-ram,id=fred,size=1M\n>> QEMU 10.2.90 monitor - type 'help' for more information\n>> (qemu) info qom-tree /objects/fred\n>> /fred (memory-backend-ram)\n>>   /fred[0] (memory-region)\n>> \n>>  \n>\n> Fair question. The ID would have been a solution if it had accepted GUIDs. CXL spec \n> requires GUIDs for extents as identification, hence new tag property.\n\nYour commit message should state that this needs to be a GUID and why.\n\n> alireza@blue-ocean:~/Downloads$ qemu-system-x86_64 -s -display none -monitor std\n> io -object memory-backend-ram,id=02bb2436-e87d-4aa1-b2be-aaffdd76bb79,size=1M\n> qemu-system-x86_64: -object memory-backend-ram,id=02bb2436-e87d-4aa1-b2be-aaffdd\n> 76bb79,size=1M: Parameter 'id' expects an identifier\n> Identifiers consist of letters, digits, '-', '.', '_', starting with a letter.\n>\n> Thanks,\n> Ali","headers":{"Return-Path":"<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=GY+2M+Rp;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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Thu, 26 Mar 2026 14:01:07 +0100 (CET)"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;\n s=mimecast20190719; t=1774530082;\n h=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n to:to:cc:cc:mime-version:mime-version:content-type:content-type:\n in-reply-to:in-reply-to:references:references;\n bh=dgqnh8YCVC64TnA3VJFCquY3LHbWRG2/wHmvHeqgzDw=;\n b=GY+2M+RptLCcfW6nYQGPNPs6J5WUa0uNqKDh+50rdiJW4HX2kw6Y6wr940JLC9bLVo/+jK\n U6p3TjjguC1NAIzoIya+p09fEwYdjTPECe34bshRqIDb/RS+7+/IEdJ6ILuELznwpCqw1O\n eintz1vESrTBSIx5xrRSZx6rLf3JOT4=","X-MC-Unique":"dkj09fOLMO2CHio9kGdSLw-1","X-Mimecast-MFC-AGG-ID":"dkj09fOLMO2CHio9kGdSLw_1774530071","From":"Markus Armbruster <armbru@redhat.com>","To":"Alireza Sanaee <alireza.sanaee@huawei.com>","Cc":"<qemu-devel@nongnu.org>,  <anisa.su@samsung.com>,\n <berrange@redhat.com>,  <eblake@redhat.com>,\n <jonathan.cameron@huawei.com>,  <linux-cxl@vger.kernel.org>,\n <linuxarm@huawei.com>,  <lizhijian@fujitsu.com>,  <mst@redhat.com>,\n <pbonzini@redhat.com>,  <gourry@gourry.net>,  <nifan.cxl@gmail.com>,\n <me@linux.beauty>","Subject":"Re: [PATCH 1/9] hw/mem: Add tag support to generic host memory\n backends","In-Reply-To":"<20260326112921.000028e6.alireza.sanaee@huawei.com> (Alireza\n Sanaee's message of \"Thu, 26 Mar 2026 11:29:21 +0000\")","References":"<20260325184259.366-1-alireza.sanaee@huawei.com>\n <20260325184259.366-2-alireza.sanaee@huawei.com>\n <87a4vuhnxy.fsf@pond.sub.org>\n <20260326112921.000028e6.alireza.sanaee@huawei.com>","Date":"Thu, 26 Mar 2026 14:01:06 +0100","Message-ID":"<87bjgag2y5.fsf@pond.sub.org>","User-Agent":"Gnus/5.13 (Gnus v5.13)","MIME-Version":"1.0","Content-Type":"text/plain","X-Scanned-By":"MIMEDefang 3.4.1 on 10.30.177.4","Received-SPF":"pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com;\n helo=us-smtp-delivery-124.mimecast.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, DKIMWL_WL_HIGH=-0.001,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=0.001,\n RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001,\n SPF_HELO_PASS=-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":"qemu development <qemu-devel.nongnu.org>","List-Unsubscribe":"<https://lists.nongnu.org/mailman/options/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>","List-Archive":"<https://lists.nongnu.org/archive/html/qemu-devel>","List-Post":"<mailto:qemu-devel@nongnu.org>","List-Help":"<mailto:qemu-devel-request@nongnu.org?subject=help>","List-Subscribe":"<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=subscribe>","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"}},{"id":3669715,"web_url":"http://patchwork.ozlabs.org/comment/3669715/","msgid":"<20260326130409.0000405b.alireza.sanaee@huawei.com>","list_archive_url":null,"date":"2026-03-26T13:04:09","subject":"Re: [PATCH 1/9] hw/mem: Add tag support to generic host memory\n backends","submitter":{"id":90159,"url":"http://patchwork.ozlabs.org/api/people/90159/","name":"Alireza Sanaee","email":"alireza.sanaee@huawei.com"},"content":"On Thu, 26 Mar 2026 14:01:06 +0100\nMarkus Armbruster <armbru@redhat.com> wrote:\n\nHi Markus,\n\nSure, absolutely.\n> Alireza Sanaee <alireza.sanaee@huawei.com> writes:\n> \n> > On Thu, 26 Mar 2026 11:42:17 +0100\n> > Markus Armbruster <armbru@redhat.com> wrote:\n> >\n> > Hi Markus,\n> >  \n> >> Alireza Sanaee <alireza.sanaee@huawei.com> writes:\n> >>   \n> >> > Add a string tag property to HostMemoryBackend so that backends can be\n> >> > identified by a user-assigned name at runtime. Expose the property through\n> >> > QOM and add a host_memory_backend_find_by_tag() helper that walks the\n> >> > object tree to locate a backend by its tag.    \n> >> \n> >> Why can't you use the QOM ID?\n> >> \n> >> $ qemu-system-x86_64 -S -display none -monitor stdio -object memory-backend-ram,id=fred,size=1M\n> >> QEMU 10.2.90 monitor - type 'help' for more information\n> >> (qemu) info qom-tree /objects/fred\n> >> /fred (memory-backend-ram)\n> >>   /fred[0] (memory-region)\n> >> \n> >>    \n> >\n> > Fair question. The ID would have been a solution if it had accepted GUIDs. CXL spec \n> > requires GUIDs for extents as identification, hence new tag property.  \n> \n> Your commit message should state that this needs to be a GUID and why.\n> \n> > alireza@blue-ocean:~/Downloads$ qemu-system-x86_64 -s -display none -monitor std\n> > io -object memory-backend-ram,id=02bb2436-e87d-4aa1-b2be-aaffdd76bb79,size=1M\n> > qemu-system-x86_64: -object memory-backend-ram,id=02bb2436-e87d-4aa1-b2be-aaffdd\n> > 76bb79,size=1M: Parameter 'id' expects an identifier\n> > Identifiers consist of letters, digits, '-', '.', '_', starting with a letter.\n> >\n> > Thanks,\n> > Ali  \n> \n>","headers":{"Return-Path":"<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":"legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)","Received":["from lists.gnu.org (lists.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fhPBK4Y1Dz1y1x\n\tfor <incoming@patchwork.ozlabs.org>; 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Thu, 26 Mar\n 2026 13:04:13 +0000"],"Date":"Thu, 26 Mar 2026 13:04:09 +0000","To":"Markus Armbruster <armbru@redhat.com>","CC":"<qemu-devel@nongnu.org>, <anisa.su@samsung.com>, <berrange@redhat.com>,\n <eblake@redhat.com>, <jonathan.cameron@huawei.com>,\n <linux-cxl@vger.kernel.org>, <linuxarm@huawei.com>, <lizhijian@fujitsu.com>,\n <mst@redhat.com>, <pbonzini@redhat.com>, <gourry@gourry.net>,\n <nifan.cxl@gmail.com>, <me@linux.beauty>","Subject":"Re: [PATCH 1/9] hw/mem: Add tag support to generic host memory\n backends","Message-ID":"<20260326130409.0000405b.alireza.sanaee@huawei.com>","In-Reply-To":"<87bjgag2y5.fsf@pond.sub.org>","References":"<20260325184259.366-1-alireza.sanaee@huawei.com>\n <20260325184259.366-2-alireza.sanaee@huawei.com>\n <87a4vuhnxy.fsf@pond.sub.org>\n <20260326112921.000028e6.alireza.sanaee@huawei.com>\n <87bjgag2y5.fsf@pond.sub.org>","Organization":"Huawei","X-Mailer":"Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32)","MIME-Version":"1.0","Content-Type":"text/plain; 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