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 lists1p.gnu.org (lists1p.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 94E68F9D0CD for ; Tue, 14 Apr 2026 12:43:18 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wCd6A-0008Am-Ef; Tue, 14 Apr 2026 08:42:34 -0400 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 1wCd69-0008AW-Nd for qemu-devel@nongnu.org; Tue, 14 Apr 2026 08:42:33 -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 1wCd68-00030e-Bg for qemu-devel@nongnu.org; Tue, 14 Apr 2026 08:42:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1776170551; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=64C2YsslG2c/XZX4KWE47mEgBaDHV+zeHySbSFO5g8c=; b=XPJIT1NPcCXTnEcWWEO1gWvvJilcoKrhcpd9dWQi9LYXjNLU6PzkXFdv+a1rLUik/rInkW 0r/KLDN0r0+AAo8Dait11ikEDdFSftR5QiTQ7FLOkEvKkuKNDAdRKKca2Ir04gRWcapFD+ HUzdOUqeLxDVOqfImN4sL9Hex8BI6q0= Received: from mx-prod-mc-01.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-18-KqmYqaqZPyS1xAMPi1Rt1A-1; Tue, 14 Apr 2026 08:42:26 -0400 X-MC-Unique: KqmYqaqZPyS1xAMPi1Rt1A-1 X-Mimecast-MFC-AGG-ID: KqmYqaqZPyS1xAMPi1Rt1A_1776170545 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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id CFD1519560B8; Tue, 14 Apr 2026 12:42:24 +0000 (UTC) Received: from localhost (unknown [10.44.50.237]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id C0C4B3000C1F; Tue, 14 Apr 2026 12:42:23 +0000 (UTC) Date: Tue, 14 Apr 2026 08:42:21 -0400 From: Stefan Hajnoczi To: Klaus Jensen Cc: mr-083 , qemu-devel@nongnu.org, qemu-block@nongnu.org, kbusch@kernel.org, mr-083 , John Meneghini Subject: Re: [PATCH 0/2] NVMe namespace hotplug and drive reconnection support Message-ID: <20260414124221.GB111076@fedora> References: <20260409060155.94704-1-matthieu@min.io> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="xAu5N7wFZwOlRHtN" Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 7 X-Spam_score: 0.7 X-Spam_bar: / X-Spam_report: (0.7 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.54, 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_H2=0.001, RCVD_IN_SBL_CSS=3.335, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, 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-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 --xAu5N7wFZwOlRHtN Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Apr 13, 2026 at 07:17:37PM +0200, Klaus Jensen wrote: > On Apr 9 08:01, mr-083 wrote: > > This series adds two features that together enable transparent NVMe disk > > hot-swap simulation in QEMU, matching the behavior of physical NVMe > > drives being pulled and reinserted in the same PCIe slot. > >=20 >=20 > I don't understand this. From an NVMe perspective you can't hotplug a > namespace. You can hotplug a PCIe-based NVM Subsystem. Hi Klaus, It would be great if someone with more NVMe experience than myself can find a definite answer, but I think the Namespace List can change asynchronously even on a NVMe PCIe controller as long as it supports Namespace Management commands. There are instances in the NVMe Express Base Specification 2.0b like: - 8.3.1 Capacity Management Overview "a Namespace Attribute Changed event is generated for hosts other than the host which issued the Capacity Management command" - 8.11 Namespace Management "If Namespace Attribute Notices are enabled, any controller(s) not processing the Namespace Management command that was attached to the namespace reports a Namespace Attribute Changed asynchronous event to the host." I imagine this functionality would be useful in storage offload cards (IPUs/DPUs) that present as NVMe PCIe controllers instead of as NVMe-over-Fabrics. This makes sense when the host is not supposed to manage the storage itself. When the card's control plane configures a new volume, the NVMe Namespace List changes and the host is notified. Linux and Windows NVMe PCI drivers support this according to the testing that Matthieu and I have done. Thanks, Stefan --xAu5N7wFZwOlRHtN Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmneNiwACgkQnKSrs4Gr c8igTQgApBp5b1M7ekqyYRSyxicOF16k7484FS7e7aKbMhGKgW4kY81y8f9FKQdV cSKAH3OR5E+uQSSN5mr0I0OZi7fahQh6TEq+v5kq/RuomEJwAcMQERX+qoFeZ81w uZ7h2zqICUML2vieHugfb8Trk6GEwlQPL3U1Lu07ML7xOMduYV/Qj1jC/Zy1NDiA KUfYepPe3tPMFLPmztmOZeDfSOg3VI2joFavdyZ655CAUR32PCfI47gcM1b0e9lk PQXcn07vW6fQ68q5r11F+G+37gDAbY4X3Kw7k+mMZhBF+ynRNyfla4ygpPnCpAXu LvawpetldV5wyrHOdIKf7kvXG+cj7g== =gTsi -----END PGP SIGNATURE----- --xAu5N7wFZwOlRHtN--