From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E470538BF61; Thu, 19 Mar 2026 16:39:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773938382; cv=none; b=q/Br8HjmborIltSyhLoancfJ3NhMhV6ePkEXswFxsS6ru0MXtob26LJBIkHVCN2QWkUDnMgQHTmXTCkRZCRrAcGEUsQoOEQSCir1EBmqKdjd9+IoFZ155ykIIEdvJ2uihFRNEiQqdC4m1moJOw7TvdQEbtY1K+tN1ovjUvbLa60= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773938382; c=relaxed/simple; bh=Y+Hv0DkWk/c+ewBI0ps5vOPQ63BNCB7+d21mTtAJtvo=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=dNkVrqjoCvIDbN/TAyMzvanvlwP9mV0uMYMMIk0HyHYLRP7eNrAnBlRgcDJxyUuOHA1jP8lbqjwzUWDq6jntF3dk1C+odb+9gUnQBTQV5zr/dqnxgj1OmrSpcIEfU5SVy5d7vYc7OX7WJEMrGacHGW1AxJW/G3UhSJVUXk8ZULQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=bmMuGENd; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="bmMuGENd" Received: from localhost (unknown [52.148.171.5]) by linux.microsoft.com (Postfix) with ESMTPSA id 744CF20B710C; Thu, 19 Mar 2026 09:39:33 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 744CF20B710C DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1773938375; bh=8r3Rrhjz62mzvDnQKQk9Pz54iwWA+pJBFG61+YWArBw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=bmMuGENdC7hPcV8u5wKM+LeF+mgtVIFSJy2h9p6W0i9+tl+Hp7PwExVnUfQO1xHwB Ouf5VcCqaSQUs5qKCHuxTDWMmMZ137/dgQcmFiu/HC6R4d58LdmNNYeQegg7/tAA4c QVfQmqGCCPaKOdhfIjpxs7czL0tSUxWhHGO5GW4k= Date: Thu, 19 Mar 2026 09:39:32 -0700 From: Jacob Pan To: David Matlack Cc: Alex Williamson , Adithya Jayachandran , Alexander Graf , Alex Mastro , Alistair Popple , Andrew Morton , Ankit Agrawal , Bjorn Helgaas , Chris Li , David Rientjes , Jason Gunthorpe , Jason Gunthorpe , Jonathan Corbet , Josh Hilke , Kevin Tian , kexec@lists.infradead.org, kvm@vger.kernel.org, Leon Romanovsky , Leon Romanovsky , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Lukas Wunner , =?UTF-8?Q?Mich?= =?UTF-8?Q?a=C5=82?= Winiarski , Mike Rapoport , Parav Pandit , Pasha Tatashin , Pranjal Shrivastava , Pratyush Yadav , Raghavendra Rao Ananta , Rodrigo Vivi , Saeed Mahameed , Samiullah Khawaja , Shuah Khan , Thomas =?UTF-8?Q?Hellstr=C3=B6m?= , Tomita Moeko , Vipin Sharma , Vivek Kasireddy , William Tu , Yi Liu , Zhu Yanjun Subject: Re: [PATCH v2 10/22] vfio/pci: Skip reset of preserved device after Live Update Message-ID: <20260319093932.000078c2@linux.microsoft.com> In-Reply-To: References: <20260129212510.967611-1-dmatlack@google.com> <20260129212510.967611-11-dmatlack@google.com> <20260226170030.5a938c74@shazbot.org> <20260227084658.3767d801@shazbot.org> <20260227105720.522ca97f@shazbot.org> <20260313083918.00005731@linux.microsoft.com> Organization: LSG X-Mailer: Claws Mail 3.21.0 (GTK+ 2.24.33; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi David, On Mon, 16 Mar 2026 11:11:20 -0700 David Matlack wrote: > On Fri, Mar 13, 2026 at 8:39=E2=80=AFAM Jacob Pan > wrote: > > On Thu, 12 Mar 2026 23:39:45 +0000 > > David Matlack wrote: =20 >=20 > > > +config VFIO_PCI_LIVEUPDATE > > > + bool "VFIO PCI support for Live Update (EXPERIMENTAL)" > > > + depends on LIVEUPDATE && VFIO_PCI > > > + help > > > + Support for preserving devices bound to vfio-pci across > > > a Live > > > + Update. The eventual goal is that preserved devices can > > > run > > > + uninterrupted during a Live Update, including DMA to > > > preserved > > > + memory buffers and P2P. However there are many steps > > > still needed to > > > + achieve this, including: > > > + > > > + - Preservation of iommufd files > > > + - Preservation of IOMMU driver state =20 > > In the interim, what do you think about moving forward with noiommu > > mode without preserving IOMMU driver state? =20 >=20 > I haven't gotten a chance to look at your noiommu patches yet, but I > do think noiommu will probably be a good way to develop the VFIO and > PCI support for Live Update without blocking on IOMMU driver support. >=20 > > I=E2=80=99ve tested your > > vfio_pci_liveupdate_kexec_test with the noiommu cdev, and it works > > as expected. =20 >=20 > Would you be able to send patches to add noiommu support to VFIO > selftests? That would be very helpful toward allowing us to develop > and test Live Update support with noiommu. It is included in the noiommu patchset; the only difference is that the VFIO cdev name is prefixed with noiommu, which is not strictly required and is done out of caution. /dev/vfio/ |-- devices | `-- noiommu-vfio0 https://lore.kernel.org/linux-iommu/20260312155637.376854-10-jacob.pan@linu= x.microsoft.com/