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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) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 061EE1C0004 X-Rspamd-Server: rspam07 X-Stat-Signature: qxob81izkrg8yi1dsoagns76zbtwx51g X-Rspam-User: X-HE-Tag: 1773938375-570769 X-HE-Meta: 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 65CtzQe1 5BrDLcgjY6qXn5LK8tAuUwb0xZ38a/VQGppEs8kDn+aPzlvCEks08fb9CMN/olP3HMdf/VaFPZ9kKwwdqsvSEdued5xAwxbrVmRWpwIDd6J7AAbaEhyqbZmaGs88Rsh0NhzWtYQ6N5n/zTmdSDpa2ctnYhsWXGeZmBQ7sVTMWAk+u5Hr1c2rfo6CkZPCoW9tlXBxLECQv5p0Mn9PBL3Kqz86T4dinLoIT40ItJxck6kYkVPFHa+kvwp85Um2S9beGdxXwHzEunTcMlPv8UiKsGSYnuHc03tnouzb/CWTQlSywlpdJMSLgBEcX/C66doehYrCMroKB6eBP5GEwzV1GYRDk6qi7eYwc/50kW8jYK/NvTQKK+5x4DJZF8DsWd3TUOdyh3cvINGG+GAdNzTsJNPB1l8HQY4fHgKhgpGFnxHEKraUFg2myjtx1XQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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/