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a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1773937717; bh=H52Zybh5o34dbFpC/ZH35I3IR0TeF3CcjTZ7JtQFu2w=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=qVsoVvGZBgiMTYzcaPymyws/zFtGLAsJuSf42v3omgVhgy4V/7SM/UFdDfZU97k+C vY11I8eol4oictnvBu/vQMefqoMTn+2RHUiOztqmT14YgkRFwnc3yMPdzePNXNxnxC Y01VMPNtIKCj5VPxAbfZbdq9ZRMZ8zsrYw0n9y2U= Date: Thu, 19 Mar 2026 09:28:35 -0700 From: Jacob Pan To: Vipin Sharma Cc: David Matlack , 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 , 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: <20260319092835.00004887@linux.microsoft.com> In-Reply-To: <20260316162518.GB1767448.vipinsh@google.com> 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> <20260316162518.GB1767448.vipinsh@google.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: C1A6E120004 X-Rspamd-Server: rspam07 X-Stat-Signature: bn7xthm8huq374hx3xoprb4g8roykkj3 X-Rspam-User: X-HE-Tag: 1773937718-326769 X-HE-Meta: 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 hx/VrNtG waP927OyMf0x0AtSOe2O8fqB90nJKHcZt2HnKydmhRQBECZVy+xI5vOS7tFaGkL7O7immjKtcXQdX2lPYry46fKCbLNFOqNbloKbyaVtZl+S1uJiANv/DEkOW7XjXxz5jTCBBMvZtX+Jqqcv2ZHltGCgW2sKsX/HwmViToHYYMs2Kx8QwRu2ItNBjcyCZrguROAGTh8nOAmI/4RqEy6LZ4AB1uNQ41lt57z5qBrY2bO78DHGWb6rpz/Kf/j8wFEe3jqGxYB6FPdTGjqX3q6etujZJTT74VAlJYzi5VWUESsDh0FwAgkp0tkYR1wzZRzlNzzXzRmomBD3xi7GCwK0CnUDj8j9N4MQomMwykPPPdNpPPbi8Fn2c6MjzOFxXXshrKGvR2WucnxS8X5RVt1gUQiIGtA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Vipin, On Mon, 16 Mar 2026 09:28:32 -0700 Vipin Sharma wrote: > On Fri, Mar 13, 2026 at 08:39:18AM -0700, Jacob Pan wrote: > > Hi David, > > =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? I=E2=80=99ve tested your > > vfio_pci_liveupdate_kexec_test with the noiommu cdev, and it works > > as expected. > > =20 >=20 > Just curious, are you using qemu VM without iommu device for noiommu > work or do you have actual system without iommu hardware for testing? I am using a qemu VM without iommu device and with an assigned nvme device. I use a low level nvme userspace driver (modified to use iommufd noiommu mode) for testing. https://github.com/SamsungDS/libvfn