From: Jason Gunthorpe <jgg@nvidia.com>
To: David Matlack <dmatlack@google.com>
Cc: "Alex Williamson" <alex@shazbot.org>,
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"William Tu" <witu@nvidia.com>, "Yi Liu" <yi.l.liu@intel.com>,
"Zhu Yanjun" <yanjun.zhu@linux.dev>
Subject: Re: [PATCH v3 07/24] vfio/pci: Preserve vfio-pci device files across Live Update
Date: Tue, 21 Apr 2026 16:20:42 -0300 [thread overview]
Message-ID: <20260421192042.GH3199414@nvidia.com> (raw)
In-Reply-To: <CALzav=cFarR4q7NugCxXwCW6wnyU9dJRaaTnxs7MY5ia5SDJWQ@mail.gmail.com>
On Tue, Apr 21, 2026 at 12:02:51PM -0700, David Matlack wrote:
> > > I think a call to pci_clear_master() is needed here to so the device
> > > stops issuing memory transactions while VFIO is trying to resetting
> > > it.
> >
> > That doesn't sound right, reset should always work..
>
> pcie_flr() calls pci_wait_for_pending_transaction() which times out
> and prints an error message. The reset seems to be working fine though
> after that.
Wow, that doesn't sound right in more ways :)
pci_reset_function() just calls straight down to that and it is
directly tied into the sysfs reset file.
Meaning the sysfs doesn't work if the device is actively doing DMA?
Feels wrong!
However it has been like that since 2008 so I probably wouldn't touch
it and agree that disabling busmastering appears to be an undocumented
requirement.
Jason
next prev parent reply other threads:[~2026-04-21 19:21 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-23 23:57 [PATCH v3 00/24] vfio/pci: Base Live Update support for VFIO device files David Matlack
2026-03-23 23:57 ` [PATCH v3 01/24] liveupdate: Export symbols needed by modules David Matlack
2026-03-23 23:57 ` [PATCH v3 02/24] PCI: Add API to track PCI devices preserved across Live Update David Matlack
2026-03-25 20:06 ` David Matlack
2026-03-25 23:12 ` Bjorn Helgaas
2026-03-26 21:39 ` David Matlack
2026-03-30 22:54 ` Bjorn Helgaas
2026-03-31 17:33 ` Samiullah Khawaja
2026-04-02 21:28 ` Yanjun.Zhu
2026-04-03 17:24 ` Chris Li
2026-04-03 21:58 ` David Matlack
2026-04-05 16:56 ` Zhu Yanjun
2026-04-06 16:06 ` David Matlack
2026-04-06 18:09 ` Yanjun.Zhu
2026-03-23 23:57 ` [PATCH v3 03/24] PCI: Require Live Update preserved devices are in singleton iommu_groups David Matlack
2026-03-24 13:07 ` Yi Liu
2026-03-24 18:00 ` David Matlack
2026-03-25 11:12 ` Yi Liu
2026-03-25 17:29 ` David Matlack
2026-03-25 23:13 ` Bjorn Helgaas
2026-03-23 23:57 ` [PATCH v3 04/24] PCI: Inherit bus numbers from previous kernel during Live Update David Matlack
2026-03-23 23:57 ` [PATCH v3 05/24] docs: liveupdate: Add documentation for PCI David Matlack
2026-03-23 23:57 ` [PATCH v3 06/24] vfio/pci: Register a file handler with Live Update Orchestrator David Matlack
2026-03-24 13:07 ` Yi Liu
2026-03-24 16:33 ` David Matlack
2026-03-23 23:57 ` [PATCH v3 07/24] vfio/pci: Preserve vfio-pci device files across Live Update David Matlack
2026-03-24 13:08 ` Yi Liu
2026-03-24 16:46 ` David Matlack
2026-03-27 23:39 ` Samiullah Khawaja
2026-04-21 17:40 ` David Matlack
2026-04-21 18:44 ` Jason Gunthorpe
2026-04-21 19:02 ` David Matlack
2026-04-21 19:20 ` Jason Gunthorpe [this message]
2026-03-23 23:58 ` [PATCH v3 08/24] vfio/pci: Retrieve preserved device files after " David Matlack
2026-03-24 13:08 ` Yi Liu
2026-03-24 17:05 ` David Matlack
2026-03-23 23:58 ` [PATCH v3 09/24] vfio/pci: Notify PCI subsystem about devices preserved across " David Matlack
2026-03-23 23:58 ` [PATCH v3 10/24] vfio: Enforce preserved devices are retrieved via LIVEUPDATE_SESSION_RETRIEVE_FD David Matlack
2026-03-23 23:58 ` [PATCH v3 11/24] vfio/pci: Store incoming Live Update state in struct vfio_pci_core_device David Matlack
2026-03-23 23:58 ` [PATCH v3 12/24] vfio/pci: Skip reset of preserved device after Live Update David Matlack
2026-03-23 23:58 ` [PATCH v3 13/24] docs: liveupdate: Add documentation for VFIO PCI David Matlack
2026-03-23 23:58 ` [PATCH v3 14/24] selftests/liveupdate: Move luo_test_utils.* into a reusable library David Matlack
2026-03-23 23:58 ` [PATCH v3 15/24] selftests/liveupdate: Add helpers to preserve/retrieve FDs David Matlack
2026-03-23 23:58 ` [PATCH v3 16/24] vfio: selftests: Build liveupdate library in VFIO selftests David Matlack
2026-03-23 23:58 ` [PATCH v3 17/24] vfio: selftests: Add Makefile support for TEST_GEN_PROGS_EXTENDED David Matlack
2026-03-23 23:58 ` [PATCH v3 18/24] vfio: selftests: Add vfio_pci_liveupdate_uapi_test David Matlack
2026-03-23 23:58 ` [PATCH v3 19/24] vfio: selftests: Initialize vfio_pci_device using a VFIO cdev FD David Matlack
2026-03-23 23:58 ` [PATCH v3 20/24] vfio: selftests: Add vfio_pci_liveupdate_kexec_test David Matlack
2026-03-23 23:58 ` [PATCH v3 21/24] vfio: selftests: Expose iommu_modes to tests David Matlack
2026-03-23 23:58 ` [PATCH v3 22/24] vfio: selftests: Expose low-level helper routines for setting up struct vfio_pci_device David Matlack
2026-03-23 23:58 ` [PATCH v3 23/24] vfio: selftests: Verify that opening VFIO device fails during Live Update David Matlack
2026-03-23 23:58 ` [PATCH v3 24/24] vfio: selftests: Add continuous DMA to vfio_pci_liveupdate_kexec_test David Matlack
2026-03-24 6:42 ` [PATCH v3 00/24] vfio/pci: Base Live Update support for VFIO device files Askar Safin
2026-03-26 20:43 ` David Matlack
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