On Tue, Apr 21, 2026 at 10:40:29AM -0700, David Matlack wrote: > On Mon, Mar 23, 2026 at 4:58 PM David Matlack <[email protected]> wrote: > > > +static int vfio_pci_liveupdate_freeze(struct liveupdate_file_op_args *args) > > +{ > > + struct vfio_device *device = vfio_device_from_file(args->file); > > + struct vfio_pci_core_device *vdev; > > + struct pci_dev *pdev; > > + int ret; > > + > > + vdev = container_of(device, struct vfio_pci_core_device, vdev); > > + pdev = vdev->pdev; > > + > > + guard(mutex)(&device->dev_set->lock); > > + > > + /* > > + * Userspace must disable interrupts on the device prior to freeze > > so > > + * that the device does not send any interrupts until new interrupt > > + * handlers have been established by the next kernel. > > + */ > > + if (vdev->irq_type != VFIO_PCI_NUM_IRQS) { > > + pci_err(pdev, "Freeze failed! Interrupts are still > > enabled.\n"); > > + return -EINVAL; > > + } > > + > > + ret = pci_load_saved_state(pdev, vdev->pci_saved_state); > > + if (ret) > > + return ret; > > + > > + vfio_pci_core_try_reset(vdev); > > 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.. Didn't look beyond this hunk but why is a function called 'freeze' donig a reset anyhow? > Sashiko also wondered if pci_clear_master() is needed to ensure that > the device has bus mastering disabled during the kexec Only devices that are not being preserved.. > think that is actually an issue. vfio_pci_core_enable() makes sure > that vdev->pci_saved_state has bus mastering disabled, so > pci_restore_state() below here should guaranteed it is clear during > kexec. .. and bus mastering should not be disabled on any device expecting to be preserved .. Jason
