> -----Original Message----- > From: Alex Williamson <alex.williamson@xxxxxxxxxx> > Sent: Friday, March 31, 2023 9:25 PM > To: Jiang, Yanting <yanting.jiang@xxxxxxxxx> > Cc: Liu, Yi L <yi.l.liu@xxxxxxxxx>; jgg@xxxxxxxxxx; Tian, Kevin > <kevin.tian@xxxxxxxxx>; joro@xxxxxxxxxx; robin.murphy@xxxxxxx; > cohuck@xxxxxxxxxx; eric.auger@xxxxxxxxxx; nicolinc@xxxxxxxxxx; > kvm@xxxxxxxxxxxxxxx; mjrosato@xxxxxxxxxxxxx; chao.p.peng@xxxxxxxxxxxxxxx; > yi.y.sun@xxxxxxxxxxxxxxx; peterx@xxxxxxxxxx; jasowang@xxxxxxxxxx; > shameerali.kolothum.thodi@xxxxxxxxxx; lulu@xxxxxxxxxx; > suravee.suthikulpanit@xxxxxxx; intel-gvt-dev@xxxxxxxxxxxxxxxxxxxxx; intel- > gfx@xxxxxxxxxxxxxxxxxxxxx; linux-s390@xxxxxxxxxxxxxxx; Hao, Xudong > <xudong.hao@xxxxxxxxx>; Zhao, Yan Y <yan.y.zhao@xxxxxxxxx>; Xu, Terrence > <terrence.xu@xxxxxxxxx> > Subject: Re: [PATCH v2 00/10] Introduce new methods for verifying ownership in > vfio PCI hot reset > > On Fri, 31 Mar 2023 03:14:23 +0000 > "Jiang, Yanting" <yanting.jiang@xxxxxxxxx> wrote: > > > > > > > VFIO_DEVICE_PCI_HOT_RESET requires user to pass an array of group > > > fds to prove that it owns all devices affected by resetting the > > > calling device. This series introduces several extensions to allow > > > the ownership check better aligned with iommufd and coming vfio device > cdev support. > > > > > > First, resetting an unopened device is always safe given nobody is > > > using it. So relax the check to allow such devices not covered by > > > group fd array. [1] > > > > > > When iommufd is used we can simply verify that all affected devices > > > are bound to a same iommufd then no need for the user to provide extra fd > information. > > > This is enabled by the user passing a zero-length fd array and > > > moving forward this should be the preferred way for hot reset. [2] > > > > > > However the iommufd method has difficulty working with noiommu > > > devices since those devices don't have a valid iommufd, unless the > > > noiommu device is in a singleton dev_set hence no ownership check is > > > required. [3] > > > > > > For noiommu backward compatibility a 3rd method is introduced by > > > allowing the user to pass an array of device fds to prove ownership. > > > [4] > > > > > > As suggested by Jason [5], we have this series to introduce the > > > above stuffs to the vfio PCI hot reset. Per the dicussion in [6], > > > this series also adds a new _INFO ioctl to get hot reset scope for given > device. > > > > > Tested NIC passthrough on Intel platform. > > Result looks good hence, > > Tested by: Jiang, Yanting <yanting.jiang@xxxxxxxxx> > > I'm not aware of any userspace that exercises this reset ioctl in cdev mode. Is > this regression testing only? Thanks, > > Alex Hi Alex, Yes, only regression testing and some negative testing for NIC passthrough with legacy vfio mode, vfio iommufd compat mode, and cdev mode. Thanks, Yanting
