On Mon, 2014-07-21 at 14:11 +0000, Yuval Mintz wrote: > > > > >> > > > pci_iov_assign_device(), > > > > >> > > > pci_iov_deassign_device() > > > > >> > > > > > > > >> > > > along with the existed one > > > > >> > > > > > > > >> > > > pci_vfs_assigned() > > > > >> > > > > > > > >> > > > They construct the VFs assignment management interface, > > > > >> perhaps it's the right place to add some sort of mechanism in > > > > >> order to prevent module removal once one of its VFs is assigned. > > > > >> [e.g., incrementing module reference count] > > > > >> > > > > > On what module would the reference count be increased, the PF? > > > > > The entire "VF assigned" interface is a hack to work around poor > > > > > architectures like legacy KVM device assignment where there's no > > > > > proper device owner for the VF. This is "fixed" by using VFIO > > > > > instead and hopefully deprecating legacy KVM assignment. Thanks, > > > > > > > > To explain what Alex said, in another word, if VMs access VF via > > > > VFIO driver, the owner of the device is VFIO, in this case, if you > > > > unload PF driver, you still need to unload VFIO first, then unload > > > > PF driver. but the PF driver knows how to notify the VFIO driver to > > > > unload. > > > > But without VFIO like driver, for example some of current code > > > > will assign devcie (PF/VF) directly to KVM or XEN without driver in > > > > the middle. and the PF driver doesn't know how to unbind the > > > > assignment... > > > > > > I thought about perhaps incrementing the reference count of the PF's > > > module [i.e., the module supplying the driver for the PF] directly, so > > > THAT module won't be removable as long as the VF is assigned. > > > > > > Although I don't know whether the module is even accessible; Can you > > > derive a pointer to a module from a net_device struct? > > > > A VF is not necessarily a net device. A pci_dev does have a physfn pointer > > though. > > I stand corrected. > > Is there anything inherently wrong about this approach, though?
What does incrementing the module reference on the PF driver accomplish? We can still unbind the PF device from the driver. That's what this "VF used" flag is supposed to accomplish is preventing the PF from unbinding from the driver while VFs are in use, but as has been noted, it's a terrible hack. BTW, the below corporate disclaimer below is really inappropriate for the mailing list. Thanks, Alex > ________________________________ > > This message and any attached documents contain information from > QLogic Corporation or its wholly-owned subsidiaries that may be > confidential. If you are not the intended recipient, you may not read, > copy, distribute, or use this information. If you have received this > transmission in error, please notify the sender immediately by reply > e-mail and then delete this message. ------------------------------------------------------------------------------ Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds _______________________________________________ E1000-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
