On Tue, 2014-11-11 at 14:09 -0500, Don Dutile wrote: > On 11/10/2014 06:53 AM, Sathya Perla wrote: > > A user must not be allowed to disable VFs while they are already assigned to > > a guest. This check is being made in each individual driver that implements > > the sriov_configure PCI method. > > This patch-set fixes this code duplication by moving this check from > > drivers to the sriov_nuvfs_store() routine just before invoking > > sriov_configure() when num_vfs is equal to 0. > > > > Vasundhara Volam (4): > > pci: move pci_assivned_vfs() check while disabling VFs to pci > > sub-system > > bnx2x: remove pci_assigned_vfs() check while disabling VFs > > i40e: remove pci_assigned_vfs() check while disabling VFs > > qlcnic: remove pci_assigned_vfs() check while disabling VFs > > > > drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.c | 2 +- > > drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c | 7 +------ > > .../net/ethernet/qlogic/qlcnic/qlcnic_sriov_pf.c | 10 ---------- > > drivers/pci/pci-sysfs.c | 5 +++++ > > 4 files changed, 7 insertions(+), 17 deletions(-) > > > I have had a side conversation with Alex Williamson, VFIO author. > > VFIO is the upstream method that device-assignment is managed/handled on kvm now. > It does not set the PCI_DEV_FLAGS_ASSIGNED pci dev-flags, and thus, > this check will not work when VFIO is used. > > This patch set will only work for the former, kvm-managed, device-assignment method, > which is currently being deprecated in qemu as well. > > So, yes, it works for kvm managed device-assignment, but not the > newer, VFIO-based device-assignment. > > Note, also, that the pci_assigned_vfs() check in the drivers will > always return 0 when VFIO is used for device assignment, so keeping > these checks in the drivers doesn't do what they imply either. > > So, taking in the patch solves old, kvm-managed, device assignment, > but a new method is needed when VFIO is involved. > > - Don > > ps -- Note: just adding the flag setting in vfio-pci does not necessarily > solve this problem. VFIO does not know if a device is assigned to a guest; > it only knows a caller of the ioctl requesting the device to be assigned > to vfio, and to be dma-mapped for a region of memory, has been requested. > So, a new PF<->VF mechanism needs to be put in place to > determine the equivalent information. pps -- Note: testing pci_assivned_vfs() is racy, nothing prevents the flag being added to a device between your check and removing the VF device. This is one of the reasons that vfio-pci doesn't use it and that this interface should be discouraged in the kernel. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
