| Message ID | 0-v1-eaf3ccbba33c+1add0-vfio_reflck_jgg@nvidia.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Provide core infrastructure for managing open/release | expand |
On 7/15/2021 5:50 AM, Jason Gunthorpe wrote: > Prologue: > > This is the first series of three to send the "mlx5_vfio_pci" driver that has > been discussed on the list for a while now. > - Reorganize reflck to support splitting vfio_pci > - Split vfio_pci into vfio_pci/vfio_pci_core and provide infrastructure > for non-generic VFIO PCI drivers > - The new driver mlx5_vfio_pci that is a full implementation of > suspend/resume functionality for mlx5 devices. > > A preview of all the patches can be seen here: > > https://github.com/jgunthorpe/linux/commits/mlx5_vfio_pci > > =============== > > This is in support of Max's series to split vfio-pci. For that to work the > reflck concept embedded in vfio-pci needs to be sharable across all of the > new VFIO PCI drivers which motivated re-examining how this is > implemented. > > Another significant issue is how the VFIO PCI core includes code like: > > if (pci_dev_driver(pdev) != &vfio_pci_driver) > > Which is not scalable if there are going to be multiple different driver > types. > > This series takes the approach of moving the "reflck" mechanism into the > core code as a "device set". Each vfio_device driver can specify how > vfio_devices are grouped into the set using a key and the set comes along > with a set-global mutex. The core code manages creating per-device set > memory and associating it with each vfio_device. > > In turn this allows the core code to provide an open/close_device() > operation that is called only for the first/last FD, and is called under > the global device set lock. > > Review of all the drivers show that they are either already open coding > the first/last semantic or are buggy and missing it. All drivers are > migrated/fixed to the new open/close_device ops and the unused per-FD > open()/release() ops are deleted. > Why can't open()/release() ops be reused instead of adding open_device()/close_device(). Thanks, Kirti
On Thu, Jul 15, 2021 at 06:58:31PM +0530, Kirti Wankhede wrote: > > Review of all the drivers show that they are either already open coding > > the first/last semantic or are buggy and missing it. All drivers are > > migrated/fixed to the new open/close_device ops and the unused per-FD > > open()/release() ops are deleted. > > Why can't open()/release() ops be reused instead of adding > open_device()/close_device(). It could be done but it would ruin the structure of the patch series, obfuscate the naming of the ops, and complicate backporting as this is a significant semantic difference. Overall when funtionality changes significantly it is better to change the name along with it Jason
Prologue: This is the first series of three to send the "mlx5_vfio_pci" driver that has been discussed on the list for a while now. - Reorganize reflck to support splitting vfio_pci - Split vfio_pci into vfio_pci/vfio_pci_core and provide infrastructure for non-generic VFIO PCI drivers - The new driver mlx5_vfio_pci that is a full implementation of suspend/resume functionality for mlx5 devices. A preview of all the patches can be seen here: https://github.com/jgunthorpe/linux/commits/mlx5_vfio_pci =============== This is in support of Max's series to split vfio-pci. For that to work the reflck concept embedded in vfio-pci needs to be sharable across all of the new VFIO PCI drivers which motivated re-examining how this is implemented. Another significant issue is how the VFIO PCI core includes code like: if (pci_dev_driver(pdev) != &vfio_pci_driver) Which is not scalable if there are going to be multiple different driver types. This series takes the approach of moving the "reflck" mechanism into the core code as a "device set". Each vfio_device driver can specify how vfio_devices are grouped into the set using a key and the set comes along with a set-global mutex. The core code manages creating per-device set memory and associating it with each vfio_device. In turn this allows the core code to provide an open/close_device() operation that is called only for the first/last FD, and is called under the global device set lock. Review of all the drivers show that they are either already open coding the first/last semantic or are buggy and missing it. All drivers are migrated/fixed to the new open/close_device ops and the unused per-FD open()/release() ops are deleted. The special behavior of PCI around the bus/slot "reset group" is recast in terms of the device set which conslidates the reflck, eliminates two touches of pci_dev_driver(), and allows the reset mechanism to share across all VFIO PCI drivers. PCI is changed to acquire devices directly from the device set instead of trying to work backwards from the struct pci_device. Overall a few minor bugs are squashed and quite a bit of code is removed through consolidation. Jason Gunthorpe (11): vfio/samples: Remove module get/put vfio: Provide better generic support for open/release vfio_device_ops vfio/samples: Delete useless open/close vfio/fsl: Move to the device set infrastructure vfio/platform: Use open_device() instead of open coding a refcnt scheme vfio/pci: Change vfio_pci_try_bus_reset() to use the dev_set vfio/pci: Reorganize VFIO_DEVICE_PCI_HOT_RESET to use the device set vfio/mbochs: Fix close when multiple device FDs are open vfio/ap,ccw: Fix open/close when multiple device FDs are open vfio/gvt: Fix open/close when multiple device FDs are open vfio: Remove struct vfio_device_ops open/release Max Gurtovoy (1): vfio: Introduce a vfio_uninit_group_dev() API call Yishai Hadas (1): vfio/pci: Move to the device set infrastructure Documentation/driver-api/vfio.rst | 4 +- drivers/gpu/drm/i915/gvt/kvmgt.c | 8 +- drivers/s390/cio/vfio_ccw_ops.c | 8 +- drivers/s390/crypto/vfio_ap_ops.c | 8 +- drivers/vfio/fsl-mc/vfio_fsl_mc.c | 158 ++---- drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c | 6 +- drivers/vfio/fsl-mc/vfio_fsl_mc_private.h | 7 - drivers/vfio/mdev/vfio_mdev.c | 29 +- drivers/vfio/pci/vfio_pci.c | 459 ++++++------------ drivers/vfio/pci/vfio_pci_private.h | 7 - drivers/vfio/platform/vfio_platform_common.c | 86 ++-- drivers/vfio/platform/vfio_platform_private.h | 1 - drivers/vfio/vfio.c | 149 +++++- include/linux/mdev.h | 9 +- include/linux/vfio.h | 26 +- samples/vfio-mdev/mbochs.c | 16 +- samples/vfio-mdev/mdpy.c | 40 +- samples/vfio-mdev/mtty.c | 40 +- 18 files changed, 439 insertions(+), 622 deletions(-)