| Message ID | 0-v4-9ea22c5e6afb+1adf-vfio_reflck_jgg@nvidia.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Provide core infrastructure for managing open/release | expand |
On Thu, 5 Aug 2021 22:18:56 -0300 Jason Gunthorpe <jgg@nvidia.com> wrote: > 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. > > v4: > - Fix use-after-free typo in mbochs error unwind > - Allow mdevs to work when they don't have open/release ops, for > bisect-ability > - Redo the vfio_pci_try_bus_reset() patch, make it dev_set centric > - Change VFIO_DEVICE_PCI_HOT_RESET to align with the new > vfio_pci_try_bus_reset() design Applied to vfio next branch for v5.15 with Connie and Christoph's additional Reviewed-bys. Thanks, Alex
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. v4: - Fix use-after-free typo in mbochs error unwind - Allow mdevs to work when they don't have open/release ops, for bisect-ability - Redo the vfio_pci_try_bus_reset() patch, make it dev_set centric - Change VFIO_DEVICE_PCI_HOT_RESET to align with the new vfio_pci_try_bus_reset() design v3: https://lore.kernel.org/r/0-v3-6c9e19cc7d44+15613-vfio_reflck_jgg@nvidia.com - Atomic conversion of mbochs_used_mbytes - Add missing vfio_uninit_group_dev in error unwind of mbochs - Reorganize vfio_assign_device_set() - Move the dev_set_list hunks to the introduction of the dev_set - Use if instead of ?: in fsl - Add a comment about the whole bus reset in vfio_pci_probe() - Rename vfio_pci_check_all_devices_bound() to vfio_pci_is_device_in_set() - Move logic from vfio_pci_try_bus_reset() into vfio_pci_find_reset_target() v2: https://lore.kernel.org/r/0-v2-b6a5582525c9+ff96-vfio_reflck_jgg@nvidia.com - Reorder fsl and mbochs vfio_uninit_group_dev - Fix missing error unwind in mbochs - Return 0 from mdev open_device if there is no op - Fix style for else {} - Spelling fix for singleton - Acquire cur_mem under lock - Always use error unwind flow for vfio_pci_check_all_devices_bound() v1: https://lore.kernel.org/r/0-v1-eaf3ccbba33c+1add0-vfio_reflck_jgg@nvidia.com Jason Gunthorpe (12): vfio/samples: Remove module get/put vfio/mbochs: Fix missing error unwind of mbochs_used_mbytes 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 | 161 +----- 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 | 33 +- drivers/vfio/pci/vfio_pci.c | 539 +++++++----------- drivers/vfio/pci/vfio_pci_private.h | 7 - drivers/vfio/platform/vfio_platform_common.c | 102 ++-- drivers/vfio/platform/vfio_platform_private.h | 1 - drivers/vfio/vfio.c | 142 ++++- include/linux/mdev.h | 9 +- include/linux/vfio.h | 26 +- samples/vfio-mdev/mbochs.c | 40 +- samples/vfio-mdev/mdpy.c | 40 +- samples/vfio-mdev/mtty.c | 40 +- 18 files changed, 509 insertions(+), 672 deletions(-) base-commit: 3fb1712d85962f81265b5018922a2da13cdf6033