[Intel-gfx] [PATCH v11 00/23] Add vfio_device cdev for iommufd support
Duan, Zhenzhong
zhenzhong.duan at intel.com
Tue May 23 07:42:45 UTC 2023
>-----Original Message-----
>From: Liu, Yi L <yi.l.liu at intel.com>
>Sent: Saturday, May 13, 2023 9:28 PM
>To: alex.williamson at redhat.com; jgg at nvidia.com; Tian, Kevin
><kevin.tian at intel.com>
>Cc: joro at 8bytes.org; robin.murphy at arm.com; cohuck at redhat.com;
>eric.auger at redhat.com; nicolinc at nvidia.com; kvm at vger.kernel.org;
>mjrosato at linux.ibm.com; chao.p.peng at linux.intel.com; Liu, Yi L
><yi.l.liu at intel.com>; yi.y.sun at linux.intel.com; peterx at redhat.com;
>jasowang at redhat.com; shameerali.kolothum.thodi at huawei.com;
>lulu at redhat.com; suravee.suthikulpanit at amd.com; intel-gvt-
>dev at lists.freedesktop.org; intel-gfx at lists.freedesktop.org; linux-
>s390 at vger.kernel.org; Hao, Xudong <xudong.hao at intel.com>; Zhao, Yan Y
><yan.y.zhao at intel.com>; Xu, Terrence <terrence.xu at intel.com>; Jiang,
>Yanting <yanting.jiang at intel.com>; Duan, Zhenzhong
><zhenzhong.duan at intel.com>; clegoate at redhat.com
>Subject: [PATCH v11 00/23] Add vfio_device cdev for iommufd support
>
>Existing VFIO provides group-centric user APIs for userspace. Userspace opens
>the /dev/vfio/$group_id first before getting device fd and hence getting access
>to device. This is not the desired model for iommufd. Per the conclusion of
>community discussion[1], iommufd provides device-centric kAPIs and requires
>its consumer (like VFIO) to be device-centric user APIs. Such user APIs are used
>to associate device with iommufd and also the I/O address spaces managed
>by the iommufd.
>
>This series first introduces a per device file structure to be prepared for
>further enhancement and refactors the kvm-vfio code to be prepared for
>accepting device file from userspace. After this, adds a mechanism for
>blocking device access before iommufd bind. Then refactors the vfio to be
>able to handle cdev path (e.g. iommufd binding, no-iommufd, [de]attach ioas).
>This refactor includes making the device_open exclusive between the group
>and the cdev path, only allow single device open in cdev path; vfio-iommufd
>code is also refactored to support cdev. e.g. split the vfio_iommufd_bind()
>into two steps. Eventually, adds the cdev support for vfio device and the new
>ioctls, then makes group infrastructure optional as it is not needed when vfio
>device cdev is compiled.
>
>This series is based on some preparation works done to vfio emulated
>devices[2] and vfio pci hot reset enhancements[3].
>
>This series is a prerequisite for iommu nesting for vfio device[4] [5].
>
>The complete code can be found in below branch, simple tests done to the
>legacy group path and the cdev path. Draft QEMU branch can be found at[6]
>However, the noiommu mode test is only done with some hacks in kernel and
>qemu to check if qemu can boot with noiommu devices.
>
>https://github.com/yiliu1765/iommufd/tree/vfio_device_cdev_v11
>(config CONFIG_IOMMUFD=y CONFIG_VFIO_DEVICE_CDEV=y)
>
>base-commit: b8b967d5ec691bddb883ab2abbfb8d632c97052e
>
>[1]
>https://lore.kernel.org/kvm/BN9PR11MB5433B1E4AE5B0480369F97178C189
>@BN9PR11MB5433.namprd11.prod.outlook.com/
>[2] https://lore.kernel.org/kvm/20230327093351.44505-1-yi.l.liu@intel.com/ -
>merged [3] https://lore.kernel.org/kvm/20230513132136.15021-1-
>yi.l.liu at intel.com/
>[4] https://lore.kernel.org/linux-iommu/20230511143844.22693-1-
>yi.l.liu at intel.com/
>[5] https://lore.kernel.org/linux-iommu/20230511145110.27707-1-
>yi.l.liu at intel.com/#t
>[6]
>https://github.com/yiliu1765/qemu/tree/iommufd_rfcv4.mig.reset.v4_var3
>
>Change log:
>
>v11:
> - Add back the noiommu determination at vfio device registration patch and
> put it prior to compiling vfio_group code optionally as compiling vfio_group
> optionaly is the major reason for it.
> - Fix a typo related to SPAPR (Cédric Le Goater)
> - Add t-b from Shameerali Kolothum Thodi, tested on HiSilicon D06(ARM64)
>platform
> with a NIC pass-through
>
>v10: https://lore.kernel.org/kvm/20230426150321.454465-1-
>yi.l.liu at intel.com/
> - Drop patch 03 of v9 as vfio_file_is_group() is still needed by pci hot reset
>path
> - Drop 11 of v9 per the change of noiommu support
> - Move patch 18 of v9 to hot-reset series [3]
> - vfio_file_has_device_access() is dropped as no usage now (hot-reset does
>not accept
> device fd, hence no need for this helper)
> - Minor change to patch 02, mainly make it back to patch v2 of v6 which is
>before
> splitting hot-reset series
> - Minor change in 10 and 11 due to rebase
> - Functional changes in patch 19, 20 and 21 per the latest noiommu support
> policy. noiommu device can be bound to valid iommufd now, this is different
> from the prior policy in which noiommu device is not allowed to be bound to
> valid iommufd. So may pay more attention on the three patches, previous r-
>b
> and t-b are dropped for these three patches.
>
>v9: https://lore.kernel.org/kvm/20230401151833.124749-1-yi.l.liu@intel.com/
> - Use smp_load_acquire() in vfio_file_has_device_access() for df-
>>access_granted (Alex)
> - Fix lock init in patch 16 of v8 (Jon Pan-Doh)
> - Split patch 20 of v8 (Alex)
> - Refine noiommu logic in BIND_IOMMUFD (Alex)
> - Remove dev_cookie in BIND_IOMMUFD ioctl (Alex, Jason)
> - Remove static_assert in ATTACH/DETACH ioctl handling (Alex)
> - Remove device->ops->bind_iommufd presence check in
>BIND_IOMMUFD/ATTACH/DETACH handling (Alex)
> - Remove VFIO dependecny for VFIO_CONTAINER as VFIO_GROUP should
>imply it (Alex)
> - Improve the documentation per suggestions from Alex on patch 24 of v8
>(Alex)
> - Remove WARN_ON(df->group) in vfio_device_group_uses_container() of
>patch 11
> - Add r-b from Kevin to patch 18/19 of v8
> - Add r-b from Jason to patch 03/10/11 of v8
> - Add t-b from Yanting Jiang and Nicolin Chen
>
>v8: https://lore.kernel.org/kvm/20230327094047.47215-1-yi.l.liu@intel.com/
> - Add patch 18 to determine noiommu device at vfio_device registration
>(Jason)
> - Add patch 19 to name noiommu device with "noiommu-" prefix to be par
>with
> group path
> - Add r-b from Kevin
> - Add t-b from Terrence
>
>v7: https://lore.kernel.org/kvm/20230316125534.17216-1-yi.l.liu@intel.com/
> - Split the vfio-pci hot reset changes to be separate patch series (Jason, Kevin)
> - More polish on no-iommufd support (patch 11 - 13) in cdev path (Kevin)
> - iommufd_access_detach() in patch 16 is added by Nic for emulated devices
>(Kevin, Jason)
>
>v6: https://lore.kernel.org/kvm/20230308132903.465159-1-
>yi.l.liu at intel.com/#t
> - Add r-b from Jason on patch 01 - 08 and 13 in v5
> - Based on the prerequisite mini-series which makes vfio emulated devices
> be prepared to cdev (Jason)
> - Add the approach to pass a set of device fds to do hot reset ownership
> check, while the zero-length array approach is also kept. (Jason, Kevin, Alex)
> - Drop patch 10 of v5, it is reworked by patch 13 and 17 in v6 (Jason)
> - Store vfio_group pointer in vfio_device_file to check if user is using
> legacy vfio container (Jason)
> - Drop the is_cdev_device flag (introduced in patch 14 of v5) as the group
> pointer stored in vfio_device_file can cover it.
> - Add iommu_group check in the cdev no-iommu path patch 24 (Kevin)
> - Add t-b from Terrence, Nicolin and Matthew (thanks for the help, some
>patches
> are new in this version, so I just added t-b to the patches that are also
> in v5 and no big change, for others would add in this version).
>
>v5: https://lore.kernel.org/kvm/20230227111135.61728-1-yi.l.liu@intel.com/
> - Add r-b from Kevin on patch 08, 13, 14, 15 and 17.
> - Rename patch 02 to limit the change for KVM facing kAPIs. The vfio pci
> hot reset path only accepts group file until patch 09. (Kevin)
> - Update comment around smp_load_acquire(&df->access_granted) (Yan)
> - Adopt Jason's suggestion on the vfio pci hot reset path, passing zero-length
> fd array to indicate using bound iommufd_ctx as ownership check. (Jason,
>Kevin)
> - Direct read df->access_granted value in vfio_device_cdev_close() (Kevin, Yan,
>Jason)
> - Wrap the iommufd get/put into a helper to refine the error path of
> vfio_device_ioctl_bind_iommufd(). (Yan)
>
>v4: https://lore.kernel.org/kvm/20230221034812.138051-1-yi.l.liu@intel.com/
> - Add r-b from Kevin on patch 09/10
> - Add a line in devices/vfio.rst to emphasize user should add group/device to
> KVM prior to invoke open_device op which may be called in the
>VFIO_GROUP_GET_DEVICE_FD
> or VFIO_DEVICE_BIND_IOMMUFD ioctl.
> - Modify VFIO_GROUP/VFIO_DEVICE_CDEV Kconfig dependency (Alex)
> - Select VFIO_GROUP for SPAPR (Jason)
> - Check device fully-opened in PCI hotreset path for device fd (Jason)
> - Set df->access_granted in the caller of vfio_device_open() since
> the caller may fail in other operations, but df->access_granted
> does not allow a true to false change. So it should be set only when
> the open path is really done successfully. (Yan, Kevin)
> - Fix missing iommufd_ctx_put() in the cdev path (Yan)
> - Fix an issue found in testing exclusion between group and cdev path.
> vfio_device_cdev_close() should check df->access_granted before heading
> to other operations.
> - Update vfio.rst for iommufd/cdev
>
>v3: https://lore.kernel.org/kvm/20230213151348.56451-1-yi.l.liu@intel.com/
> - Add r-b from Kevin on patch 03, 06, 07, 08.
> - Refine the group and cdev path exclusion. Remove vfio_device:single_open;
> add vfio_group::cdev_device_open_cnt to achieve exlucsion between group
> path and cdev path (Kevin, Jason)
> - Fix a bug in the error handling path (Yan Zhao)
> - Address misc remarks from Kevin
>
>v2: https://lore.kernel.org/kvm/20230206090532.95598-1-yi.l.liu@intel.com/
> - Add r-b from Kevin and Eric on patch 01 02 04.
> - "Split kvm/vfio: Provide struct kvm_device_ops::release() insted
>of ::destroy()"
> from this series and got applied. (Alex, Kevin, Jason, Mathhew)
> - Add kvm_ref_lock to protect vfio_device_file->kvm instead of reusing
> dev_set->lock as dead-lock is observed with vfio-ap which would try to
> acquire kvm_lock. This is opposite lock order with kvm_device_release()
> which holds kvm_lock first and then hold dev_set->lock. (Kevin)
> - Use a separate ioctl for detaching IOAS. (Alex)
> - Rename vfio_device_file::single_open to be is_cdev_device (Kevin, Alex)
> - Move the vfio device cdev code into device_cdev.c and add a
>VFIO_DEVICE_CDEV
> kconfig for it. (Kevin, Jason)
>
>v1: https://lore.kernel.org/kvm/20230117134942.101112-1-yi.l.liu@intel.com/
> - Fix the circular refcount between kvm struct and device file reference.
>(JasonG)
> - Address comments from KevinT
> - Remained the ioctl for detach, needs to Alex's taste
>
>(https://lore.kernel.org/kvm/BN9PR11MB5276BE9F4B0613EE859317028CFF9
>@BN9PR11MB5276.namprd11.prod.outlook.com/)
>
>rfc: https://lore.kernel.org/kvm/20221219084718.9342-1-yi.l.liu@intel.com/
>
>Thanks,
> Yi Liu
>
>Nicolin Chen (1):
> iommufd/device: Add iommufd_access_detach() API
>
>Yi Liu (22):
> vfio: Allocate per device file structure
> vfio: Refine vfio file kAPIs for KVM
> vfio: Accept vfio device file in the KVM facing kAPI
> kvm/vfio: Rename kvm_vfio_group to prepare for accepting vfio device
> fd
> kvm/vfio: Accept vfio device file from userspace
> vfio: Pass struct vfio_device_file * to vfio_device_open/close()
> vfio: Block device access via device fd until device is opened
> vfio: Add cdev_device_open_cnt to vfio_group
> vfio: Make vfio_device_open() single open for device cdev path
> vfio-iommufd: Move noiommu compat probe out of vfio_iommufd_bind()
> vfio-iommufd: Split bind/attach into two steps
> vfio: Record devid in vfio_device_file
> vfio-iommufd: Add detach_ioas support for physical VFIO devices
> vfio-iommufd: Add detach_ioas support for emulated VFIO devices
> vfio: Name noiommu vfio_device with "noiommu-" prefix
> vfio: Move vfio_device_group_unregister() to be the first operation in
> unregister
> vfio: Add cdev for vfio_device
> vfio: Add VFIO_DEVICE_BIND_IOMMUFD
> vfio: Add VFIO_DEVICE_[AT|DE]TACH_IOMMUFD_PT
> vfio: Determine noiommu device in __vfio_register_dev()
> vfio: Compile vfio_group infrastructure optionally
> docs: vfio: Add vfio device cdev description
>
> Documentation/driver-api/vfio.rst | 140 +++++++++-
> Documentation/virt/kvm/devices/vfio.rst | 47 ++--
> drivers/gpu/drm/i915/gvt/kvmgt.c | 1 +
> drivers/iommu/iommufd/Kconfig | 4 +-
> drivers/iommu/iommufd/device.c | 76 +++++-
> drivers/iommu/iommufd/iommufd_private.h | 2 +
> drivers/s390/cio/vfio_ccw_ops.c | 1 +
> drivers/s390/crypto/vfio_ap_ops.c | 1 +
> drivers/vfio/Kconfig | 25 ++
> drivers/vfio/Makefile | 3 +-
> drivers/vfio/device_cdev.c | 258 ++++++++++++++++++
> drivers/vfio/fsl-mc/vfio_fsl_mc.c | 1 +
> drivers/vfio/group.c | 150 ++++++----
> drivers/vfio/iommufd.c | 125 ++++++---
> .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 2 +
> drivers/vfio/pci/mlx5/main.c | 1 +
> drivers/vfio/pci/vfio_pci.c | 1 +
> drivers/vfio/pci/vfio_pci_core.c | 16 +-
> drivers/vfio/platform/vfio_amba.c | 1 +
> drivers/vfio/platform/vfio_platform.c | 1 +
> drivers/vfio/vfio.h | 238 ++++++++++++++--
> drivers/vfio/vfio_main.c | 225 +++++++++++++--
> include/linux/iommufd.h | 1 +
> include/linux/vfio.h | 45 ++-
> include/uapi/linux/kvm.h | 13 +-
> include/uapi/linux/vfio.h | 80 ++++++
> samples/vfio-mdev/mbochs.c | 1 +
> samples/vfio-mdev/mdpy.c | 1 +
> samples/vfio-mdev/mtty.c | 1 +
> virt/kvm/vfio.c | 137 +++++-----
> 30 files changed, 1365 insertions(+), 233 deletions(-) create mode 100644
>drivers/vfio/device_cdev.c
>
>--
>2.34.1
Tested noiommu mode in two ways, both tests passed.
One way is an ixgbe card in noiommu mode passthroughed to guest without doing DMA(need changing qemu to open noiommu device).
The other way is same ixgbe card used in DPDK to receive packages from another server.
Tested-by: Zhenzhong Duan <zhenzhong.duan at intel.com>
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