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2020-03-24Merge branches 'v5.7/vfio/alex-sriov-v3' and 'v5.7/vfio/yan-dma-rw-v4' into ↵Alex Williamson
v5.7/vfio/next
2020-03-24vfio: Include optional device match in vfio_device_ops callbacksAlex Williamson
Allow bus drivers to provide their own callback to match a device to the user provided string. Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2020-03-24vfio: avoid inefficient operations on VFIO group in vfio_pin/unpin_pagesYan Zhao
vfio_group_pin_pages() and vfio_group_unpin_pages() are introduced to avoid inefficient search/check/ref/deref opertions associated with VFIO group as those in each calling into vfio_pin_pages() and vfio_unpin_pages(). VFIO group is taken as arg directly. The callers combine search/check/ref/deref operations associated with VFIO group by calling vfio_group_get_external_user()/vfio_group_get_external_user_from_dev() beforehand, and vfio_group_put_external_user() afterwards. Suggested-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Yan Zhao <yan.y.zhao@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2020-03-24vfio: introduce vfio_dma_rw to read/write a range of IOVAsYan Zhao
vfio_dma_rw will read/write a range of user space memory pointed to by IOVA into/from a kernel buffer without enforcing pinning the user space memory. TODO: mark the IOVAs to user space memory dirty if they are written in vfio_dma_rw(). Cc: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Yan Zhao <yan.y.zhao@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2020-03-24vfio: allow external user to get vfio group from deviceYan Zhao
external user calls vfio_group_get_external_user_from_dev() with a device pointer to get the VFIO group associated with this device. The VFIO group is checked to be vialbe and have IOMMU set. Then container user counter is increased and VFIO group reference is hold to prevent the VFIO group from disposal before external user exits. when the external user finishes using of the VFIO group, it calls vfio_group_put_external_user() to dereference the VFIO group and the container user counter. Suggested-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Yan Zhao <yan.y.zhao@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2019-10-23compat_ioctl: move drivers to compat_ptr_ioctlArnd Bergmann
Each of these drivers has a copy of the same trivial helper function to convert the pointer argument and then call the native ioctl handler. We now have a generic implementation of that, so use it. Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Reviewed-by: Jiri Kosina <jkosina@suse.cz> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner
Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-23vfio: Fix WARNING "do not call blocking ops when !TASK_RUNNING"Farhan Ali
vfio_dev_present() which is the condition to wait_event_interruptible_timeout(), will call vfio_group_get_device and try to acquire the mutex group->device_lock. wait_event_interruptible_timeout() will set the state of the current task to TASK_INTERRUPTIBLE, before doing the condition check. This means that we will try to acquire the mutex while already in a sleeping state. The scheduler warns us by giving the following warning: [ 4050.264464] ------------[ cut here ]------------ [ 4050.264508] do not call blocking ops when !TASK_RUNNING; state=1 set at [<00000000b33c00e2>] prepare_to_wait_event+0x14a/0x188 [ 4050.264529] WARNING: CPU: 12 PID: 35924 at kernel/sched/core.c:6112 __might_sleep+0x76/0x90 .... 4050.264756] Call Trace: [ 4050.264765] ([<000000000017bbaa>] __might_sleep+0x72/0x90) [ 4050.264774] [<0000000000b97edc>] __mutex_lock+0x44/0x8c0 [ 4050.264782] [<0000000000b9878a>] mutex_lock_nested+0x32/0x40 [ 4050.264793] [<000003ff800d7abe>] vfio_group_get_device+0x36/0xa8 [vfio] [ 4050.264803] [<000003ff800d87c0>] vfio_del_group_dev+0x238/0x378 [vfio] [ 4050.264813] [<000003ff8015f67c>] mdev_remove+0x3c/0x68 [mdev] [ 4050.264825] [<00000000008e01b0>] device_release_driver_internal+0x168/0x268 [ 4050.264834] [<00000000008de692>] bus_remove_device+0x162/0x190 [ 4050.264843] [<00000000008daf42>] device_del+0x1e2/0x368 [ 4050.264851] [<00000000008db12c>] device_unregister+0x64/0x88 [ 4050.264862] [<000003ff8015ed84>] mdev_device_remove+0xec/0x130 [mdev] [ 4050.264872] [<000003ff8015f074>] remove_store+0x6c/0xa8 [mdev] [ 4050.264881] [<000000000046f494>] kernfs_fop_write+0x14c/0x1f8 [ 4050.264890] [<00000000003c1530>] __vfs_write+0x38/0x1a8 [ 4050.264899] [<00000000003c187c>] vfs_write+0xb4/0x198 [ 4050.264908] [<00000000003c1af2>] ksys_write+0x5a/0xb0 [ 4050.264916] [<0000000000b9e270>] system_call+0xdc/0x2d8 [ 4050.264925] 4 locks held by sh/35924: [ 4050.264933] #0: 000000001ef90325 (sb_writers#4){.+.+}, at: vfs_write+0x9e/0x198 [ 4050.264948] #1: 000000005c1ab0b3 (&of->mutex){+.+.}, at: kernfs_fop_write+0x1cc/0x1f8 [ 4050.264963] #2: 0000000034831ab8 (kn->count#297){++++}, at: kernfs_remove_self+0x12e/0x150 [ 4050.264979] #3: 00000000e152484f (&dev->mutex){....}, at: device_release_driver_internal+0x5c/0x268 [ 4050.264993] Last Breaking-Event-Address: [ 4050.265002] [<000000000017bbaa>] __might_sleep+0x72/0x90 [ 4050.265010] irq event stamp: 7039 [ 4050.265020] hardirqs last enabled at (7047): [<00000000001cee7a>] console_unlock+0x6d2/0x740 [ 4050.265029] hardirqs last disabled at (7054): [<00000000001ce87e>] console_unlock+0xd6/0x740 [ 4050.265040] softirqs last enabled at (6416): [<0000000000b8fe26>] __udelay+0xb6/0x100 [ 4050.265049] softirqs last disabled at (6415): [<0000000000b8fe06>] __udelay+0x96/0x100 [ 4050.265057] ---[ end trace d04a07d39d99a9f9 ]--- Let's fix this as described in the article https://lwn.net/Articles/628628/. Signed-off-by: Farhan Ali <alifm@linux.ibm.com> [remove now redundant vfio_dev_present()] Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2019-04-22vfio: Use dev_printk() when possibleBjorn Helgaas
Use dev_printk() when possible to make messages consistent with other device-related messages. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2019-02-12vfio: expand minor range when registering chrdev regionChengguang Xu
Actually, total amount of available minor number for a single major is MINORMARK + 1. So expand minor range when registering chrdev region. Signed-off-by: Chengguang Xu <cgxu519@gmx.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2018-06-08vfio: use match_string() helperYisheng Xie
match_string() returns the index of an array for a matching string, which can be used intead of open coded variant. Cc: Alex Williamson <alex.williamson@redhat.com> Cc: kvm@vger.kernel.org Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2017-12-20vfio: Simplify capability helperAlex Williamson
The vfio_info_add_capability() helper requires the caller to pass a capability ID, which it then uses to fill in header fields, assuming hard coded versions. This makes for an awkward and rigid interface. The only thing we want this helper to do is allocate sufficient space in the caps buffer and chain this capability into the list. Reduce it to that simple task. Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> Acked-by: Zhenyu Wang <zhenyuw@linux.intel.com> Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2017-10-25locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns ↵Mark Rutland
to READ_ONCE()/WRITE_ONCE() Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-30vfio: Stall vfio_del_group_dev() for container group detachAlex Williamson
When the user unbinds the last device of a group from a vfio bus driver, the devices within that group should be available for other purposes. We currently have a race that makes this generally, but not always true. The device can be unbound from the vfio bus driver, but remaining IOMMU context of the group attached to the container can result in errors as the next driver configures DMA for the device. Wait for the group to be detached from the IOMMU backend before allowing the bus driver remove callback to complete. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2017-08-30vfio: fix noiommu vfio_iommu_group_get reference countEric Auger
In vfio_iommu_group_get() we want to increase the reference count of the iommu group. In noiommu case, the group does not exist and is allocated. iommu_group_add_device() increases the group ref count. However we then call iommu_group_put() which decrements it. This leads to a "refcount_t: underflow WARN_ON". Only decrement the ref count in case of iommu_group_add_device failure. Signed-off-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2017-07-07vfio: Remove unnecessary uses of vfio_container.group_lockAlex Williamson
The original intent of vfio_container.group_lock is to protect vfio_container.group_list, however over time it's become a crutch to prevent changes in container composition any time we call into the iommu driver backend. This introduces problems when we start to have more complex interactions, for example when a user's DMA unmap request triggers a notification to an mdev vendor driver, who responds by attempting to unpin mappings within that request, re-entering the iommu backend. We incorrectly assume that the use of read-locks here allow for this nested locking behavior, but a poorly timed write-lock could in fact trigger a deadlock. The current use of group_lock seems to fall into the trap of locking code, not data. Correct that by removing uses of group_lock that are not directly related to group_list. Note that the vfio type1 iommu backend has its own mutex, vfio_iommu.lock, which it uses to protect itself for each of these interfaces anyway. The group_lock appears to be a redundancy for these interfaces and type1 even goes so far as to release its mutex to allow for exactly the re-entrant code path above. Reported-by: Chuanxiao Dong <chuanxiao.dong@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Acked-by: Alexey Kardashevskiy <aik@ozlabs.ru> Cc: stable@vger.kernel.org # v4.10+
2017-06-28vfio: New external user group/file matchAlex Williamson
At the point where the kvm-vfio pseudo device wants to release its vfio group reference, we can't always acquire a new reference to make that happen. The group can be in a state where we wouldn't allow a new reference to be added. This new helper function allows a caller to match a file to a group to facilitate this. Given a file and group, report if they match. Thus the caller needs to already have a group reference to match to the file. This allows the deletion of a group without acquiring a new reference. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Tested-by: Eric Auger <eric.auger@redhat.com> Cc: stable@vger.kernel.org
2017-06-28vfio: Fix group release deadlockAlex Williamson
If vfio_iommu_group_notifier() acquires a group reference and that reference becomes the last reference to the group, then vfio_group_put introduces a deadlock code path where we're trying to unregister from the iommu notifier chain from within a callout of that chain. Use a work_struct to release this reference asynchronously. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Tested-by: Eric Auger <eric.auger@redhat.com> Cc: stable@vger.kernel.org
2017-06-13vfio: Use ERR_CAST() instead of open coding itDan Carpenter
It's a small cleanup to use ERR_CAST() here. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2017-03-21vfio: Rework group release notifier warningAlex Williamson
The intent of the original warning is make sure that the mdev vendor driver has removed any group notifiers at the point where the group is closed by the user. Theoretically this would be through an orderly shutdown where any devices are release prior to the group release. We can't always count on an orderly shutdown, the user can close the group before the notifier can be removed or the user task might be killed. We'd like to add this sanity test when the group is idle and the only references are from the devices within the group themselves, but we don't have a good way to do that. Instead check both when the group itself is removed and when the group is opened. A bit later than we'd prefer, but better than the current over aggressive approach. Fixes: ccd46dbae77d ("vfio: support notifier chain in vfio_group") Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Cc: <stable@vger.kernel.org> # v4.10 Cc: Jike Song <jike.song@intel.com>
2017-02-22vfio: fix a typo in comment of function vfio_pin_pagesChangbin Du
Correct the description that 'unpinned' -> 'pinned'. Signed-off-by: Changbin Du <changbin.du@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2017-02-09vfio: Replace module request with softdepAlex Williamson
Rather than doing a module request from within the init function, add a soft dependency on the available IOMMU backend drivers. This makes the dependency visible to userspace when picking modules for the ram disk. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-12-01vfio: support notifier chain in vfio_groupJike Song
Beyond vfio_iommu events, users might also be interested in vfio_group events. For example, if a vfio_group is used along with Qemu/KVM, whenever kvm pointer is set to/cleared from the vfio_group, users could be notified. Currently only VFIO_GROUP_NOTIFY_SET_KVM supported. Cc: Kirti Wankhede <kwankhede@nvidia.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Jike Song <jike.song@intel.com> [aw: remove use of new typedef] Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-12-01vfio: vfio_register_notifier: classify iommu notifierJike Song
Currently vfio_register_notifier assumes that there is only one notifier chain, which is in vfio_iommu. However, the user might also be interested in events other than vfio_iommu, for example, vfio_group. Refactor vfio_{un}register_notifier implementation to make it feasible. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com> Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Jike Song <jike.song@intel.com> [aw: merge with commit 816ca69ea9c7 ("vfio: Fix handling of error returned by 'vfio_group_get_from_dev()'"), remove typedef] Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-12-01vfio: Fix handling of error returned by 'vfio_group_get_from_dev()'Christophe JAILLET
'vfio_group_get_from_dev()' seems to return only NULL on error, not an error pointer. Fixes: 2169037dc322 ("vfio iommu: Added pin and unpin callback functions to vfio_iommu_driver_ops") Fixes: c086de818dd8 ("vfio iommu: Add blocking notifier to notify DMA_UNMAP") Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-11-21vfio: fix vfio_info_cap_add/shiftEric Auger
Capability header next field is an offset relative to the start of the INFO buffer. tmp->next is assigned the proper value but iterations implemented in vfio_info_cap_add and vfio_info_cap_shift use next as an offset between the headers. When coping with multiple capabilities this leads to an Oops. Signed-off-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-11-17vfio: Introduce vfio_set_irqs_validate_and_prepare()Kirti Wankhede
Vendor driver using mediated device framework would use same mechnism to validate and prepare IRQs. Introducing this function to reduce code replication in multiple drivers. Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Neo Jia <cjia@nvidia.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-11-17vfio: Introduce common function to add capabilitiesKirti Wankhede
Vendor driver using mediated device framework should use vfio_info_add_capability() to add capabilities. Introduced this function to reduce code duplication in vendor drivers. vfio_info_cap_shift() manipulated a data buffer to add an offset to each element in a chain. This data buffer is documented in a uapi header. Changing vfio_info_cap_shift symbol to be available to all drivers. Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Neo Jia <cjia@nvidia.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-11-17vfio iommu: Add blocking notifier to notify DMA_UNMAPKirti Wankhede
Added blocking notifier to IOMMU TYPE1 driver to notify vendor drivers about DMA_UNMAP. Exported two APIs vfio_register_notifier() and vfio_unregister_notifier(). Notifier should be registered, if external user wants to use vfio_pin_pages()/vfio_unpin_pages() APIs to pin/unpin pages. Vendor driver should use VFIO_IOMMU_NOTIFY_DMA_UNMAP action to invalidate mappings. Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Neo Jia <cjia@nvidia.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-11-17vfio iommu: Added pin and unpin callback functions to vfio_iommu_driver_opsKirti Wankhede
Added APIs for pining and unpining set of pages. These call back into backend iommu module to actually pin and unpin pages. Added two new callback functions to struct vfio_iommu_driver_ops. Backend IOMMU module that supports pining and unpinning pages for mdev devices should provide these functions. Renamed static functions in vfio_type1_iommu.c to resolve conflicts Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Neo Jia <cjia@nvidia.com> Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-11-17vfio: Common function to increment container_usersKirti Wankhede
This change rearrange functions to have common function to increment container_users Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Neo Jia <cjia@nvidia.com> Reviewed-by: Jike Song <jike.song@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-11-17vfio: Rearrange functions to get vfio_group from devKirti Wankhede
This patch rearranges functions to get vfio_group from device Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Neo Jia <cjia@nvidia.com> Reviewed-by: Jike Song <jike.song@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-07-14vfio: fix possible use after free of vfio groupIlya Lesokhin
The vfio group should be released after the vfio_group_try_dissolve_container call. The code should not rely on someone else to hold a reference on the group. Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-02-22vfio: Add capability chain helpersAlex Williamson
Allow sub-modules to easily reallocate a buffer for managing capability chains for info ioctls. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-02-22vfio: If an IOMMU backend fails, keep lookingAlex Williamson
Consider an IOMMU to be an API rather than an implementation, we might have multiple implementations supporting the same API, so try another if one fails. The expectation here is that we'll really only have one implementation per device type. For instance the existing type1 driver works with any PCI device where the IOMMU API is available. A vGPU vendor may have a virtual PCI device which provides DMA isolation and mapping through other mechanisms, but can re-use userspaces that make use of the type1 VFIO IOMMU API. This allows that to work. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-01-27vfio/noiommu: Don't use iommu_present() to track fake groupsAlex Williamson
Using iommu_present() to determine whether an IOMMU group is real or fake has some problems. First, apparently Power systems don't register an IOMMU on the device bus, so the groups and containers get marked as noiommu and then won't bind to their actual IOMMU driver. Second, I expect we'll run into the same issue as we try to support vGPUs through vfio, since they're likely to emulate this behavior of creating an IOMMU group on a virtual device and then providing a vfio IOMMU backend tailored to the sort of isolation they provide, which won't necessarily be fully compatible with the IOMMU API. The solution here is to use the existing iommudata interface to IOMMU groups, which allows us to easily identify the fake groups we've created for noiommu purposes. The iommudata we set is purely arbitrary since we're only comparing the address, so we use the address of the noiommu switch itself. Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru> Tested-by: Anatoly Burakov <anatoly.burakov@intel.com> Tested-by: Santosh Shukla <sshukla@mvista.com> Fixes: 03a76b60f8ba ("vfio: Include No-IOMMU mode") Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2015-12-21vfio: Include No-IOMMU modeAlex Williamson
There is really no way to safely give a user full access to a DMA capable device without an IOMMU to protect the host system. There is also no way to provide DMA translation, for use cases such as device assignment to virtual machines. However, there are still those users that want userspace drivers even under those conditions. The UIO driver exists for this use case, but does not provide the degree of device access and programming that VFIO has. In an effort to avoid code duplication, this introduces a No-IOMMU mode for VFIO. This mode requires building VFIO with CONFIG_VFIO_NOIOMMU and enabling the "enable_unsafe_noiommu_mode" option on the vfio driver. This should make it very clear that this mode is not safe. Additionally, CAP_SYS_RAWIO privileges are necessary to work with groups and containers using this mode. Groups making use of this support are named /dev/vfio/noiommu-$GROUP and can only make use of the special VFIO_NOIOMMU_IOMMU for the container. Use of this mode, specifically binding a device without a native IOMMU group to a VFIO bus driver will taint the kernel and should therefore not be considered supported. This patch includes no-iommu support for the vfio-pci bus driver only. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com>
2015-12-04Revert: "vfio: Include No-IOMMU mode"Alex Williamson
Revert commit 033291eccbdb ("vfio: Include No-IOMMU mode") due to lack of a user. This was originally intended to fill a need for the DPDK driver, but uptake has been slow so rather than support an unproven kernel interface revert it and revisit when userspace catches up. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2015-11-21vfio: fix a warning messageDan Carpenter
The first argument to the WARN() macro has to be a condition. I'm sort of disappointed that this code doesn't generate a compiler warning. I guess -Wformat-extra-args doesn't work in the kernel. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2015-11-04vfio: Include No-IOMMU modeAlex Williamson
There is really no way to safely give a user full access to a DMA capable device without an IOMMU to protect the host system. There is also no way to provide DMA translation, for use cases such as device assignment to virtual machines. However, there are still those users that want userspace drivers even under those conditions. The UIO driver exists for this use case, but does not provide the degree of device access and programming that VFIO has. In an effort to avoid code duplication, this introduces a No-IOMMU mode for VFIO. This mode requires building VFIO with CONFIG_VFIO_NOIOMMU and enabling the "enable_unsafe_noiommu_mode" option on the vfio driver. This should make it very clear that this mode is not safe. Additionally, CAP_SYS_RAWIO privileges are necessary to work with groups and containers using this mode. Groups making use of this support are named /dev/vfio/noiommu-$GROUP and can only make use of the special VFIO_NOIOMMU_IOMMU for the container. Use of this mode, specifically binding a device without a native IOMMU group to a VFIO bus driver will taint the kernel and should therefore not be considered supported. This patch includes no-iommu support for the vfio-pci bus driver only. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com>
2015-11-04vfio: Fix bug in vfio_device_get_from_name()Joerg Roedel
The vfio_device_get_from_name() function might return a non-NULL pointer, when called with a device name that is not found in the list. This causes undefined behavior, in my case calling an invalid function pointer later on: kernel tried to execute NX-protected page - exploit attempt? (uid: 0) BUG: unable to handle kernel paging request at ffff8800cb3ddc08 [...] Call Trace: [<ffffffffa03bd733>] ? vfio_group_fops_unl_ioctl+0x253/0x410 [vfio] [<ffffffff811efc4d>] do_vfs_ioctl+0x2cd/0x4c0 [<ffffffff811f9657>] ? __fget+0x77/0xb0 [<ffffffff811efeb9>] SyS_ioctl+0x79/0x90 [<ffffffff81001bb0>] ? syscall_return_slowpath+0x50/0x130 [<ffffffff8167f776>] entry_SYSCALL_64_fastpath+0x16/0x75 Fix the issue by returning NULL when there is no device with the requested name in the list. Cc: stable@vger.kernel.org # v4.2+ Fixes: 4bc94d5dc95d ("vfio: Fix lockdep issue") Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2015-10-27vfio: Whitelist PCI bridgesAlex Williamson
When determining whether a group is viable, we already allow devices bound to pcieport. Generalize this to include any PCI bridge device. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2015-07-24vfio: Fix lockdep issueAlex Williamson
When we open a device file descriptor, we currently have the following: vfio_group_get_device_fd() mutex_lock(&group->device_lock); open() ... if (ret) release() If we hit that error case, we call the backend driver release path, which for vfio-pci looks like this: vfio_pci_release() vfio_pci_disable() vfio_pci_try_bus_reset() vfio_pci_get_devs() vfio_device_get_from_dev() vfio_group_get_device() mutex_lock(&group->device_lock); Whoops, we've stumbled back onto group.device_lock and created a deadlock. There's a low likelihood of ever seeing this play out, but obviously it needs to be fixed. To do that we can use a reference to the vfio_device for vfio_group_get_device_fd() rather than holding the lock. There was a loop in this function, theoretically allowing multiple devices with the same name, but in practice we don't expect such a thing to happen and the code is already aborting from the loop with break on any sort of error rather than continuing and only parsing the first match anyway, so the loop was effectively unused already. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Fixes: 20f300175a1e ("vfio/pci: Fix racy vfio_device_get_from_dev() call") Reported-by: Joerg Roedel <joro@8bytes.org> Tested-by: Joerg Roedel <jroedel@suse.de>
2015-06-09vfio/pci: Fix racy vfio_device_get_from_dev() callAlex Williamson
Testing the driver for a PCI device is racy, it can be all but complete in the release path and still report the driver as ours. Therefore we can't trust drvdata to be valid. This race can sometimes be seen when one port of a multifunction device is being unbound from the vfio-pci driver while another function is being released by the user and attempting a bus reset. The device in the remove path is found as a dependent device for the bus reset of the release path device, the driver is still set to vfio-pci, but the drvdata has already been cleared, resulting in a null pointer dereference. To resolve this, fix vfio_device_get_from_dev() to not take the dev_get_drvdata() shortcut and instead traverse through the iommu_group, vfio_group, vfio_device path to get a reference we can trust. Once we have that reference, we know the device isn't in transition and we can test to make sure the driver is still what we expect, so that we don't interfere with devices we don't own. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2015-05-01vfio: Fix runaway interruptible timeoutAlex Williamson
Commit 13060b64b819 ("vfio: Add and use device request op for vfio bus drivers") incorrectly makes use of an interruptible timeout. When interrupted, the signal remains pending resulting in subsequent timeouts occurring instantly. This makes the loop spin at a much higher rate than intended. Instead of making this completely non-interruptible, we can change this into a sort of interruptible-once behavior and use the "once" to log debug information. The driver API doesn't allow us to abort and return an error code. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Fixes: 13060b64b819 Cc: stable@vger.kernel.org # v4.0
2015-03-17vfio: Split virqfd into a separate module for vfio bus driversAlex Williamson
An unintended consequence of commit 42ac9bd18d4f ("vfio: initialize the virqfd workqueue in VFIO generic code") is that the vfio module is renamed to vfio_core so that it can include both vfio and virqfd. That's a user visible change that may break module loading scritps and it imposes eventfd support as a dependency on the core vfio code, which it's really not. virqfd is intended to be provided as a service to vfio bus drivers, so instead of wrapping it into vfio.ko, we can make it a stand-alone module toggled by vfio bus drivers. This has the additional benefit of removing initialization and exit from the core vfio code. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2015-03-16vfio: put off the allocation of "minor" in vfio_create_groupZhen Lei
The next code fragment "list_for_each_entry" is not depend on "minor". With this patch, the free of "minor" in "list_for_each_entry" can be reduced, and there is no functional change. Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2015-03-16vfio: initialize the virqfd workqueue in VFIO generic codeAntonios Motakis
Now we have finally completely decoupled virqfd from VFIO_PCI. We can initialize it from the VFIO generic code, in order to safely use it from multiple independent VFIO bus drivers. Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com> Signed-off-by: Baptiste Reynal <b.reynal@virtualopensystems.com> Reviewed-by: Eric Auger <eric.auger@linaro.org> Tested-by: Eric Auger <eric.auger@linaro.org> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2015-02-10vfio: Add and use device request op for vfio bus driversAlex Williamson
When a request is made to unbind a device from a vfio bus driver, we need to wait for the device to become unused, ie. for userspace to release the device. However, we have a long standing TODO in the code to do something proactive to make that happen. To enable this, we add a request callback on the vfio bus driver struct, which is intended to signal the user through the vfio device interface to release the device. Instead of passively waiting for the device to become unused, we can now pester the user to give it up. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2015-02-06vfio: Tie IOMMU group reference to vfio groupAlex Williamson
Move the iommu_group reference from the device to the vfio_group. This ensures that the iommu_group persists as long as the vfio_group remains. This can be important if all of the device from an iommu_group are removed, but we still have an outstanding vfio_group reference; we can still walk the empty list of devices. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-24 08:49:37 +0000