linux.git/drivers/dma/idxd/cdev.c, branch v6.6

dmaengine: idxd: Fix passing freed memory in idxd_cdev_open()

2023-05-17T06:45:09+00:00

Smatch warns:
	drivers/dma/idxd/cdev.c:327:
		idxd_cdev_open() warn: 'sva' was already freed.

When idxd_wq_set_pasid() fails, the current code unbinds sva and then
goes to 'failed_set_pasid' where iommu_sva_unbind_device is called
again causing the above warning.
[ device_user_pasid_enabled(idxd) is still true when calling
failed_set_pasid ]

Fix this by removing additional unbind when idxd_wq_set_pasid() fails

Fixes: b022f59725f0 ("dmaengine: idxd: add idxd_copy_cr() to copy user completion record during page fault handling")
Signed-off-by: Harshit Mogalapalli 
Acked-by: Fenghua Yu 
Acked-by: Dave Jiang 
Link: https://lore.kernel.org/r/20230509060716.2830630-1-harshit.m.mogalapalli@oracle.com
Signed-off-by: Vinod Koul

dmaengine: idxd: add pid to exported sysfs attribute for opened file

2023-04-12T17:48:46+00:00

Provide the pid of the application for the opened file. This allows the
monitor daemon to easily correlate which app opened the file and easily
kill the app by pid if that is desired action.

Tested-by: Tony Zhu 
Signed-off-by: Dave Jiang 
Co-developed-by: Fenghua Yu 
Signed-off-by: Fenghua Yu 
Link: https://lore.kernel.org/r/20230407203143.2189681-16-fenghua.yu@intel.com
Signed-off-by: Vinod Koul

dmaengine: idxd: expose fault counters to sysfs

2023-04-12T17:48:46+00:00

Expose cr_faults and cr_fault_failures counters to the user space. This
allows a user app to keep track of how many fault the application is
causing with the completion record (CR) and also the number of failures
of the CR writeback. Having a high number of cr_fault_failures is bad as
the app is submitting descriptors with the CR addresses that are bad. User
monitoring daemon may want to consider killing the application as it may be
malicious and attempting to flood the device event log.

Tested-by: Tony Zhu 
Signed-off-by: Dave Jiang 
Co-developed-by: Fenghua Yu 
Signed-off-by: Fenghua Yu 
Link: https://lore.kernel.org/r/20230407203143.2189681-15-fenghua.yu@intel.com
Signed-off-by: Vinod Koul

dmaengine: idxd: add a device to represent the file opened

2023-04-12T17:48:45+00:00

Embed a struct device for the user file context in order to export sysfs
attributes related with the opened file. Tie the lifetime of the file
context to the device. The sysfs entry will be added under the char device.

Tested-by: Tony Zhu 
Signed-off-by: Dave Jiang 
Co-developed-by: Fenghua Yu 
Signed-off-by: Fenghua Yu 
Link: https://lore.kernel.org/r/20230407203143.2189681-14-fenghua.yu@intel.com
Signed-off-by: Vinod Koul

dmaengine: idxd: add per file user counters for completion record faults

2023-04-12T17:48:45+00:00

Add counters per opened file for the char device in order to keep track how
many completion record faults occurred and how many of those faults failed
the writeback by the driver after attempt to fault in the page. The
counters are managed by xarray that associates the PASID with
struct idxd_user_context.

Tested-by: Tony Zhu 
Signed-off-by: Dave Jiang 
Co-developed-by: Fenghua Yu 
Signed-off-by: Fenghua Yu 
Link: https://lore.kernel.org/r/20230407203143.2189681-13-fenghua.yu@intel.com
Signed-off-by: Vinod Koul

dmaengine: idxd: process user page faults for completion record

2023-04-12T17:48:45+00:00

DSA supports page fault handling through PRS. However, the DMA engine
that's processing the descriptor is blocked until the PRS response is
received. Other workqueues sharing the engine are also blocked.
Page fault handing by the driver with PRS disabled can be used to
mitigate the stalling.

With PRS disabled while ATS remain enabled, DSA handles page faults on
a completion record by reporting an event in the event log. In this
instance, the descriptor is completed and the event log contains the
completion record address and the contents of the completion record. Add
support to the event log handling code to fault in the completion record
and copy the content of the completion record to user memory.

A bitmap is introduced to keep track of discarded event log entries. When
the user process initiates ->release() of the char device, it no longer is
interested in any remaining event log entries tied to the relevant wq and
PASID. The driver will mark the event log entry index in the bitmap. Upon
encountering the entries during processing, the event log handler will just
clear the bitmap bit and skip the entry rather than attempt to process the
event log entry.

Tested-by: Tony Zhu 
Signed-off-by: Dave Jiang 
Co-developed-by: Fenghua Yu 
Signed-off-by: Fenghua Yu 
Link: https://lore.kernel.org/r/20230407203143.2189681-10-fenghua.yu@intel.com
Signed-off-by: Vinod Koul

dmaengine: idxd: add idxd_copy_cr() to copy user completion record during page fault handling

2023-04-12T17:48:45+00:00

Define idxd_copy_cr() to copy completion record to fault address in
user address that is found by work queue (wq) and PASID.

It will be used to write the user's completion record that the hardware
device is not able to write due to user completion record page fault.

An xarray is added to associate the PASID and mm with the
struct idxd_user_context so mm can be found by PASID and wq.

It is called when handling the completion record fault in a kernel thread
context. Switch to the mm using kthread_use_vm() and copy the
completion record to the mm via copy_to_user(). Once the copy is
completed, switch back to the current mm using kthread_unuse_mm().

Suggested-by: Christoph Hellwig 
Suggested-by: Jason Gunthorpe 
Suggested-by: Tony Luck 
Tested-by: Tony Zhu 
Signed-off-by: Fenghua Yu 
Reviewed-by: Dave Jiang 
Link: https://lore.kernel.org/r/20230407203143.2189681-9-fenghua.yu@intel.com
Signed-off-by: Vinod Koul

dmaengine: idxd: add per DSA wq workqueue for processing cr faults

2023-04-12T17:48:45+00:00

Add a workqueue for user submitted completion record fault processing.
The workqueue creation and destruction lifetime will be tied to the user
sub-driver since it will only be used when the wq is a user type.

Tested-by: Tony Zhu 
Signed-off-by: Dave Jiang 
Co-developed-by: Fenghua Yu 
Signed-off-by: Fenghua Yu 
Link: https://lore.kernel.org/r/20230407203143.2189681-7-fenghua.yu@intel.com
Signed-off-by: Vinod Koul

mm: replace vma->vm_flags direct modifications with modifier calls

2023-02-10T00:51:39+00:00

Replace direct modifications to vma->vm_flags with calls to modifier
functions to be able to track flag changes and to keep vma locking
correctness.

[akpm@linux-foundation.org: fix drivers/misc/open-dice.c, per Hyeonggon Yoo]
Link: https://lkml.kernel.org/r/20230126193752.297968-5-surenb@google.com
Signed-off-by: Suren Baghdasaryan 
Acked-by: Michal Hocko 
Acked-by: Mel Gorman 
Acked-by: Mike Rapoport (IBM) 
Acked-by: Sebastian Reichel 
Reviewed-by: Liam R. Howlett 
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Andy Lutomirski 
Cc: Arjun Roy 
Cc: Axel Rasmussen 
Cc: David Hildenbrand 
Cc: David Howells 
Cc: Davidlohr Bueso 
Cc: David Rientjes 
Cc: Eric Dumazet 
Cc: Greg Thelen 
Cc: Hugh Dickins 
Cc: Ingo Molnar 
Cc: Jann Horn 
Cc: Joel Fernandes 
Cc: Johannes Weiner 
Cc: Kent Overstreet 
Cc: Laurent Dufour 
Cc: Lorenzo Stoakes 
Cc: Matthew Wilcox 
Cc: Minchan Kim 
Cc: Paul E. McKenney 
Cc: Peter Oskolkov 
Cc: Peter Xu 
Cc: Peter Zijlstra 
Cc: Punit Agrawal 
Cc: Sebastian Andrzej Siewior 
Cc: Shakeel Butt 
Cc: Soheil Hassas Yeganeh 
Cc: Song Liu 
Cc: Vlastimil Babka 
Cc: Will Deacon 
Signed-off-by: Andrew Morton

Merge tag 'v6.1-rc7' into iommufd.git for-next

2022-12-02T16:04:39+00:00

Resolve conflicts in drivers/vfio/vfio_main.c by using the iommfd version.
The rc fix was done a different way when iommufd patches reworked this
code.

Signed-off-by: Jason Gunthorpe