linux-stable.git/drivers/dma/idxd/cdev.c, branch linux-6.2.y

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

iommu: Remove SVM_FLAG_SUPERVISOR_MODE support

2022-11-03T14:47:45+00:00

The current kernel DMA with PASID support is based on the SVA with a flag
SVM_FLAG_SUPERVISOR_MODE. The IOMMU driver binds the kernel memory address
space to a PASID of the device. The device driver programs the device with
kernel virtual address (KVA) for DMA access. There have been security and
functional issues with this approach:

- The lack of IOTLB synchronization upon kernel page table updates.
  (vmalloc, module/BPF loading, CONFIG_DEBUG_PAGEALLOC etc.)
- Other than slight more protection, using kernel virtual address (KVA)
  has little advantage over physical address. There are also no use
  cases yet where DMA engines need kernel virtual addresses for in-kernel
  DMA.

This removes SVM_FLAG_SUPERVISOR_MODE support from the IOMMU interface.
The device drivers are suggested to handle kernel DMA with PASID through
the kernel DMA APIs.

The drvdata parameter in iommu_sva_bind_device() and all callbacks is not
needed anymore. Cleanup them as well.

Link: https://lore.kernel.org/linux-iommu/20210511194726.GP1002214@nvidia.com/
Signed-off-by: Jacob Pan 
Signed-off-by: Lu Baolu 
Reviewed-by: Jason Gunthorpe 
Reviewed-by: Jean-Philippe Brucker 
Reviewed-by: Kevin Tian 
Reviewed-by: Fenghua Yu 
Tested-by: Zhangfei Gao 
Tested-by: Tony Zhu 
Link: https://lore.kernel.org/r/20221031005917.45690-4-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel

dmaengine: idxd: Do not enable user type Work Queue without Shared Virtual Addressing

2022-10-19T13:32:10+00:00

When the idxd_user_drv driver is bound to a Work Queue (WQ) device
without IOMMU or with IOMMU Passthrough without Shared Virtual
Addressing (SVA), the application gains direct access to physical
memory via the device by programming physical address to a submitted
descriptor. This allows direct userspace read and write access to
arbitrary physical memory. This is inconsistent with the security
goals of a good kernel API.

Unlike vfio_pci driver, the IDXD char device driver does not provide any
ways to pin user pages and translate the address from user VA to IOVA or
PA without IOMMU SVA. Therefore the application has no way to instruct the
device to perform DMA function. This makes the char device not usable for
normal application usage.

Since user type WQ without SVA cannot be used for normal application usage
and presents the security issue, bind idxd_user_drv driver and enable user
type WQ only when SVA is enabled (i.e. user PASID is enabled).

Fixes: 448c3de8ac83 ("dmaengine: idxd: create user driver for wq 'device'")
Cc: stable@vger.kernel.org
Suggested-by: Arjan Van De Ven 
Signed-off-by: Fenghua Yu 
Reviewed-by: Dave Jiang 
Reviewed-by: Jerry Snitselaar 
Link: https://lore.kernel.org/r/20221014222541.3912195-1-fenghua.yu@intel.com
Signed-off-by: Vinod Koul

dmaengine: idxd: Separate user and kernel pasid enabling

2022-05-16T12:49:29+00:00

The idxd driver always gated the pasid enabling under a single knob and
this assumption is incorrect. The pasid used for kernel operation can be
independently toggled and has no dependency on the user pasid (and vice
versa). Split the two so they are independent "enabled" flags.

Signed-off-by: Dave Jiang 
Link: https://lore.kernel.org/r/165231431746.986466.5666862038354800551.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul

dmaengine: idxd: Fix the error handling path in idxd_cdev_register()

2022-05-16T11:28:32+00:00

If a call to alloc_chrdev_region() fails, the already allocated resources
are leaking.

Add the needed error handling path to fix the leak.

Fixes: 42d279f9137a ("dmaengine: idxd: add char driver to expose submission portal to userland")
Signed-off-by: Christophe JAILLET 
Acked-by: Dave Jiang 
Link: https://lore.kernel.org/r/1b5033dcc87b5f2a953c413f0306e883e6114542.1650521591.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Vinod Koul

dmaengine: idxd: refactor wq driver enable/disable operations

2022-04-22T07:24:20+00:00

Move the core driver operations from wq driver to the drv_enable_wq() and
drv_disable_wq() functions. The move should reduce the wq driver's
knowledge of the core driver operations and prevent code confusion for
future wq drivers.

Signed-off-by: Dave Jiang 
Link: https://lore.kernel.org/r/165047301643.3841827.11222723219862233060.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul

dmaengine: idxd: remove interrupt disable for dev_lock

2021-08-29T13:44:20+00:00

The spinlock is not being used in hard interrupt context. There is no need
to disable irq when acquiring the lock. The interrupt thread handler also
is not in bottom half context, therefore we can also remove disabling of
the bh. Convert all dev_lock acquisition to plain spin_lock() calls.

Reviewed-by: Dan Williams 
Signed-off-by: Dave Jiang 
Link: https://lore.kernel.org/r/162984026772.1939166.11504067782824765879.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul

dmanegine: idxd: add software command status

2021-07-28T12:26:55+00:00

Enabling device and wq returns standard errno and that does not provide
enough details to indicate what exactly failed. The hardware command status
is only 8bits. Expand the command status to 32bits and use the upper 16
bits to define software errors to provide more details on the exact
failure. Bit 31 will be used to indicate the error is software set as the
driver is using some of the spec defined hardware error as well.

Cc: Ramesh Thomas 
Signed-off-by: Dave Jiang 
Link: https://lore.kernel.org/r/162681373579.1968485.5891788397526827892.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul

dmaengine: idxd: move dsa_drv support to compatible mode

2021-07-21T04:39:16+00:00

The original architecture of /sys/bus/dsa invented a scheme whereby
a single entry in the list of bus drivers, /sys/bus/drivers/dsa,
handled all device types and internally routed them to different
different drivers. Those internal drivers were invisible to
userspace.

With the idxd driver transitioned to a proper bus device-driver model,
the legacy behavior needs to be preserved due to it being exposed to
user space via sysfs. Create a compat driver to provide the legacy
behavior for /sys/bus/dsa/drivers/dsa. This should satisfy user
tool accel-config v3.2 or ealier where this behavior is expected.
If the distro has a newer accel-config then the legacy mode does
not need to be enabled.

When the compat driver binds the device (i.e. dsa0) to the dsa driver,
it will be bound to the new idxd_drv. The wq device (i.e. wq0.0) will
be bound to either the dmaengine_drv or the user_drv. The dsa_drv
becomes a routing mechansim for the new drivers. It will not support
additional external drivers that are implemented later.

Reviewed-by: Dan Williams 
Signed-off-by: Dave Jiang 
Link: https://lore.kernel.org/r/162637468705.744545.4399080971745974435.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul

dmaengine: idxd: create user driver for wq 'device'

2021-07-21T04:39:16+00:00

The original architecture of /sys/bus/dsa invented a scheme whereby a
single entry in the list of bus drivers, /sys/bus/drivers/dsa, handled
all device types and internally routed them to different drivers.
Those internal drivers were invisible to userspace. Now, as
/sys/bus/dsa wants to grow support for alternate drivers for a given
device, for example vfio-mdev instead of kernel-internal-dmaengine, a
proper bus device-driver model is needed. The first step in that process
is separating the existing omnibus/implicit "dsa" driver into proper
individual drivers registered on /sys/bus/dsa. Establish the
idxd_user_drv driver that controls the enabling and disabling of the
wq and also register and unregister a char device to allow user space
to mmap the descriptor submission portal.

The cdev related bits are moved to the cdev driver probe/remove and out of
the drv_enabe/disable_wq() calls. These bits are exclusive to the cdev
operation and not part of the generic enable/disable of the wq device.

Reviewed-by: Dan Williams 
Signed-off-by: Dave Jiang 
Link: https://lore.kernel.org/r/162637467578.744545.10203997610072341376.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul