linux-stable.git/drivers/vfio/platform, branch linux-4.8.y

vfio: platform: check reset call return code during release

2016-07-19T16:54:45+00:00

Release call is ignoring the return code from reset call and can
potentially continue even though reset call failed.

If reset_required module parameter is set, this patch is going
to validate the return code and will cause stack dump with
WARN_ON and warn the user of failure.

Signed-off-by: Sinan Kaya 
Reviewed-by: Eric Auger 
Reviewed-by: Baptiste Reynal 
Signed-off-by: Alex Williamson

vfio: platform: check reset call return code during open

2016-07-19T16:54:45+00:00

Open call is ignoring the return code from reset call and can
potentially continue even though reset call failed.

If reset_required module parameter is set, this patch is going
to validate the return code and will abort open if reset fails.

Signed-off-by: Sinan Kaya 
Reviewed-by: Baptiste Reynal 
Reviewed-by: Eric Auger 
Signed-off-by: Alex Williamson

vfio, platform: make reset driver a requirement by default

2016-07-19T16:26:46+00:00

The code was allowing platform devices to be used without a supporting
VFIO reset driver. The hardware can be left in some inconsistent state
after a guest machine abort.

The reset driver will put the hardware back to safe state and disable
interrupts before returning the control back to the host machine.

Adding a new reset_required kernel module option to platform VFIO drivers.
The default value is true for the DT and ACPI based drivers.
The reset requirement value for AMBA drivers is set to false and is
unchangeable to maintain the existing functionality.

New requirements are:
1. A reset function needs to be implemented by the corresponding driver
via DT/ACPI.
2. The reset function needs to be discovered via DT/ACPI.

The probe of the driver will fail if any of the above conditions are
not satisfied.

Signed-off-by: Sinan Kaya 
Signed-off-by: Alex Williamson

vfio: platform: call _RST method when using ACPI

2016-07-19T16:26:44+00:00

The device tree code checks for the presence of a reset driver and calls
the of_reset function pointer by looking up the reset driver as a module.

ACPI defines _RST method to perform device level reset. After the _RST
method is executed, the OS can resume using the device. _RST method is
expected to stop DMA transfers and IRQs.

This patch introduces two functions as vfio_platform_acpi_has_reset and
vfio_platform_acpi_call_reset. The has reset method is used to declare
reset capability via the ioctl flag VFIO_DEVICE_FLAGS_RESET. The call
reset function is used to execute the _RST ACPI method.

Signed-off-by: Sinan Kaya 
Signed-off-by: Alex Williamson

vfio: platform: add extra debug info argument to call reset

2016-07-19T16:26:43+00:00

Getting ready to bring out extra debug information to the caller
so that more verbose information can be printed when an error is
observed.

Signed-off-by: Sinan Kaya 
Reviewed-by: Baptiste Reynal 
Signed-off-by: Alex Williamson

vfio: platform: add support for ACPI probe

2016-07-19T16:26:41+00:00

The code is using the compatible DT string to associate a reset driver
with the actual device itself. The compatible string does not exist on
ACPI based systems. HID is the unique identifier for a device driver
instead.

Signed-off-by: Sinan Kaya 
Signed-off-by: Alex Williamson

vfio: platform: determine reset capability

2016-07-19T16:26:40+00:00

Creating a new function to determine if this driver supports reset
function or not. This is an attempt to abstract device tree calls
from the rest of the code.

Signed-off-by: Sinan Kaya 
Reviewed-by: Eric Auger 
Reviewed-by: Baptiste Reynal 
Signed-off-by: Alex Williamson

vfio: platform: move reset call to a common function

2016-07-19T16:26:38+00:00

The reset call sequence seems to replicate itself multiple times
across the file. Grouping them together for maintenance reasons.

Signed-off-by: Sinan Kaya 
Reviewed-by: Eric Auger 
Reviewed-by: Baptiste Reynal 
Signed-off-by: Alex Williamson

vfio: platform: rename reset function

2016-07-19T16:26:36+00:00

Renaming the reset function to of_reset as it is only used
by the device tree based platforms.

Signed-off-by: Sinan Kaya 
Reviewed-by: Eric Auger 
Reviewed-by: Baptiste Reynal 
Signed-off-by: Alex Williamson

vfio: platform: support No-IOMMU mode

2016-06-23T15:37:17+00:00

The vfio No-IOMMU mode was supported by this
'commit 03a76b60f8ba2797 ("vfio: Include No-IOMMU mode")',
but it only support vfio-pci.

Using vfio_iommu_group_get/put, but not iommu_group_get/put,
the platform devices can be exposed to userspace with
CONFIG_VFIO_NOIOMMU and the "enable_unsafe_noiommu_mode"
option enabled.

From 'commit 03a76b60f8ba2797 ("vfio: Include No-IOMMU mode")',
"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."

Signed-off-by: Peng Fan 
Cc: Eric Auger 
Cc: Baptiste Reynal 
Cc: Alex Williamson 
Reviewed-by: Eric Auger 
Signed-off-by: Alex Williamson