[RFC, v2 0/1] msi support for platform devices

[Vikas Gupta]

This RFC adds support for MSI for platform devices.
MSI block is added as an ext irq along with the existing
wired interrupt implementation.

Changes from:
-------------
 v1 to v2:
	1) IRQ allocation has been implemented as below:
	       ----------------------------
	       |IRQ-0|IRQ-1|....|IRQ-n|MSI|
       	       ----------------------------
		MSI block has msi contexts and its implemneted
		as ext irq.

	2) Removed vendor specific module for msi handling so
	   previously patch2 and patch3 are not required.

	3) MSI related data is exported to userspace using 'caps'.
	 Please note VFIO_IRQ_INFO_CAP_TYPE in include/uapi/linux/vfio.h implementation
	is taken from the Eric`s patch
        https://patchwork.kernel.org/project/kvm/patch/20201116110030.32335-8-eric.auger@xxxxxxxxxx/


 v0 to v1:
   i)  Removed MSI device flag VFIO_DEVICE_FLAGS_MSI.
   ii) Add MSI(s) at the end of the irq list of platform IRQs.
       MSI(s) with first entry of MSI block has count and flag
       information.
       IRQ list: Allocation for IRQs + MSIs are allocated as below
       Example: if there are 'n' IRQs and 'k' MSIs
       -------------------------------------------------------
       |IRQ-0|IRQ-1|....|IRQ-n|MSI-0|MSI-1|MSI-2|......|MSI-k|
       -------------------------------------------------------
       MSI-0 will have count=k set and flags set accordingly.

Vikas Gupta (1):
  vfio/platform: add support for msi

 drivers/vfio/platform/vfio_platform_common.c  |  99 ++++++-
 drivers/vfio/platform/vfio_platform_irq.c     | 260 +++++++++++++++++-
 drivers/vfio/platform/vfio_platform_private.h |  16 ++
 include/uapi/linux/vfio.h                     |  43 +++
 4 files changed, 401 insertions(+), 17 deletions(-)

-- 
2.17.1

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