[RFC v4 0/3] msi support for platform devices

Vikas Gupta
2021-01-29T17:25:34Z

[-- Attachment #1: Type: text/plain, Size: 2484 bytes --]

This RFC adds support for MSI for platform devices.
MSI block is added as an ext irq along with the existing
wired interrupt implementation. The patchset exports two
caps for MSI and related data to configure MSI source device.

Changes from:
-------------
v3 to v4:
1) Removed the 'cap' for exporting MSI info to userspace and
restored into vedor specific module.
2) Enable GENERIC_MSI_IRQ_DOMAIN in Kconfig.
3) Removed the vendor specific, Broadcom, 'msi' module and
integrated the MSI relates ops into the 'reset' module for
MSI support.

v2 to v3:
1) Restored the vendor specific module to get max number
of MSIs supported and .count value initialized.
2) Comments from Eric addressed.

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@redhat.com/

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 (3):
vfio/platform: add support for msi
vfio/platform: change cleanup order
vfio: platform: reset: add msi support

drivers/vfio/platform/Kconfig | 1 +
.../platform/reset/vfio_platform_bcmflexrm.c | 72 ++++-
drivers/vfio/platform/vfio_platform_common.c | 97 +++++--
drivers/vfio/platform/vfio_platform_irq.c | 253 ++++++++++++++++--
drivers/vfio/platform/vfio_platform_private.h | 29 ++
include/uapi/linux/vfio.h | 24 ++
6 files changed, 444 insertions(+), 32 deletions(-)

--
2.17.1