Re: [RFC, v1 0/3] msi support for platform devices

Auger Eric
2020-11-12T18:40:28Z

Hi Vikas,

On 11/12/20 6:58 PM, Vikas Gupta wrote:
> This RFC adds support for MSI for platform devices.
> a) MSI(s) is/are added in addition to the normal interrupts.
> b) The vendor specific MSI configuration can be done using
> callbacks which is implemented as msi module.
> c) Adds a msi handling module for the Broadcom platform devices.
>
> Changes from:
> -------------
> 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|
> -------------------------------------------------------
I have not taken time yet to look at your series, but to me you should have
|IRQ-0|IRQ-1|....|IRQ-n|MSI|MSIX
then for setting a given MSIX (i) you would select the MSIx index and
then set start=i count=1.
to me individual MSIs are encoded in the subindex and not in the index.
The index just selects the "type" of interrupt.

For PCI you just have:
VFIO_PCI_INTX_IRQ_INDEX,
VFIO_PCI_MSI_IRQ_INDEX, -> MSI index and then you play with
start/count
VFIO_PCI_MSIX_IRQ_INDEX,
VFIO_PCI_ERR_IRQ_INDEX,
VFIO_PCI_REQ_IRQ_INDEX,

(include/uapi/linux/vfio.h)

Thanks

Eric
> 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: add Broadcom msi module
>
> drivers/vfio/platform/Kconfig | 1 +
> drivers/vfio/platform/Makefile | 1 +
> drivers/vfio/platform/msi/Kconfig | 9 +
> drivers/vfio/platform/msi/Makefile | 2 +
> .../vfio/platform/msi/vfio_platform_bcmplt.c | 74 ++++++
> drivers/vfio/platform/vfio_platform_common.c | 86 ++++++-
> drivers/vfio/platform/vfio_platform_irq.c | 238 +++++++++++++++++-
> drivers/vfio/platform/vfio_platform_private.h | 23 ++
> 8 files changed, 419 insertions(+), 15 deletions(-)
> create mode 100644 drivers/vfio/platform/msi/Kconfig
> create mode 100644 drivers/vfio/platform/msi/Makefile
> create mode 100644 drivers/vfio/platform/msi/vfio_platform_bcmplt.c
>