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

Auger Eric
2020-12-02T14:45:24Z

Hi Vikas,
On 11/24/20 5:16 PM, Vikas Gupta wrote:
> 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
it is implemented
> 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/
So do you mean that by exposing the vectors, now you do not need the msi
module anymore?

Thanks

Eric
>
>
> 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(-)
>