[PATCH v3 11/23] iommufd/viommu: Add IOMMUFD_CMD_VQUEUE_ALLOC ioctl

[Tian, Kevin]

> From: Vasant Hegde <vasant.hegde at amd.com>
> Sent: Wednesday, May 7, 2025 3:42 PM
> 
> Hi Jason,
> 
> 
> On 5/6/2025 5:31 PM, Jason Gunthorpe wrote:
> > Do you need a modify queue operation?
> 
> We have two types of operations. One that impacts the queue, other set of
> bits
> which doesn't operate on qeueue.
> 
> ex: Event log buffer
>   - We configure "MMIO Offset 0010h Event Log Base Address Register" with
> Base
> address and size
> 
>   -  MMIO Offset 0018h IOMMU Control Register
>      EventLogEn: Event log enable
>        * When guest sets this bit, qemu will trap and will send queue_alloc
>        * When guest disables this bit, qemu will trap and send vqueue_destroy
> 
>      This part is fine.
> 
>      EventIntEn: Event log interrupt enable
>        * When guest sets this bit, qemu will trap
>        * this needs to be communicated to Host so that we can program VF
> Control
> BAR and enable the interrupt
> 
>   - There is other bit "Completion wait interrupt enable"
>     This doesn't related to any buffer. Instead if we configure this for
> completion wait command it will generate interrupt.
> 
> I am asking how do we handle above two steps? Should it be part of queue
> IOCTL
> or may be some other IOCTL which just passes these info to HW driver?
> 

Probably IOMMUFD_CMD_OPTION can server the purpose?