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

Jason,

On 5/7/2025 6:01 PM, Jason Gunthorpe wrote:

On Wed, May 07, 2025 at 01:11:43PM +0530, Vasant Hegde wrote:

...

• 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.

Ok

...

 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

This sounds like modifying the vqueue? Or maybe on the viommu?

IMO its VIOMMU as it informs HW to trigger interrupt or not.

...

• 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.

This sounds like a modify on the VIOMMU object?

Again in my view its VIOMMU object as it tells HW what to do when it finishes completion wait command.

-Vasant