Re: [PATCH v6 05/14] iommufd: Add IOMMUFD_OBJ_VEVENTQ and IOMMUFD_CMD_VEVENTQ_ALLOC

On Tue, Feb 18, 2025 at 09:47:50AM -0800, Nicolin Chen wrote:

I think we can do: if (!list_empty(list)) { struct iommufd_vevent *next;

next = list_first_entry(list, struct iommufd_vevent, node);
if (next == &veventq->overflow) {
	/* Make a copy of the overflow node for copy_to_user */
	vevent = kzalloc(sizeof(*vevent), GFP_ATOMIC);
	if (!vevent)
		goto out_unlock;
}
list_del(&next->node);
if (vevent)
	memcpy(vevent, next, sizeof(*vevent));
else
	vevent = next;

}

That looks right

...

...

+int iommufd_veventq_alloc(struct iommufd_ucmd *ucmd) +{

• struct iommu_veventq_alloc *cmd = ucmd->cmd;
• struct iommufd_veventq *veventq;
• struct iommufd_viommu *viommu;
• int fdno;
• int rc;
• if (cmd->flags || cmd->type == IOMMU_VEVENTQ_TYPE_DEFAULT)

• return -EOPNOTSUPP;
  

• if (!cmd->veventq_depth)

• return -EINVAL;
  

Check __reserved for 0 too

Kevin is suggesting a 32-bit flag field, so I think we can drop the __reserved in that case.

Those are different structs?

Jason