Re: MSI-X vector limits and reserving a virtio device ID

On Wed, May 27, 2026 at 07:53:11PM -0400, Demi Marie Obenour wrote:
> I'd like to reserve a virtio device ID for virtio vhost-guest,
> formally virtio vhost-user.  Would this be possible?

yes, follow the regular process for reserving IDs.

> Also, I'd like to know which systems have a small limit on the number
> of MSI-X vectors.  The vhost-guest device uses lots of MSI-X vectors.
> Typical implementations will use 256 * 3 + 7 = 775 of them!  That can,
> of course, be reduced by sharing vectors, but this is undesirable
> as it comes at a performance cost.

A single cpu x86 system?

> -- 
> Sincerely,
> Demi Marie Obenour (she/her/hers)