Re: [PATCH v2 10/22] iommufd/viommmu: Add IOMMUFD_CMD_VCMDQ_ALLOC ioctl

Pranjal Shrivastava
2025-04-29T18:14:12Z

On Tue, Apr 29, 2025 at 08:28:01AM +0000, Pranjal Shrivastava wrote:
> On Mon, Apr 28, 2025 at 03:44:08PM -0700, Nicolin Chen wrote:
> > On Mon, Apr 28, 2025 at 09:34:05PM +0000, Pranjal Shrivastava wrote:
> > > On Fri, Apr 25, 2025 at 10:58:05PM -0700, Nicolin Chen wrote:
> [...]
> > > IIUC, one vintf can have multiple lvcmdqs and looking at the series
> > > it looks like the vcmdq_alloc allocates a single lvcmdq. Is the plan to
> > > dedicate one lvcmdq to per VM? Which means VMs can share a vintf?
> >
> > VINTF is a vSMMU instance per SMMU. Each VINTF can have multiple
> > LVCMDQs. Each vCMDQ is allocated per IOMMUFD_CMD_VCMDQ_ALLOC. In
> > other word, VM can issue multiple IOMMUFD_CMD_VCMDQ_ALLOC calls
> > for each VTINF/vSMMU.
> >
>
> Ack. I'm just wondering why would a single VM want more than one vCMDQ
> per vSMMU?
> [...]

I guess the only thing on this patch from me was to understand why
would a single VM want more than one vCMDQ per vSMMU? (Just curious to
know :) )

Apart from that,
Reviewed-by: Pranjal Shrivastava <praan@google.com>

>
> > Thanks
> > Nicolin
>

Thanks,
Praan