Re: [RFC PATCH v6 09/11] iommufd: Add the vdevice TSM request ioctl

[Jason Gunthorpe]

On Fri, Sep 18, 2026 at 11:09:29PM +1000, Alexey Kardashevskiy wrote:
> 
> 
> On 18/9/26 00:01, Aneesh Kumar K.V (Arm) wrote:
> > A VMM needs to forward guest-originated TSM commands to the TSM
> > implementation managing an assigned device. The IOMMUFD vdevice
> > identifies that device within its vIOMMU and provides the appropriate
> > dispatch point.
> > 
> > Add IOMMU_VDEVICE_TSM_REQ to send an opaque request to a vdevice and
> > optionally return a response. Define common operation and guest
> > architecture identifiers for CCA, SEV and TDX requests.
> 
> iommufd_viommu_provider_ops already knows what architecture it is,
> why bother with these identifiers? Thanks,

At the uAPI boundary we want something like a strace to be able to
dump and inspect the system call without having to inspect hidden
knowledge of what is inside the FD. That's a huge PITA.

So saything 'this is an x86 format request that uses this coding' is
the right thing.

Jason