[PATCH v1 1/5] iommu/arm-smmu-v3-iommufd: Reject unsupported bits in invalidation commands

[Nicolin Chen]

On Fri, Jul 03, 2026 at 06:20:37AM +0000, Tian, Kevin wrote:
> > From: Nicolin Chen <nicolinc at nvidia.com>
> > +	case CMDQ_OP_ATC_INV:
> > +		/*
> > +		 * Exclude the Global bit: it makes the SMMU ignore the SID
> > and
> > +		 * invalidate the ATC of every device, not just the guest's.
> > +		 */
> 
> I suppose the Global bit in vcmdq is guaranteed by HW to be contained within
> the vcmdq, then the SMMU will convert it into multiple INV cmds sent to
> devices associated with the vcmdq?

Actually, this piece is wrong. I double-checked the spec, the
Global bit isn't about SID but SSID (should be provided too).
So, the Global bit should be allowed. I need to fix it..

Similarly for VCMDQ, it is allowed. HW only validates whether
the given SID/BDF is programmed into the VINTF or not.

Thanks (for the question)!
Nicolin