On Wed, Jul 02, 2025 at 12:14:28AM +0000, Pranjal Shrivastava wrote:
Thus, coming back to the two initial points:
- Issuing "non-invalidation" commands through .cache_invalidate could be confusing, I'm not asking to change the op name here, but if we plan to label it, let's label them as "Trapped commands" OR "non-accelerated" commands as you suggested.
VCMDQ only accelerates limited invalidation commands, not all of them: STE cache invalidation and CD cache invalidation commands still go down to that op.
- The "FIXME" confusion: The comment in arm_vsmmu_cache_invalidate mentions we'd like to "fix" the issuing of commands through the main cmdq and instead like to group by "type", if that "type" is the queue type (which I assume it is because IOMMU_TYPE has to be arm-smmu-v3),
I recall that FIXME is noted by Jason at that time. And it should be interpreted as "group by opcode", IIUIC.
The thing is that for a host kernel that enabled in-kernel VCMDQs, those trapped user commands can be just issued to the smmu->cmdq or a vcmdq (picked via the get_secondary_cmdq impl_op).
what do we plan to do differently there, given that the op is only for trapped commands *have* to go through the main CMDQ?
If we do something differently there, it could just do a one-time get_secondary_cmdq call to pick a in-kernel vcmdq over smmu->cmdq to fill in all the trapped commands.
And this is not related to this series at all.
Nicolin