On Thu, May 15, 2025 at 03:56:29PM -0300, Jason Gunthorpe wrote:
On Thu, May 15, 2025 at 11:52:05AM -0700, Nicolin Chen wrote:
On Thu, May 15, 2025 at 02:17:06PM -0300, Jason Gunthorpe wrote:
On Thu, May 08, 2025 at 08:02:39PM -0700, Nicolin Chen wrote:
Should the first call return out_data_type=CMDQV while returning the arm_smmu_v3 hw_info data? Otherwise, VMM wouldn't know what to set in the input sub_data_type of the 2nd ioctl?
No, either set a flag in the smmu_v3 hw_info, as you were doing here, or just have the vmm probe it. Given the VMM is likely to be told to run in vCMDQ mode on the command line try-and-fail doesn't sound so bad.
And I guess we don't need a "sub type" just a "requested type" where 0 means return the best one and non-zero means return a specific one or fail with EOPNOTSUPP.
OK. I think this would work: hw_info (req_type=0) => out_data_type=SMMU_V3, flags=HAS_CMDQV hw_info (req_type=CMDQV) => out_data_type=CMDQV, flags=0
Or, would it be simpler by having a sub_data_uptr: hw_info => out_data_type=SMMU_V3, sub_data_type=CMDQV, data_uptr=iommu_hw_info_arm_smmuv3, sub_data_uptr=iommu_hw_info_tegra241_cmdqv ?
Thanks Nicolin