Apertures

It allows a user to query what devices are available. But it's impossible to tell which is which without looking into topology info.

Topology can be found in KFD sysfs.

You might also get some more info about a device using the debugger api - device_snapshot functionality.

Be aware devices can be removed at runtime and in such cases these values become obsolete.

Scratch memory is unique per work item. LDS memory is unique per work group.

GET_PROCESS_APERTURES

	AMDKFD_IOR(0x06, struct kfd_ioctl_get_process_apertures_args)

Outputs

struct {
    __u64 lds_base;		/* from KFD */
	__u64 lds_limit;		/* from KFD */
	__u64 scratch_base;		/* from KFD */
	__u64 scratch_limit;		/* from KFD */
	__u64 gpuvm_base;		/* from KFD */
	__u64 gpuvm_limit;		/* from KFD */
	__u32 gpu_id;		/* from KFD */
} nodes[7];
__u32 num_of_nodes;

GET_PROCESS_APERTURES_NEW

	AMDKFD_IOWR(0x14, struct kfd_ioctl_get_process_apertures_new_args)

Just like GET_PROCESS_APERTURES except there is no limit to the number of nodes.