Create VM_MEMATTR_DEVICE on all architectures

[andrew]

Summary

This is intended to be used with memory mapped IO, e.g. from
bus_space_map with no flags, or pmap_mapdev.

Use this new memory type in the map request configured by
resource_init_map_request, and in pciconf.

[kib]

sys/amd64/include/vm.h

46

Why only for kernel?

Also, the recent change to pci_user.c can be simplified after your introduction of VM_MEMATTR_DEVICE, look at line 1129.

[andrew]

sys/amd64/include/vm.h

46

It would break the switch statement in usr.bin/vm/vmstat.c if we don't limit to just the kernel as it will have the same value twice.

[kib]

sys/amd64/include/vm.h

46

Then perhaps define MD name VM_MEMATTR_DEVMAP, present on all arches. It would be _UNCACHEABLE on x86, DEVICE on arm. pci_user.c would use _DEVMAP

[andrew]

sys/amd64/include/vm.h

46

We could also replace the switch statement with if else, e.g. D29703

[andrew]

• Remove _KERNEL checks
• Only use VM_MEMATTR_DEVICE in pciconf