[$] The misc control group
Control groups (cgroups) are meant to limit access to a shared resource among
processes in the system. One such resource is the values used to specify
an encrypted-memory region for a virtual machine, such as the address-space
identifiers (ASIDs) used by the AMD Secure
Encrypted Virtualization (SEV) feature. Vipin Sharma set
out to add a
control group for these ASIDs back in September; based on the feedback,
though, he expanded the idea into a controller to track and limit any countable resource.
The patch set
became the controller
for the misc control group and has been merged for Linux 5.13.