On 1/15/21 6:32 PM, Vipin Sharma wrote:
> Documentation of Encryption IDs controller. This new controller is used
> to track and limit usage of hardware memory encryption capabilities on
> the CPUs.
>
> Signed-off-by: Vipin Sharma <vipinsh@xxxxxxxxxx>
> Reviewed-by: David Rientjes <rientjes@xxxxxxxxxx>
> Reviewed-by: Dionna Glaze <dionnaglaze@xxxxxxxxxx>
> ---
> .../admin-guide/cgroup-v1/encryption_ids.rst | 1 +
> Documentation/admin-guide/cgroup-v2.rst | 78 ++++++++++++++++++-
> 2 files changed, 77 insertions(+), 2 deletions(-)
> create mode 100644 Documentation/admin-guide/cgroup-v1/encryption_ids.rst
>
> diff --git a/Documentation/admin-guide/cgroup-v1/encryption_ids.rst b/Documentation/admin-guide/cgroup-v1/encryption_ids.rst
> new file mode 100644
> index 000000000000..8e9e9311daeb
> --- /dev/null
> +++ b/Documentation/admin-guide/cgroup-v1/encryption_ids.rst
> @@ -0,0 +1 @@
> +/Documentation/admin-guide/cgroup-v2.rst
> diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
> index 63521cd36ce5..72993571de2e 100644
> --- a/Documentation/admin-guide/cgroup-v2.rst
> +++ b/Documentation/admin-guide/cgroup-v2.rst
> @@ -63,8 +63,11 @@ v1 is available under :ref:`Documentation/admin-guide/cgroup-v1/index.rst <cgrou
> 5-7-1. RDMA Interface Files
> 5-8. HugeTLB
> 5.8-1. HugeTLB Interface Files
> - 5-8. Misc
> - 5-8-1. perf_event
> + 5-9. Encryption IDs
> + 5.9-1 Encryption IDs Interface Files
> + 5.9-2 Migration and Ownership
> + 5-10. Misc
> + 5-10-1. perf_event
> 5-N. Non-normative information
> 5-N-1. CPU controller root cgroup process behaviour
> 5-N-2. IO controller root cgroup process behaviour
> @@ -2160,6 +2163,77 @@ HugeTLB Interface Files
> are local to the cgroup i.e. not hierarchical. The file modified event
> generated on this file reflects only the local events.
>
> +Encryption IDs
> +--------------
> +
> +There are multiple hardware memory encryption capabilities provided by the
> +hardware vendors, like Secure Encrypted Virtualization (SEV) and SEV Encrypted
> +State (SEV-ES) from AMD.
> +
> +These features are being used in encrypting virtual machines (VMs) and user
> +space programs. However, only a small number of keys/IDs can be used
> +simultaneously.
> +
> +This limited availability of these IDs requires system admin to optimize
admins
> +allocation, control, and track the usage of the resources in the cloud
> +infrastructure. This resource also needs to be protected from getting exhausted
> +by some malicious program and causing starvation for other programs.
> +
> +Encryption IDs controller provides capability to register the resource for
The Encryption IDs controller provides the capability to register the resource for
> +controlling and tracking through the cgroups.
through cgroups.
> +
> +Encryption IDs Interface Files
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +Each encryption ID type have their own interface files,
has its own
> +encids.[ID TYPE].{max, current, stat}, where "ID TYPE" can be sev and
or
> +sev-es.
> +
> + encids.[ID TYPE].stat
> + A read-only flat-keyed single value file. This file exists only in the
> + root cgroup.
> +
> + It shows the total number of encryption IDs available and currently in
> + use on the platform::
> + # cat encids.sev.stat
> + total 509
> + used 0
This is described above as a single-value file...
Is the max value a hardware limit or a software (flexible) limit?
> +
> + encids.[ID TYPE].max
> + A read-write file which exists on the non-root cgroups. File is used to
> + set maximum count of "[ID TYPE]" which can be used in the cgroup.
> +
> + Limit can be set to max by::
> + # echo max > encids.sev.max
> +
> + Limit can be set by::
> + # echo 100 > encids.sev.max
> +
> + This file shows the max limit of the encryption ID in the cgroup::
> + # cat encids.sev.max
> + max
> +
> + OR::
> + # cat encids.sev.max
> + 100
> +
> + Limits can be set more than the "total" capacity value in the
> + encids.[ID TYPE].stat file, however, the controller ensures
> + that the usage never exceeds the "total" and the max limit.
> +
> + encids.[ID TYPE].current
> + A read-only single value file which exists on non-root cgroups.
> +
> + Shows the total number of encrypted IDs being used in the cgroup.
> +
> +Migration and Ownership
> +~~~~~~~~~~~~~~~~~~~~~~~
> +
> +An encryption ID is charged to the cgroup in which it is used first, and
> +stays charged to that cgroup until that ID is freed. Migrating a process
> +to a different cgroup do not move the charge to the destination cgroup
does
> +where the process has moved.
> +
> Misc
> ----
>
>
--
~Randy
You can't do anything without having to do something else first.
-- Belefant's Law
