Re: [PATCH v4 23/39] x86/resctrl: Allow an architecture to disable pseudo lock

From: Reinette Chatre
Date: Wed Aug 14 2024 - 00:02:52 EST


Hi James,

On 8/2/24 10:28 AM, James Morse wrote:
Pseudo-lock relies on knowledge of the micro-architecture to disable
prefetchers etc.

On arm64 these controls are typically secure only, meaning linux can't
access them. Arm's cache-lockdown feature works in a very different
way. Resctrl's pseudo-lock isn't going to be used on arm64 platforms.

Add a Kconfig symbol that can be selected by the architecture. This
enables or disables building of the pseudo_lock.c file, and replaces
the functions with stubs. An additional IS_ENABLED() check is needed
in rdtgroup_mode_write() so that attempting to enable pseudo-lock
reports an "Unknown or unsupported mode" to user-space via the
last_cmd file.

"last_cmd file" -> "last_cmd_status file"

Reinette