diff mbox series

[v11,09/13] x86/process: Clear hardware feedback history for AMD processors

Message ID 20250609200518.3616080-10-superm1@kernel.org
State New
Headers show
Series Add support for AMD hardware feedback interface | expand

Commit Message

Mario Limonciello June 9, 2025, 8:05 p.m. UTC 
From: Perry Yuan <perry.yuan@amd.com>

Incorporate a mechanism within the context switching code to reset
the hardware history for AMD processors. Specifically, when a task
is switched in, the class ID was read and reset the hardware workload
classification history of CPU firmware and then it start to trigger
workload classification for the next running thread.

Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v8:
 * Only for 64 bit
---
 arch/x86/kernel/process_64.c | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 8d6cf25127aab..f386928c472db 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -707,6 +707,10 @@  __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 	/* Load the Intel cache allocation PQR MSR. */
 	resctrl_arch_sched_in(next_p);
 
+	/* Reset hw history on AMD CPUs */
+	if (cpu_feature_enabled(X86_FEATURE_AMD_WORKLOAD_CLASS))
+		wrmsrl(MSR_AMD_WORKLOAD_HRST, 0x1);
+
 	return prev_p;
 }