[PATCH v6 08/18] x86/resctrl: Register RESCTRL_GLOBAL_ENABLE_PER_CPU when PLZA is available

[Babu Moger]

PLZA (Privilege Level Zero Association) provides the global per-CPU kernel
mode, RESCTRL_GLOBAL_ENABLE_PER_CPU, allowing kernel work to use allocation
and monitoring associations that differ from user tasks.

Add x86 support for this kernel mode and make it available through the
resctrl kernel-mode infrastructure.

Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v6: Use RESCTRL_GLOBAL_ENABLE_PER_CPU.
    Rewrite changelog (not a bugfix).

v5: Update the patch to adapt new data structure and resctrl_set_kmode_support()
    changes.

v4: New patch to set the supported features during arch init.
---
 arch/x86/kernel/cpu/resctrl/core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 4ca8bedeb995..fc59d66f77de 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -1021,6 +1021,10 @@ static __init bool get_rdt_resources(void)
 	rdt_alloc_capable = get_rdt_alloc_resources();
 	rdt_mon_capable = get_rdt_mon_resources();
 
+	if (rdt_cpu_has(X86_FEATURE_PLZA) &&
+	    (rdt_alloc_capable || rdt_mon_capable))
+		resctrl_set_kmode_support(RESCTRL_GLOBAL_ENABLE_PER_CPU);
+
 	return (rdt_mon_capable || rdt_alloc_capable);
 }
 
-- 
2.43.0