[RFC PATCH 2/8] x86/resctrl: Add L2CAT quirk for Intel Panther Lake

[Tony Luck]

Intel CPUs enumerate Resource Director Technology (RDT) allocation
features in CPUID leaf 0x10 if the feature is symmetric across all CPUs
and in CPUID leaf 0x28 if the feature is asymmetric.

But the P-core on Panther Lake enumerates L2 cache allocation in leaf
0x10, even though the feature is asymmetric between P-core and E-core.

Use set_rdt_options() to disable the symmetric enumeration.

Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
---
 arch/x86/kernel/cpu/resctrl/core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 7951cfd20da4..709075ffc706 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -1128,6 +1128,9 @@ static __init void __check_quirks_intel(void)
 	case INTEL_BROADWELL_X:
 		intel_rdt_mbm_apply_quirk();
 		break;
+	case INTEL_PANTHERLAKE_L:
+		set_rdt_options("!l2cat");
+		break;
 	}
 }
 
-- 
2.56.0