From 08fc1e7b31f8832e356ede8afae1ad1ff0d5a1fc Mon Sep 17 00:00:00 2001 From: Rong Zhang Date: Wed, 22 Jul 2026 02:13:43 +0800 Subject: [PATCH] cpufreq/amd-pstate: Prevent the driver from loading on unsupported hardware X86_FEATURE_HW_PSTATE indicates if the processor supports frequency scaling or not. Without it, the driver is unusable and thus will not load. This check also prevents the driver from loading in guests and thus not confuse users with misleading prints. Reviewed-by: Michael Kelley Tested-by: Michael Kelley Acked-by: Mario Limonciello (AMD) Reviewed-by: K Prateek Nayak Tested-by: K Prateek Nayak Acked-by: Borislav Petkov (AMD) Signed-off-by: Rong Zhang Link: https://lore.kernel.org/r/20260722-amd-pstate-vm-v4-1-d6607d9e9d9a@rong.moe Signed-off-by: Mario Limonciello --- drivers/cpufreq/amd-pstate.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index 3d72337a3336..3a6b4b224a66 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -2167,6 +2167,7 @@ static struct cpufreq_driver amd_pstate_epp_driver = { }; /* + * Processors without frequency scaling support can't do CPPC. * CPPC function is not supported for family ID 17H with model_ID ranging from 0x10 to 0x2F. * show the debug message that helps to check if the CPU has CPPC support for loading issue. */ @@ -2175,6 +2176,11 @@ static bool amd_cppc_supported(void) struct cpuinfo_x86 *c = &cpu_data(0); bool warn = false; + if (!cpu_feature_enabled(X86_FEATURE_HW_PSTATE)) { + pr_debug_once("frequency scaling is not supported by the processor\n"); + return false; + } + if ((boot_cpu_data.x86 == 0x17) && (boot_cpu_data.x86_model < 0x30)) { pr_debug_once("CPPC feature is not supported by the processor\n"); return false;