When suspending, save_processor_state() calls mtrr_save_fixed_ranges() to save fixed-range MTRRs. On platforms without fixed-range MTRRs, accessing these MSRs will trigger unchecked MSR access error. Make sure fixed-range MTRRs are supported before access to prevent such error.

Since mtrr_state.have_fixed is only set when MTRRs are present and enabled, checking the CPU feature flag in mtrr_save_fixed_ranges() is unnecessary.

Fixes: 3ebad5905609 ("[PATCH] x86: Save and restore the fixed-range MTRRs of the BSP when suspending") Cc: stable@vger.kernel.org Signed-off-by: Jiaqing Zhao jiaqing.zhao@linux.intel.com --- v2: * Removed unnecessary boot_cpu_has(X86_FEATURE_MTRR) check. * Updated commit message. Link: https://lore.kernel.org/all/20250509085612.2236222-2-jiaqing.zhao@linux.inte...

arch/x86/kernel/cpu/mtrr/generic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c index e2c6b471d230..8c18327eb10b 100644 --- a/arch/x86/kernel/cpu/mtrr/generic.c +++ b/arch/x86/kernel/cpu/mtrr/generic.c @@ -593,7 +593,7 @@ static void get_fixed_ranges(mtrr_type *frs)

void mtrr_save_fixed_ranges(void *info) { - if (boot_cpu_has(X86_FEATURE_MTRR)) + if (mtrr_state.have_fixed) get_fixed_ranges(mtrr_state.fixed_ranges); }