On Fri, May 09, 2025 at 05:06:33PM +0000, Jiaqing Zhao wrote:
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
Next question: this is CC:stable, meaning it'll go to Linus now.
What exactly is it fixing?
Because the patch in Fixes: is from 2007. :-\