Messages in this thread | | | Date | Mon, 1 Apr 2024 14:19:35 -0700 | From | Andi Kleen <> | Subject | [PING] Re: [PATCH v3] x86/mtrr: Check if fixed MTRRs exist before saving them |
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On Wed, Feb 28, 2024 at 04:19:52PM -0800, Andi Kleen wrote: > MTRRs have a obsolete fixed variant for fine grained > caching control of the 640K-1MB region. This fixed variant has a > separate capability bit in the MTRR capability MSR. The MTRR code > checks this capability bit before trying to access the fixed MTRR MSRs, > except in one place. This patch fixes this place to also > check the capability. > > Otherwise there will be a WARN_ON when the respective MSRS don't exist. > > Fixes: 2b1f6278d77c ("[PATCH] x86: Save the MTRRs of the BSP before booting an AP") > Signed-off-by: Andi Kleen <ak@linux.intel.com>
Ping!
> > --- > > v2: Add Fixes tag and expand description. > v3: Expand description > --- > arch/x86/kernel/cpu/mtrr/mtrr.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c > index 767bf1c71aad..2a2fc14955cd 100644 > --- a/arch/x86/kernel/cpu/mtrr/mtrr.c > +++ b/arch/x86/kernel/cpu/mtrr/mtrr.c > @@ -609,7 +609,7 @@ void mtrr_save_state(void) > { > int first_cpu; > > - if (!mtrr_enabled()) > + if (!mtrr_enabled() || !mtrr_state.have_fixed) > return; > > first_cpu = cpumask_first(cpu_online_mask); > -- > 2.43.0 >
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