Re: [PATCH 2/3] x86: add wrapper functions for mtrr functions handling also pat

On Fri, Jul 15, 2022 at 4:25 PM Juergen Gross jgross@suse.com wrote:

There are several MTRR functions which also do PAT handling. In order to support PAT handling without MTRR in the future, add some wrappers for those functions.

Cc: stable@vger.kernel.org # 5.17 Fixes: bdd8b6c98239 ("drm/i915: replace X86_FEATURE_PAT with pat_enabled()") Signed-off-by: Juergen Gross jgross@suse.com

Do I understand correctly that this particular patch doesn't change the behavior?

If so, it would be good to mention that in the changelog.

---

arch/x86/include/asm/mtrr.h | 2 -- arch/x86/include/asm/processor.h | 7 +++++ arch/x86/kernel/cpu/common.c | 44 +++++++++++++++++++++++++++++++- arch/x86/kernel/cpu/mtrr/mtrr.c | 25 +++--------------- arch/x86/kernel/setup.c | 5 +--- arch/x86/kernel/smpboot.c | 8 +++--- arch/x86/power/cpu.c | 2 +- 7 files changed, 59 insertions(+), 34 deletions(-)

diff --git a/arch/x86/include/asm/mtrr.h b/arch/x86/include/asm/mtrr.h index 12a16caed395..900083ac9f60 100644 --- a/arch/x86/include/asm/mtrr.h +++ b/arch/x86/include/asm/mtrr.h @@ -43,7 +43,6 @@ extern int mtrr_del(int reg, unsigned long base, unsigned long size); extern int mtrr_del_page(int reg, unsigned long base, unsigned long size); extern void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi); extern void mtrr_ap_init(void); -extern void set_mtrr_aps_delayed_init(void); extern void mtrr_aps_init(void); extern void mtrr_bp_restore(void); extern int mtrr_trim_uncached_memory(unsigned long end_pfn); @@ -86,7 +85,6 @@ static inline void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi) { } #define mtrr_ap_init() do {} while (0) -#define set_mtrr_aps_delayed_init() do {} while (0) #define mtrr_aps_init() do {} while (0) #define mtrr_bp_restore() do {} while (0) #define mtrr_disable() do {} while (0) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 5c934b922450..e2140204fb7e 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -865,7 +865,14 @@ bool arch_is_platform_page(u64 paddr); #define arch_is_platform_page arch_is_platform_page #endif

+extern bool cache_aps_delayed_init;

void cache_disable(void); void cache_enable(void); +void cache_bp_init(void); +void cache_ap_init(void); +void cache_set_aps_delayed_init(void); +void cache_aps_init(void); +void cache_bp_restore(void);

#endif /* _ASM_X86_PROCESSOR_H */ diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index e43322f8a4ef..0a1bd14f7966 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1929,7 +1929,7 @@ void identify_secondary_cpu(struct cpuinfo_x86 *c) #ifdef CONFIG_X86_32 enable_sep_cpu(); #endif

•   mtrr_ap_init();
  

•   cache_ap_init();
    validate_apic_and_package_id(c);
    x86_spec_ctrl_setup_ap();
    update_srbds_msr();
  

@@ -2403,3 +2403,45 @@ void cache_enable(void) __releases(cache_disable_lock)

    raw_spin_unlock(&cache_disable_lock);

}

+void __init cache_bp_init(void) +{

•   if (IS_ENABLED(CONFIG_MTRR))
  

•           mtrr_bp_init();
  

•   else
  

•           pat_disable("PAT support disabled because CONFIG_MTRR is disabled in the kernel.");
  

+}

+void cache_ap_init(void) +{

•   if (cache_aps_delayed_init)
  

•           return;
  

•   mtrr_ap_init();
  

+}

+bool cache_aps_delayed_init;

+void cache_set_aps_delayed_init(void) +{

•   cache_aps_delayed_init = true;
  

+}

+void cache_aps_init(void) +{

•   /*
  

•    * Check if someone has requested the delay of AP cache initialization,
  

•    * by doing cache_set_aps_delayed_init(), prior to this point. If not,
  

•    * then we are done.
  

•    */
  

•   if (!cache_aps_delayed_init)
  

•           return;
  

•   mtrr_aps_init();
  

•   cache_aps_delayed_init = false;
  

+}

+void cache_bp_restore(void) +{

•   mtrr_bp_restore();
  

+} diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c index 2746cac9d8a9..c1593cfae641 100644 --- a/arch/x86/kernel/cpu/mtrr/mtrr.c +++ b/arch/x86/kernel/cpu/mtrr/mtrr.c @@ -69,7 +69,6 @@ unsigned int mtrr_usage_table[MTRR_MAX_VAR_RANGES]; static DEFINE_MUTEX(mtrr_mutex);

u64 size_or_mask, size_and_mask; -static bool mtrr_aps_delayed_init;

static const struct mtrr_ops *mtrr_ops[X86_VENDOR_NUM] __ro_after_init;

@@ -176,7 +175,8 @@ static int mtrr_rendezvous_handler(void *info) if (data->smp_reg != ~0U) { mtrr_if->set(data->smp_reg, data->smp_base, data->smp_size, data->smp_type);

•   } else if (mtrr_aps_delayed_init || !cpu_online(smp_processor_id())) {
  

•   } else if ((use_intel() && cache_aps_delayed_init) ||
  

•              !cpu_online(smp_processor_id())) {
            mtrr_if->set_all();
    }
    return 0;
  

@@ -789,7 +789,7 @@ void mtrr_ap_init(void) if (!mtrr_enabled()) return;

•   if (!use_intel() || mtrr_aps_delayed_init)
  

•   if (!use_intel())
            return;
  
    /*
  

@@ -823,16 +823,6 @@ void mtrr_save_state(void) smp_call_function_single(first_cpu, mtrr_save_fixed_ranges, NULL, 1); }

-void set_mtrr_aps_delayed_init(void) -{

•   if (!mtrr_enabled())
  

•           return;
  

•   if (!use_intel())
  

•           return;
  

•   mtrr_aps_delayed_init = true;
  

-}

/*

• Delayed MTRR initialization for all AP's

*/ @@ -841,16 +831,7 @@ void mtrr_aps_init(void) if (!use_intel() || !mtrr_enabled()) return;

•   /*
  

•    * Check if someone has requested the delay of AP MTRR initialization,
  

•    * by doing set_mtrr_aps_delayed_init(), prior to this point. If not,
  

•    * then we are done.
  

•    */
  

•   if (!mtrr_aps_delayed_init)
  

•           return;
  

•   set_mtrr(~0U, 0, 0, 0);
  

•   mtrr_aps_delayed_init = false;
  

}

void mtrr_bp_restore(void) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index bd6c6fd373ae..27d61f73c68a 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1001,10 +1001,7 @@ void __init setup_arch(char **cmdline_p) max_pfn = e820__end_of_ram_pfn();

    /* update e820 for memory not covered by WB MTRRs */

•   if (IS_ENABLED(CONFIG_MTRR))
  

•           mtrr_bp_init();
  

•   else
  

•           pat_disable("PAT support disabled because CONFIG_MTRR is disabled in the kernel.");
  

•   cache_bp_init();
  
    if (mtrr_trim_uncached_memory(max_pfn))
            max_pfn = e820__end_of_ram_pfn();
  

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 5e7f9532a10d..535d73a47062 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1432,7 +1432,7 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)

    uv_system_init();

•   set_mtrr_aps_delayed_init();
  

•   cache_set_aps_delayed_init();
  
    smp_quirk_init_udelay();
  
  

@@ -1443,12 +1443,12 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)

void arch_thaw_secondary_cpus_begin(void) {

•   set_mtrr_aps_delayed_init();
  

•   cache_set_aps_delayed_init();
  

}

void arch_thaw_secondary_cpus_end(void) {

•   mtrr_aps_init();
  

•   cache_aps_init();
  

}

/* @@ -1491,7 +1491,7 @@ void __init native_smp_cpus_done(unsigned int max_cpus)

    nmi_selftest();
    impress_friends();

•   mtrr_aps_init();
  

•   cache_aps_init();
  

}

static int __initdata setup_possible_cpus = -1; diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c index bb176c72891c..21e014715322 100644 --- a/arch/x86/power/cpu.c +++ b/arch/x86/power/cpu.c @@ -261,7 +261,7 @@ static void notrace __restore_processor_state(struct saved_context *ctxt) do_fpu_end(); tsc_verify_tsc_adjust(true); x86_platform.restore_sched_clock_state();

•   mtrr_bp_restore();
  

•   cache_bp_restore();
    perf_restore_debug_store();
  
    c = &cpu_data(smp_processor_id());
  

-- 2.35.3