Re: [PATCH v6 11/16] x86/mtrr: construct a memory map with cache modes

Borislav Petkov
2023-05-09T11:37:34Z

On Tue, May 02, 2023 at 02:09:26PM +0200, Juergen Gross wrote:
> @@ -841,6 +1137,10 @@ static void generic_set_mtrr(unsigned int reg, unsigned long base,
>
> cache_enable();
> local_irq_restore(flags);
> +
> + /* On the first CPU rebuild the cache mode memory map. */
> + if (smp_processor_id() == cpumask_first(cpu_online_mask))
> + rebuild_map();

I still don't like this. Anything against doing this instead?

---
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index 163dca53796c..e69c8c56897f 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -458,8 +458,11 @@ static void map_add_var(void)
* removals of registers, which are complicated to handle without rebuild of
* the map.
*/
-static void rebuild_map(void)
+void rebuild_map(void)
{
+ if (mtrr_if != &generic_mtrr_ops)
+ return;
+
cache_map_n = cache_map_fixed;

map_add_var();
@@ -1127,10 +1130,6 @@ static void generic_set_mtrr(unsigned int reg, unsigned long base,

cache_enable();
local_irq_restore(flags);
-
- /* On the first CPU rebuild the cache mode memory map. */
- if (smp_processor_id() == cpumask_first(cpu_online_mask))
- rebuild_map();
}

int generic_validate_add_page(unsigned long base, unsigned long size,
diff --git a/arch/x86/kernel/cpu/mtrr/legacy.c b/arch/x86/kernel/cpu/mtrr/legacy.c
index d25882fcf181..30a3d51d06e0 100644
--- a/arch/x86/kernel/cpu/mtrr/legacy.c
+++ b/arch/x86/kernel/cpu/mtrr/legacy.c
@@ -67,6 +67,7 @@ static void mtrr_restore(void)
mtrr_value[i].ltype);
}
}
+ rebuild_map();
}

static struct syscore_ops mtrr_syscore_ops = {
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c
index 5fb61bb97ab1..10608c7f9606 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.c
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.c
@@ -187,6 +187,8 @@ static void set_mtrr(unsigned int reg, unsigned long base, unsigned long size,
};

stop_machine_cpuslocked(mtrr_rendezvous_handler, &data, cpu_online_mask);
+
+ rebuild_map();
}

/**
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.h b/arch/x86/kernel/cpu/mtrr/mtrr.h
index 48ffd89cf3a6..286ce89ce7f1 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.h
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.h
@@ -79,3 +79,4 @@ extern const struct mtrr_ops centaur_mtrr_ops;

extern int changed_by_mtrr_cleanup;
extern int mtrr_cleanup(void);
+void rebuild_map(void);

--
Regards/Gruss,
Boris.