[tip: x86/mtrr] x86/mtrr: Add mtrr=debug command line option

tip-bot2 for Juergen Gross
2023-06-05T14:09:10Z

The following commit has been merged into the x86/mtrr branch of tip:

Commit-ID: a4316603534cf7f4dcd9f9f1ed170257b987cca9
Gitweb: https://git.kernel.org/tip/a4316603534cf7f4dcd9f9f1ed170257b987cca9
Author: Juergen Gross <jgross@suse.com>
AuthorDate: Tue, 02 May 2023 14:09:27 +02:00
Committer: Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Thu, 01 Jun 2023 15:04:33 +02:00

x86/mtrr: Add mtrr=debug command line option

Add a new command line option "mtrr=debug" for getting debug output
after building the new cache mode map. The output will include MTRR
register values and the resulting map.

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20230502120931.20719-13-jgross@suse.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
---
Documentation/admin-guide/kernel-parameters.txt | 4 +-
arch/x86/kernel/cpu/mtrr/generic.c | 64 +++++++++++-----
2 files changed, 49 insertions(+), 19 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 9e5bab2..44a87ad 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3423,6 +3423,10 @@
[HW] Make the MicroTouch USB driver use raw coordinates
('y', default) or cooked coordinates ('n')

+ mtrr=debug [X86]
+ Enable printing debug information related to MTRR
+ registers at boot time.
+
mtrr_chunk_size=nn[KMG] [X86]
used for mtrr cleanup. It is largest continuous chunk
that could hold holes aka. UC entries.
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index e0db6fc..852031e 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -41,6 +41,23 @@ struct cache_map {
u64 fixed:1;
};

+static bool mtrr_debug;
+
+static int __init mtrr_param_setup(char *str)
+{
+ int rc = 0;
+
+ if (!str)
+ return -EINVAL;
+ if (!strcmp(str, "debug"))
+ mtrr_debug = true;
+ else
+ rc = -EINVAL;
+
+ return rc;
+}
+early_param("mtrr", mtrr_param_setup);
+
/*
* CACHE_MAP_MAX is the maximum number of memory ranges in cache_map, where
* no 2 adjacent ranges have the same cache mode (those would be merged).
@@ -515,6 +532,14 @@ void __init mtrr_build_map(void)
pr_info("MTRR map: %u entries (%u fixed + %u variable; max %u), built from %u variable MTRRs\n",
cache_map_n, cache_map_fixed, cache_map_n - cache_map_fixed,
get_cache_map_size(), num_var_ranges + (mtrr_tom2 != 0));
+
+ if (mtrr_debug) {
+ for (i = 0; i < cache_map_n; i++) {
+ pr_info("%3u: %016llx-%016llx %s\n", i,
+ cache_map[i].start, cache_map[i].end - 1,
+ mtrr_attrib_to_str(cache_map[i].type));
+ }
+ }
}

/* Copy the cache_map from __initdata memory to dynamically allocated one. */
@@ -721,8 +746,8 @@ static void __init print_fixed_last(void)
if (!last_fixed_end)
return;

- pr_debug(" %05X-%05X %s\n", last_fixed_start,
- last_fixed_end - 1, mtrr_attrib_to_str(last_fixed_type));
+ pr_info(" %05X-%05X %s\n", last_fixed_start,
+ last_fixed_end - 1, mtrr_attrib_to_str(last_fixed_type));

last_fixed_end = 0;
}
@@ -760,10 +785,10 @@ static void __init print_mtrr_state(void)
unsigned int i;
int high_width;

- pr_debug("MTRR default type: %s\n",
- mtrr_attrib_to_str(mtrr_state.def_type));
+ pr_info("MTRR default type: %s\n",
+ mtrr_attrib_to_str(mtrr_state.def_type));
if (mtrr_state.have_fixed) {
- pr_debug("MTRR fixed ranges %sabled:\n",
+ pr_info("MTRR fixed ranges %sabled:\n",
((mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED) &&
(mtrr_state.enabled & MTRR_STATE_MTRR_FIXED_ENABLED)) ?
"en" : "dis");
@@ -778,27 +803,27 @@ static void __init print_mtrr_state(void)
/* tail */
print_fixed_last();
}
- pr_debug("MTRR variable ranges %sabled:\n",
- mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED ? "en" : "dis");
+ pr_info("MTRR variable ranges %sabled:\n",
+ mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED ? "en" : "dis");
high_width = (boot_cpu_data.x86_phys_bits - (32 - PAGE_SHIFT) + 3) / 4;

for (i = 0; i < num_var_ranges; ++i) {
if (mtrr_state.var_ranges[i].mask_lo & MTRR_PHYSMASK_V)
- pr_debug(" %u base %0*X%05X000 mask %0*X%05X000 %s\n",
- i,
- high_width,
- mtrr_state.var_ranges[i].base_hi,
- mtrr_state.var_ranges[i].base_lo >> 12,
- high_width,
- mtrr_state.var_ranges[i].mask_hi,
- mtrr_state.var_ranges[i].mask_lo >> 12,
- mtrr_attrib_to_str(mtrr_state.var_ranges[i].base_lo &
+ pr_info(" %u base %0*X%05X000 mask %0*X%05X000 %s\n",
+ i,
+ high_width,
+ mtrr_state.var_ranges[i].base_hi,
+ mtrr_state.var_ranges[i].base_lo >> 12,
+ high_width,
+ mtrr_state.var_ranges[i].mask_hi,
+ mtrr_state.var_ranges[i].mask_lo >> 12,
+ mtrr_attrib_to_str(mtrr_state.var_ranges[i].base_lo &
MTRR_PHYSBASE_TYPE));
else
- pr_debug(" %u disabled\n", i);
+ pr_info(" %u disabled\n", i);
}
if (mtrr_tom2)
- pr_debug("TOM2: %016llx aka %lldM\n", mtrr_tom2, mtrr_tom2>>20);
+ pr_info("TOM2: %016llx aka %lldM\n", mtrr_tom2, mtrr_tom2>>20);
}

/* Grab all of the MTRR state for this CPU into *state */
@@ -833,7 +858,8 @@ bool __init get_mtrr_state(void)
mtrr_tom2 &= 0xffffff800000ULL;
}

- print_mtrr_state();
+ if (mtrr_debug)
+ print_mtrr_state();

mtrr_state_set = 1;