x86: mtrr cleanup for converting continuous to discrete layout, v8
some BIOS like to use continus MTRR layout, and X driver can not add
WB entries for graphical cards when 4g or more RAM installed.
the patch will change MTRR to discrete.
mtrr_chunk_size= could be used to have smaller continuous block to hold holes.
default is 256m, could be set according to size of graphics card memory.
mtrr_gran_size= could be used to send smallest mtrr block to avoid run out of MTRRs
v2: fix -1 for UC checking
v3: default to disable, and need use enable_mtrr_cleanup to enable this feature
skip the var state change warning.
remove next_basek in range_to_mtrr()
v4: correct warning mask.
v5: CONFIG_MTRR_SANITIZER
v6: fix 1g, 2g, 512 aligment with extra hole
v7: gran_sizek to prevent running out of MTRRs.
v8: fix hole_basek caculation caused when removing next_basek
gran_sizek using when basek is 0.
need to apply
[PATCH] x86: fix trimming e820 with MTRR holes.
right after this one.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index fe361ae..97a1764 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1092,6 +1092,32 @@
See <file:Documentation/mtrr.txt> for more information.
+config MTRR_SANITIZER
+ def_bool y
+ prompt "MTRR cleanup support"
+ depends on MTRR
+ help
+ Convert MTRR layout from continuous to discrete, so some X driver
+ could add WB entries.
+
+ Say N here if you see bootup problems (boot crash, boot hang,
+ spontaneous reboots).
+
+ Could be disabled with disable_mtrr_cleanup. Also mtrr_chunk_size
+ could be used to send largest mtrr entry size for continuous block
+ to hold holes (aka. UC entries)
+
+ If unsure, say Y.
+
+config MTRR_SANITIZER_ENABLE_DEFAULT
+ def_bool y
+ prompt "Enable MTRR cleanup by default"
+ depends on MTRR_SANITIZER
+ help
+ Enable mtrr cleanup by default
+
+ If unsure, say Y.
+
config X86_PAT
bool
prompt "x86 PAT support"