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| author |  Juergen Gross <jgross@suse.com>
| 2023-05-02 14:09:29 +0200 |
|---|---|---|
| committer |  Borislav Petkov (AMD) <bp@alien8.de>
| 2023-06-01 15:04:33 +0200 |
| commit | 973df1942068c0cc72244ce7dce5e5aeca03ad5f (patch) | |
| tree | 3fc6230c4acde5b2c7ede986d865766d2a765b1f | |
| parent | x86/mtrr: Use new cache_map in mtrr_type_lookup() (diff) | |
| download | linux-973df1942068c0cc72244ce7dce5e5aeca03ad5f.tar.gz linux-973df1942068c0cc72244ce7dce5e5aeca03ad5f.tar.bz2 linux-973df1942068c0cc72244ce7dce5e5aeca03ad5f.zip | |
x86/mtrr: Don't let mtrr_type_lookup() return MTRR_TYPE_INVALID
mtrr_type_lookup() should always return a valid memory type. In case
there is no information available, it should return the default UC.
This will remove the last case where mtrr_type_lookup() can return
MTRR_TYPE_INVALID, so adjust the comment in include/uapi/asm/mtrr.h.
Note that removing the MTRR_TYPE_INVALID #define from that header
could break user code, so it has to stay.
At the same time the mtrr_type_lookup() stub for the !CONFIG_MTRR
case should set uniform to 1, as if the memory range would be
covered by no MTRR at all.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
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/20230502120931.20719-15-jgross@suse.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
| -rw-r--r-- | arch/x86/include/asm/mtrr.h | 7 | ||||
| -rw-r--r-- | arch/x86/include/uapi/asm/mtrr.h | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/mtrr/generic.c | 4 |
3 files changed, 10 insertions, 7 deletions
diff --git a/arch/x86/include/asm/mtrr.h b/arch/x86/include/asm/mtrr.h index 1bae790a553a..5a758ee24bf7 100644 --- a/arch/x86/include/asm/mtrr.h +++ b/arch/x86/include/asm/mtrr.h @@ -86,9 +86,12 @@ static inline void mtrr_overwrite_state(struct mtrr_var_range *var, static inline u8 mtrr_type_lookup(u64 addr, u64 end, u8 *uniform) { /* - * Return no-MTRRs: + * Return the default MTRR type, without any known other types in + * that range. */ - return MTRR_TYPE_INVALID; + *uniform = 1; + + return MTRR_TYPE_UNCACHABLE; } #define mtrr_save_fixed_ranges(arg) do {} while (0) #define mtrr_save_state() do {} while (0) diff --git a/arch/x86/include/uapi/asm/mtrr.h b/arch/x86/include/uapi/asm/mtrr.h index ab194c831625..3a8a8eb8ac3a 100644 --- a/arch/x86/include/uapi/asm/mtrr.h +++ b/arch/x86/include/uapi/asm/mtrr.h @@ -107,9 +107,9 @@ typedef __u8 mtrr_type; #define MTRR_NUM_TYPES 7 /* - * Invalid MTRR memory type. mtrr_type_lookup() returns this value when - * MTRRs are disabled. Note, this value is allocated from the reserved - * values (0x7-0xff) of the MTRR memory types. + * Invalid MTRR memory type. No longer used outside of MTRR code. + * Note, this value is allocated from the reserved values (0x7-0xff) of + * the MTRR memory types. */ #define MTRR_TYPE_INVALID 0xff diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c index 4443e71084b8..f6b426d8be4f 100644 --- a/arch/x86/kernel/cpu/mtrr/generic.c +++ b/arch/x86/kernel/cpu/mtrr/generic.c @@ -508,13 +508,13 @@ u8 mtrr_type_lookup(u64 start, u64 end, u8 *uniform) if (!mtrr_state_set) { /* Uniformity is unknown. */ *uniform = 0; - return MTRR_TYPE_INVALID; + return MTRR_TYPE_UNCACHABLE; } *uniform = 1; if (!(mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED)) - return MTRR_TYPE_INVALID; + return MTRR_TYPE_UNCACHABLE; for (i = 0; i < cache_map_n && start < end; i++) { /* Region after current map entry? -> continue with next one. */ |