Commit-ID: 9b3aca620883fc06636737c82a4d024b22182281 Gitweb: http://git.kernel.org/tip/9b3aca620883fc06636737c82a4d024b22182281 Author: Toshi Kani <toshi.kani@xxxxxx> AuthorDate: Tue, 26 May 2015 10:28:06 +0200 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Wed, 27 May 2015 14:40:56 +0200 x86/mm/mtrr: Fix MTRR state checks in mtrr_type_lookup() 'mtrr_state.enabled' contains the FE (fixed MTRRs enabled) and E (MTRRs enabled) flags in MSR_MTRRdefType. Intel SDM, section 11.11.2.1, defines these flags as follows: - All MTRRs are disabled when the E flag is clear. The FE flag has no affect when the E flag is clear. - The default type is enabled when the E flag is set. - MTRR variable ranges are enabled when the E flag is set. - MTRR fixed ranges are enabled when both E and FE flags are set. MTRR state checks in __mtrr_type_lookup() do not match with SDM. Hence, this patch makes the following changes: - The current code detects MTRRs disabled when both E and FE flags are clear in mtrr_state.enabled. Fix to detect MTRRs disabled when the E flag is clear. - The current code does not check if the FE bit is set in mtrr_state.enabled when looking at the fixed entries. Fix to check the FE flag. - The current code returns the default type when the E flag is clear in mtrr_state.enabled. However, the default type is UC when the E flag is clear. Remove the code as this case is handled as MTRR disabled with the 1st change. In addition, this patch defines the E and FE flags in mtrr_state.enabled as follows. - FE flag: MTRR_STATE_MTRR_FIXED_ENABLED - E flag: MTRR_STATE_MTRR_ENABLED print_mtrr_state() and x86_get_mtrr_mem_range() are also updated accordingly. Signed-off-by: Toshi Kani <toshi.kani@xxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Brian Gerst <brgerst@xxxxxxxxx> Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx> Cc: Elliott@xxxxxx Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Luis R. Rodriguez <mcgrof@xxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: dave.hansen@xxxxxxxxx Cc: linux-mm <linux-mm@xxxxxxxxx> Cc: pebolle@xxxxxxxxxx Link: http://lkml.kernel.org/r/1431714237-880-4-git-send-email-toshi.kani@xxxxxx Link: http://lkml.kernel.org/r/1432628901-18044-4-git-send-email-bp@xxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/include/asm/mtrr.h | 4 ++++ arch/x86/kernel/cpu/mtrr/cleanup.c | 3 ++- arch/x86/kernel/cpu/mtrr/generic.c | 15 ++++++++------- 3 files changed, 14 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/mtrr.h b/arch/x86/include/asm/mtrr.h index f768f62..ef92794 100644 --- a/arch/x86/include/asm/mtrr.h +++ b/arch/x86/include/asm/mtrr.h @@ -127,4 +127,8 @@ struct mtrr_gentry32 { _IOW(MTRR_IOCTL_BASE, 9, struct mtrr_sentry32) #endif /* CONFIG_COMPAT */ +/* Bit fields for enabled in struct mtrr_state_type */ +#define MTRR_STATE_MTRR_FIXED_ENABLED 0x01 +#define MTRR_STATE_MTRR_ENABLED 0x02 + #endif /* _ASM_X86_MTRR_H */ diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c index 5f90b85..70d7c93 100644 --- a/arch/x86/kernel/cpu/mtrr/cleanup.c +++ b/arch/x86/kernel/cpu/mtrr/cleanup.c @@ -98,7 +98,8 @@ x86_get_mtrr_mem_range(struct range *range, int nr_range, continue; base = range_state[i].base_pfn; if (base < (1<<(20-PAGE_SHIFT)) && mtrr_state.have_fixed && - (mtrr_state.enabled & 1)) { + (mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED) && + (mtrr_state.enabled & MTRR_STATE_MTRR_FIXED_ENABLED)) { /* Var MTRR contains UC entry below 1M? Skip it: */ printk(BIOS_BUG_MSG, i); if (base + size <= (1<<(20-PAGE_SHIFT))) diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c index e202d26..b0599db 100644 --- a/arch/x86/kernel/cpu/mtrr/generic.c +++ b/arch/x86/kernel/cpu/mtrr/generic.c @@ -119,14 +119,16 @@ static u8 __mtrr_type_lookup(u64 start, u64 end, u64 *partial_end, int *repeat) if (!mtrr_state_set) return 0xFF; - if (!mtrr_state.enabled) + if (!(mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED)) return 0xFF; /* Make end inclusive end, instead of exclusive */ end--; /* Look in fixed ranges. Just return the type as per start */ - if (mtrr_state.have_fixed && (start < 0x100000)) { + if ((start < 0x100000) && + (mtrr_state.have_fixed) && + (mtrr_state.enabled & MTRR_STATE_MTRR_FIXED_ENABLED)) { int idx; if (start < 0x80000) { @@ -149,9 +151,6 @@ static u8 __mtrr_type_lookup(u64 start, u64 end, u64 *partial_end, int *repeat) * Look of multiple ranges matching this address and pick type * as per MTRR precedence */ - if (!(mtrr_state.enabled & 2)) - return mtrr_state.def_type; - prev_match = 0xFF; for (i = 0; i < num_var_ranges; ++i) { unsigned short start_state, end_state, inclusive; @@ -355,7 +354,9 @@ static void __init print_mtrr_state(void) mtrr_attrib_to_str(mtrr_state.def_type)); if (mtrr_state.have_fixed) { pr_debug("MTRR fixed ranges %sabled:\n", - mtrr_state.enabled & 1 ? "en" : "dis"); + ((mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED) && + (mtrr_state.enabled & MTRR_STATE_MTRR_FIXED_ENABLED)) ? + "en" : "dis"); print_fixed(0x00000, 0x10000, mtrr_state.fixed_ranges + 0); for (i = 0; i < 2; ++i) print_fixed(0x80000 + i * 0x20000, 0x04000, @@ -368,7 +369,7 @@ static void __init print_mtrr_state(void) print_fixed_last(); } pr_debug("MTRR variable ranges %sabled:\n", - mtrr_state.enabled & 2 ? "en" : "dis"); + mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED ? "en" : "dis"); high_width = (__ffs64(size_or_mask) - (32 - PAGE_SHIFT) + 3) / 4; for (i = 0; i < num_var_ranges; ++i) { -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>