X-Received: by 10.43.152.9 with SMTP id ku9mr19887975icc.8.1427236208691; Tue, 24 Mar 2015 15:30:08 -0700 (PDT) X-BeenThere: linux.kernel@googlegroups.com Received: by 10.182.221.169 with SMTP id qf9ls66754obc.55.gmail; Tue, 24 Mar 2015 15:30:03 -0700 (PDT) X-Received: by 10.182.245.169 with SMTP id xp9mr7849679obc.44.1427236203026; Tue, 24 Mar 2015 15:30:03 -0700 (PDT) MIME-Version: 1.0 Path: db6ni62418igc.0!nntp.google.com!border1.nntp.dca1.giganews.com!nntp.giganews.com!goblin3!goblin2!goblin.stu.neva.ru!aioe.org!bofh.it!news.nic.it!robomod From: Toshi Kani Newsgroups: linux.kernel Subject: [PATCH v4 4/7] mtrr, x86: Fix MTRR state checks in mtrr_type_lookup() Date: Tue, 24 Mar 2015 23:30:02 +0100 Message-ID: References: X-Original-To: ak...@linux-foundation.org, h...@zytor.com, tg...@linutronix.de, mi...@redhat.com X-Mailer: git-send-email 1.9.3 Sender: rob...@news.nic.it List-ID: X-Mailing-List: linux-...@vger.kernel.org Approved: rob...@news.nic.it Lines: 110 Organization: linux.* mail to news gateway X-Original-Cc: linu...@kvack.org, x...@kernel.org, linux-...@vger.kernel.org, dave....@intel.com, Ell...@hp.com, peb...@tiscali.nl, Toshi Kani X-Original-Date: Tue, 24 Mar 2015 16:08:38 -0600 X-Original-Message-ID: <1427234921-19737-5-git...@hp.com> X-Original-References: <1427234921-19737-1-git...@hp.com> X-Original-Sender: linux-ker...@vger.kernel.org Bytes: 5663 '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 into 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 also disabled when the E flag is clear. Fix to 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() is also updated accordingly. Signed-off-by: Toshi Kani --- arch/x86/include/uapi/asm/mtrr.h | 4 ++++ arch/x86/kernel/cpu/mtrr/generic.c | 15 ++++++++------- 2 files changed, 12 insertions(+), 7 deletions(-) diff --git a/arch/x86/include/uapi/asm/mtrr.h b/arch/x86/include/uapi/asm/mtrr.h index d0acb65..66ba88d 100644 --- a/arch/x86/include/uapi/asm/mtrr.h +++ b/arch/x86/include/uapi/asm/mtrr.h @@ -88,6 +88,10 @@ struct mtrr_state_type { mtrr_type def_type; }; +/* Bit fields for enabled in struct mtrr_state_type */ +#define MTRR_STATE_MTRR_FIXED_ENABLED 0x01 +#define MTRR_STATE_MTRR_ENABLED 0x02 + #define MTRRphysBase_MSR(reg) (0x200 + 2 * (reg)) #define MTRRphysMask_MSR(reg) (0x200 + 2 * (reg) + 1)