From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:43340 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932404AbcHNQAn (ORCPT ); Sun, 14 Aug 2016 12:00:43 -0400 Subject: Patch "x86/pat: Document the PAT initialization sequence" has been added to the 4.4-stable tree To: toshi.kani@hpe.com, akpm@linux-foundation.org, bp@alien8.de, bp@suse.de, brgerst@gmail.com, dvlasenk@redhat.com, gregkh@linuxfoundation.org, hpa@zytor.com, jgross@suse.com, luto@amacapital.net, mcgrof@suse.com, mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de, torvalds@linux-foundation.org, toshi.kani@hp.com Cc: , From: Date: Sun, 14 Aug 2016 18:00:18 +0200 Message-ID: <14711904183620@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled x86/pat: Document the PAT initialization sequence to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-pat-document-the-pat-initialization-sequence.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From b6350c21cfe8aa9d65e189509a23c0ea4b8362c2 Mon Sep 17 00:00:00 2001 From: Toshi Kani Date: Wed, 23 Mar 2016 15:42:03 -0600 Subject: x86/pat: Document the PAT initialization sequence From: Toshi Kani commit b6350c21cfe8aa9d65e189509a23c0ea4b8362c2 upstream. Update PAT documentation to describe how PAT is initialized under various configurations. Signed-off-by: Toshi Kani Reviewed-by: Thomas Gleixner Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Juergen Gross Cc: Linus Torvalds Cc: Luis R. Rodriguez Cc: Peter Zijlstra Cc: Toshi Kani Cc: elliott@hpe.com Cc: konrad.wilk@oracle.com Cc: paul.gortmaker@windriver.com Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1458769323-24491-8-git-send-email-toshi.kani@hpe.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- Documentation/x86/pat.txt | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) --- a/Documentation/x86/pat.txt +++ b/Documentation/x86/pat.txt @@ -196,3 +196,35 @@ Another, more verbose way of getting PAT "debugpat" boot parameter. With this parameter, various debug messages are printed to dmesg log. +PAT Initialization +------------------ + +The following table describes how PAT is initialized under various +configurations. The PAT MSR must be updated by Linux in order to support WC +and WT attributes. Otherwise, the PAT MSR has the value programmed in it +by the firmware. Note, Xen enables WC attribute in the PAT MSR for guests. + + MTRR PAT Call Sequence PAT State PAT MSR + ========================================================= + E E MTRR -> PAT init Enabled OS + E D MTRR -> PAT init Disabled - + D E MTRR -> PAT disable Disabled BIOS + D D MTRR -> PAT disable Disabled - + - np/E PAT -> PAT disable Disabled BIOS + - np/D PAT -> PAT disable Disabled - + E !P/E MTRR -> PAT init Disabled BIOS + D !P/E MTRR -> PAT disable Disabled BIOS + !M !P/E MTRR stub -> PAT disable Disabled BIOS + + Legend + ------------------------------------------------ + E Feature enabled in CPU + D Feature disabled/unsupported in CPU + np "nopat" boot option specified + !P CONFIG_X86_PAT option unset + !M CONFIG_MTRR option unset + Enabled PAT state set to enabled + Disabled PAT state set to disabled + OS PAT initializes PAT MSR with OS setting + BIOS PAT keeps PAT MSR with BIOS setting + Patches currently in stable-queue which might be from toshi.kani@hpe.com are queue-4.4/x86-mm-pat-replace-cpu_has_pat-with-boot_cpu_has.patch queue-4.4/x86-mtrr-fix-xorg-crashes-in-qemu-sessions.patch queue-4.4/x86-mm-pat-add-support-of-non-default-pat-msr-setting.patch queue-4.4/x86-xen-pat-remove-pat-table-init-code-from-xen.patch queue-4.4/x86-mtrr-fix-pat-init-handling-when-mtrr-is-disabled.patch queue-4.4/x86-mm-pat-add-pat_disable-interface.patch queue-4.4/x86-mm-pat-fix-bug_on-in-mmap_mem-on-qemu-i386.patch queue-4.4/x86-pat-document-the-pat-initialization-sequence.patch