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Groups > linux.kernel > #1363694
| From | Toshi Kani <toshi.kani@hpe.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v3 7/7] x86/pat: Document PAT initialization |
| Date | 2016-03-23 22:00 +0100 |
| Message-ID | <rfY2L-ua-29@gated-at.bofh.it> (permalink) |
| References | <rfXT4-qz-15@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Update PAT documentation to describe how PAT is initialized under various configurations. Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Cc: Borislav Petkov <bp@suse.de> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Juergen Gross <jgross@suse.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> --- Documentation/x86/pat.txt | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/Documentation/x86/pat.txt b/Documentation/x86/pat.txt index 54944c7..8ccc0fc 100644 --- a/Documentation/x86/pat.txt +++ b/Documentation/x86/pat.txt @@ -196,3 +196,35 @@ Another, more verbose way of getting PAT related debug messages is with "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. 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 enable + Disabled PAT state set to disable + OS PAT initializes PAT MSR with OS setting + BIOS PAT keeps PAT MSR with BIOS setting +
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[PATCH v3 0/7] Enhance PAT init to fix Xorg crashes Toshi Kani <toshi.kani@hpe.com> - 2016-03-23 21:50 +0100
[PATCH v3 1/7] x86/mm/pat: Add support of non-default PAT MSR setting Toshi Kani <toshi.kani@hpe.com> - 2016-03-23 21:50 +0100
[tip:x86/mm] x86/mm/pat: Add support of non-default PAT MSR setting tip-bot for Toshi Kani <tipbot@zytor.com> - 2016-03-29 12:40 +0200
[PATCH v3 5/7] x86/mtrr: Fix PAT init handling when MTRR is disabled Toshi Kani <toshi.kani@hpe.com> - 2016-03-23 22:00 +0100
[tip:x86/mm] x86/mtrr: Fix PAT init handling when MTRR is disabled tip-bot for Toshi Kani <tipbot@zytor.com> - 2016-03-29 12:50 +0200
[PATCH v3 6/7] x86/xen,pat: Remove PAT table init code from Xen Toshi Kani <toshi.kani@hpe.com> - 2016-03-23 22:00 +0100
[tip:x86/mm] x86/xen, pat: Remove PAT table init code from Xen tip-bot for Toshi Kani <tipbot@zytor.com> - 2016-03-29 12:50 +0200
[PATCH v3 3/7] x86/mm/pat: Replace cpu_has_pat with boot_cpu_has Toshi Kani <toshi.kani@hpe.com> - 2016-03-23 22:00 +0100
[tip:x86/mm] x86/mm/pat: Replace cpu_has_pat with boot_cpu_has() tip-bot for Toshi Kani <tipbot@zytor.com> - 2016-03-29 12:50 +0200
[PATCH v3 2/7] x86/mm/pat: Add pat_disable() interface Toshi Kani <toshi.kani@hpe.com> - 2016-03-23 22:00 +0100
[tip:x86/mm] x86/mm/pat: Add pat_disable() interface tip-bot for Toshi Kani <tipbot@zytor.com> - 2016-03-29 12:50 +0200
[PATCH v3 7/7] x86/pat: Document PAT initialization Toshi Kani <toshi.kani@hpe.com> - 2016-03-23 22:00 +0100
[tip:x86/mm] x86/pat: Document the PAT initialization sequence tip-bot for Toshi Kani <tipbot@zytor.com> - 2016-03-29 12:50 +0200
[PATCH v3 4/6] x86/mtrr: Fix Xorg crashes in Qemu sessions Toshi Kani <toshi.kani@hpe.com> - 2016-03-23 22:00 +0100
[tip:x86/mm] x86/mtrr: Fix Xorg crashes in Qemu sessions tip-bot for Toshi Kani <tipbot@zytor.com> - 2016-03-29 12:50 +0200
Re: [PATCH v3 0/7] Enhance PAT init to fix Xorg crashes Ingo Molnar <mingo@kernel.org> - 2016-03-29 12:40 +0200
Re: [PATCH v3 0/7] Enhance PAT init to fix Xorg crashes Toshi Kani <toshi.kani@hpe.com> - 2016-03-29 15:30 +0200
Re: [Xen-devel] [PATCH v3 0/7] Enhance PAT init to fix Xorg crashes Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-03-29 16:50 +0200
Re: [Xen-devel] [PATCH v3 0/7] Enhance PAT init to fix Xorg crashes Toshi Kani <toshi.kani@hpe.com> - 2016-03-29 17:00 +0200
Re: [Xen-devel] [PATCH v3 0/7] Enhance PAT init to fix Xorg crashes "Luis R. Rodriguez" <mcgrof@suse.com> - 2016-03-30 20:10 +0200
Re: [LKP] [Xen-devel] [PATCH v3 0/7] Enhance PAT init to fix Xorg crashes "Luis R. Rodriguez" <mcgrof@suse.com> - 2016-03-30 22:20 +0200
Re: [LKP] [Xen-devel] [PATCH v3 0/7] Enhance PAT init to fix Xorg crashes "Luis R. Rodriguez" <mcgrof@suse.com> - 2016-03-30 22:50 +0200
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