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| author | Juergen Gross <jgross@suse.com> | 2015-01-12 06:15:45 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2015-01-20 14:33:45 +0100 |
| commit | 9d34cfdf47963905d792ae9c000efa522739abe4 (patch) | |
| tree | cc408b47f8f71877647dcf4ab6252f64e96fc1fd /arch | |
| parent | 4a0d3107d6b19125f21172c2b7d95f9c30ecaf6f (diff) | |
| download | linux-9d34cfdf47963905d792ae9c000efa522739abe4.tar.gz linux-9d34cfdf47963905d792ae9c000efa522739abe4.tar.bz2 linux-9d34cfdf47963905d792ae9c000efa522739abe4.zip | |
x86: Don't rely on VMWare emulating PAT MSR correctly
VMWare seems not to emulate the PAT MSR correctly: reaeding
MSR_IA32_CR_PAT returns 0 even after writing another value to it.
Commit bd809af16e3ab triggers this VMWare bug when the kernel is
booted as a VMWare guest.
Detect this bug and don't use the read value if it is 0.
Fixes: bd809af16e3ab "x86: Enable PAT to use cache mode translation tables"
Reported-and-tested-by: Jongman Heo <jongman.heo@samsung.com>
Acked-by: Alok N Kataria <akataria@vmware.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Link: http://lkml.kernel.org/r/1421039745-14335-1-git-send-email-jgross@suse.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/mm/pat.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index edf299c8ff6c..7ac68698406c 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -234,8 +234,13 @@ void pat_init(void) PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC); /* Boot CPU check */ - if (!boot_pat_state) + if (!boot_pat_state) { rdmsrl(MSR_IA32_CR_PAT, boot_pat_state); + if (!boot_pat_state) { + pat_disable("PAT read returns always zero, disabled."); + return; + } + } wrmsrl(MSR_IA32_CR_PAT, pat); |