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Re: runtime regression with "x86/mm/pat: Emulate PAT when it is disabled"

From Paul Gortmaker <paul.gortmaker@windriver.com>
Newsgroups linux.kernel
Subject Re: runtime regression with "x86/mm/pat: Emulate PAT when it is disabled"
Date 2016-03-10 15:50 +0100
Message-ID <rba4y-8hd-5@gated-at.bofh.it> (permalink)
References (5 earlier) <rac8q-y1-23@gated-at.bofh.it> <rac8q-y1-21@gated-at.bofh.it> <radeb-1go-43@gated-at.bofh.it> <radnT-1zk-89@gated-at.bofh.it> <rae0z-1QO-43@gated-at.bofh.it>
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[Re: runtime regression with "x86/mm/pat: Emulate PAT when it is disabled"] On 07/03/2016 (Mon 18:35) Toshi Kani wrote:

> On Mon, 2016-03-07 at 17:56 -0700, Toshi Kani wrote:

[...]

> And also an output of /proc/cpuinfo, please?

Here is the output of /proc/cpuinfo in the guest session, while
running on pentium dual core as host (no vmx):


processor	: 0
vendor_id	: GenuineIntel
cpu family	: 6
model		: 6
model name	: QEMU Virtual CPU version 2.5+
stepping	: 3
cpu MHz		: 2593.449
cache size	: 4096 KB
physical id	: 0
siblings	: 1
core id		: 0
cpu cores	: 1
apicid		: 0
initial apicid	: 0
fdiv_bug	: no
f00f_bug	: no
coma_bug	: no
fpu		: yes
fpu_exception	: yes
cpuid level	: 4
wp		: yes
flags		: fpu de pse tsc msr pae mce cx8 apic sep pge cmov mmx fxsr sse sse2 pni hypervisor
bugs		:
bogomips	: 5186.89
clflush size	: 32
cache_alignment	: 32
address sizes	: 36 bits physical, 32 bits virtual
power management:

Paul.
--

> 
> I think I know what's going on.  I noticed that you have the following
> message in your dmesg files.
> 
>  [    0.000000] MTRR: Disabled
> 
> MTRR is set to disabled when your CPU is Intel but does not support MTRR.
>  Perhaps, QEMU does not emulate MTRR?
> 
> pat_init() is not called when MTRR is disabled.  I think this dependency is
> wrong, and it needs to be fixed.
> 
> This issue has been there for a long time, and you have been running
> essentially as PAT disabled in the past.  The commit in question simply
> detected this issue.
> 
> Thanks,
> -Toshi

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Thread

Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Paul Gortmaker <paul.gortmaker@windriver.com> - 2016-03-04 19:40 +0100
  Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Toshi Kani <toshi.kani@hpe.com> - 2016-03-04 22:30 +0100
    Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Paul Gortmaker <paul.gortmaker@windriver.com> - 2016-03-07 01:40 +0100
      Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Toshi Kani <toshi.kani@hpe.com> - 2016-03-07 16:20 +0100
        Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Toshi Kani <toshi.kani@hpe.com> - 2016-03-07 23:50 +0100
          Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Paul Gortmaker <paul.gortmaker@windriver.com> - 2016-03-08 01:00 +0100
            Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Toshi Kani <toshi.kani@hpe.com> - 2016-03-08 01:10 +0100
              Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Toshi Kani <toshi.kani@hpe.com> - 2016-03-08 01:50 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Paul Gortmaker <paul.gortmaker@windriver.com> - 2016-03-08 04:30 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Toshi Kani <toshi.kani@hpe.com> - 2016-03-08 16:50 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Paul Gortmaker <paul.gortmaker@windriver.com> - 2016-03-10 15:50 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Toshi Kani <toshi.kani@hpe.com> - 2016-03-10 17:00 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Borislav Petkov <bp@suse.de> - 2016-03-10 18:30 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Paul Gortmaker <paul.gortmaker@windriver.com> - 2016-03-10 20:10 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Toshi Kani <toshi.kani@hpe.com> - 2016-03-10 20:20 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Borislav Petkov <bp@suse.de> - 2016-03-10 20:30 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-03-11 14:30 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Borislav Petkov <bp@suse.de> - 2016-03-11 14:50 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Paolo Bonzini <pbonzini@redhat.com> - 2016-03-11 20:20 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Borislav Petkov <bp@suse.de> - 2016-03-11 23:20 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Bruce Ashfield <bruce.ashfield@windriver.com> - 2016-03-11 23:30 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Richard Purdie <richard.purdie@linuxfoundation.org> - 2016-03-12 00:50 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Borislav Petkov <bp@suse.de> - 2016-03-12 13:10 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Toshi Kani <toshi.kani@hpe.com> - 2016-03-10 20:20 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Borislav Petkov <bp@suse.de> - 2016-03-10 20:30 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Toshi Kani <toshi.kani@hpe.com> - 2016-03-10 20:40 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Borislav Petkov <bp@suse.de> - 2016-03-10 22:10 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Toshi Kani <toshi.kani@hpe.com> - 2016-03-10 23:30 +0100
              Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Paul Gortmaker <paul.gortmaker@windriver.com> - 2016-03-08 04:20 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Toshi Kani <toshi.kani@hpe.com> - 2016-03-08 16:30 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Toshi Kani <toshi.kani@hpe.com> - 2016-03-08 17:10 +0100
                Re: runtime regression with "x86/mm/pat: Emulate PAT when it is  disabled" Paul Gortmaker <paul.gortmaker@windriver.com> - 2016-03-08 17:10 +0100

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