Question about mtrr test

[Alex Hung]

Hi Eric,

Thanks for the information.

FWTS does not read msr directly (requires rdmsr instruction + ring0);
however, Linux kernel uses it and it prints the default in dmesg, ex.
MTRR default type: write-back)  We may be able to figure something
out.

Cheers,
Alex Hung

On Thu, Jul 14, 2016 at 8:46 PM, Dong, Eric <eric.dong at intel.com> wrote:
> Hi Alex,
>
> I don't use linux environment to do the test. So I don't have the /proc/mtrr and /proc/iomem info.
>
> From Intel IA32 manual,  you can get the default memory type info from MSR  IA32_MTRR_DEF_TYPE.
>
> Thanks,
> Eric
>> -----Original Message-----
>> From: Alex Hung [mailto:alex.hung at canonical.com]
>> Sent: Thursday, July 14, 2016 7:59 PM
>> To: Dong, Eric
>> Cc: Colin Ian King; fwts-devel at lists.ubuntu.com
>> Subject: Re: Question about mtrr test
>>
>> the FWTS version is V16.05.01 according to the attached file "fwts"
>>
>> the fwts results (i.e. fwts") also listed the mtrr (probably from
>> /proc/mtrr) as below:
>>
>> mtrr           ;INF Reg 0: 0x00000000c0000000 - 0x00000000ffffffff (
>> 1024 MB)   Uncached
>> mtrr           ;INF Reg 1: 0x00000000bf800000 - 0x00000000bfffffff (
>>   8 MB)   Uncached
>>
>> Everything before 0xC0000000 and after 0xbfffffff are not specified,
>> according to Linux kernel (ex. 4.5.0-yocto-standard).
>>
>> As far as FWTS's concerns, it is the results look right...  Will you
>> be able to provide the ouput of the following?
>>
>> 1. cat /proc/mtrr
>> 2. cat /proc/iomem
>>
>> PS. In theory default cache mechanism can be read from CR0 register,
>> but I haven't figured out how to do it in FWTS as it can only be read
>> in ring0...
>>
>> On Thu, Jul 14, 2016 at 6:44 PM, Dong, Eric <eric.dong at intel.com> wrote:
>> > Colin,
>> >
>> > Thanks for your quick response.
>> >
>> >> -----Original Message-----
>> >> From: Colin Ian King [mailto:colin.king at canonical.com]
>> >> Sent: Thursday, July 14, 2016 6:27 PM
>> >> To: Dong, Eric; fwts-devel at lists.ubuntu.com
>> >> Subject: Re: Question about mtrr test
>> >>
>> >> On 14/07/16 11:08, Dong, Eric wrote:
>> >> > I use LUV v2.1-rc1 image to do the test, not sure the Fwts version. I think it is Fwts V16.06.00.
>> >> >
>> >> >
>> >> >> -----Original Message-----
>> >> >> From: Colin Ian King [mailto:colin.king at canonical.com]
>> >> >> Sent: Thursday, July 14, 2016 6:00 PM
>> >> >> To: Dong, Eric; fwts-devel at lists.ubuntu.com
>> >> >> Subject: Re: Question about mtrr test
>> >> >>
>> >> >> On 14/07/16 10:58, Dong, Eric wrote:
>> >> >>> Hi,
>> >> >>>
>> >> >>>
>> >> >>>
>> >> >>> I use Fwts to test the uefi bios, it reported below errors:
>> >> >>>
>> >> >>>
>> >> >>>
>> >> >>> mtrr           ;HED mtrr: MTRR tests.
>> >> >>>
>> >> >>> mtrr           ;SEP
>> >> >>> ------------------------------------------------------------
>> >> >>>
>> >> >>> mtrr           ;INF MTRR overview
>> >> >>>
>> >> >>> mtrr           ;INF -------------
>> >> >>>
>> >> >>> mtrr           ;INF Reg 0: 0x00000000c0000000 - 0x0000000100000000 (
>> >> >>> 1024 MB)   Uncached
>> >> >>>
>> >> >>> mtrr           ;INF Reg 1: 0x00000000bf800000 - 0x00000000c0000000 (
>> >> >>> 8 MB)   Uncached
>> >> >>>
>> >> >>> mtrr           ;NLN
>> >> >>>
>> >> >>> mtrr           ;INF Test 1 of 3: Validate the kernel MTRR IOMEM setup.
>> >> >>>
>> >> >>> mtrr           ;FAL FAILED [MEDIUM] MTRRIncorrectAttr: Test 1, Memory range
>> >> >>>
>> >> >>> mtrr           ;FAL 0x1000 to 0x5efff (System RAM) has incorrect attribute
>> >> >>>
>> >> >>> mtrr           ;FAL Default (Most probably Uncached).
>> >> >>>
>> >> >>> mtrr           ;FAL FAILED [MEDIUM] MTRRLackingAttr: Test 1, Memory
>> >> >>> range 0x1000
>> >> >>>
>> >> >>> mtrr           ;FAL to 0x5efff (System RAM) is lacking attribute Write-Back.
>> >> >>>
>> >> >>>
>> >> >>>
>> >> >>> But we already update the IA32_MTRR_DEF_TYPE (0x2FF) to set the default
>> >> >>> type to Write-Back. If update the IA32_MTRR_DEF_TYPE to set the default
>> >> >>> type to Uncached.  These errors will not occur. I think this is Fwts
>> >> >>> tools issue. It should check the default type from IA32_MTRR_DEF_TYPE
>> >> >>> before run this test.  Any feedback about it?
>> >>
>> >> OK, I think thats a bug, thanks for reporting that. I've filed it under:
>> >> https://bugs.launchpad.net/ubuntu/+source/fwts/+bug/1603026
>> >>
>> >> Any ideas Ivan/Alex?
>> >>
>> >> Colin
>> >> >>>
>> >> >>>
>> >> >>>
>> >> >>> Thanks,
>> >> >>>
>> >> >>> Eric
>> >> >>>
>> >> >>>
>> >> >>>
>> >> >>> This body part will be downloaded on demand.
>> >> >>>
>> >> >>
>> >> >> Eric, which version of fwts are you using?
>> >> >>
>> >> >
>> >
>> >
>> > --
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>>
>>
>>
>> --
>> Cheers,
>> Alex Hung



-- 
Cheers,
Alex Hung