On 02/01/18 03:09, Song, BinX wrote:
> Hi Laszlo,
>
> Thanks for your comments.
> Explain the issue first:
> In CpuCommonFeaturesLib.inf -> CpuCommonFeaturesLib.c ->
> CpuCommonFeaturesLibConstructor() function,
> it invokes RegisterCpuFeature() to register CPU feature. Some original source
> codes is here.
> if (IsCpuFeatureSupported (CPU_FEATURE_AESNI)) {
> Status = RegisterCpuFeature (
> "AESNI",
> AesniGetConfigData,
> AesniSupport,
> AesniInitialize,
> CPU_FEATURE_AESNI,
> CPU_FEATURE_END
> );
> ASSERT_EFI_ERROR (Status);
> }
> if (IsCpuFeatureSupported (CPU_FEATURE_MWAIT)) {
> Status = RegisterCpuFeature (
> "MWAIT",
> NULL,
> MonitorMwaitSupport,
> MonitorMwaitInitialize,
> CPU_FEATURE_MWAIT,
> CPU_FEATURE_END
> );
> ASSERT_EFI_ERROR (Status);
> }
>
> Then I update them to below.
> if (IsCpuFeatureSupported (CPU_FEATURE_AESNI)) {
> Status = RegisterCpuFeature (
> "AESNI",
> AesniGetConfigData,
> AesniSupport,
> AesniInitialize,
> CPU_FEATURE_AESNI,
> CPU_FEATURE_MWAIT | CPU_FEATURE_BEFORE,
> CPU_FEATURE_END
> );
> ASSERT_EFI_ERROR (Status);
> }
> if (IsCpuFeatureSupported (CPU_FEATURE_MWAIT)) {
> Status = RegisterCpuFeature (
> "MWAIT",
> NULL,
> MonitorMwaitSupport,
> MonitorMwaitInitialize,
> CPU_FEATURE_MWAIT,
> CPU_FEATURE_AESNI | CPU_FEATURE_BEFORE,
> CPU_FEATURE_END
> );
> ASSERT_EFI_ERROR (Status);
> }
> Original function CheckCpuFeaturesDependency() will enter a dead loop and
> prompt nothing when checking and sorting them.
Ah, I see, so the RegisterCpuFeature() call can add before/after hints
to the features. And circular dependencies cause an infinite loop currently.
> I think a better way is to detect this conflicted logic and give some hints
> to user, then assert(false).
>
> For your three comments.
> 1. How about change to this?
> if (BeforeFlag) {
> DEBUG ((DEBUG_ERROR, "Error: Feature %a before condition is invalid!",
> CurrentCpuFeature->FeatureName));
> } else {
> DEBUG ((DEBUG_ERROR, "Error: Feature %a after condition is invalid!",
> CurrentCpuFeature->FeatureName));
> }
It's OK to do this as well:
DEBUG ((
DEBUG_ERROR,
"Error: Feature %a %a condition is invalid!\n",
CurrentCpuFeature->FeatureName,
BeforeFlag ? "before" : "after"
));
> 2. Will update it in V2 patch.
> 3. How about add a prefix before the name?
> RegisterCpuFeaturesLibSortCpuFeatures() will be unique.
Sure.
Thanks!
Laszlo
>
> Best Regards,
> Bell Song
>
>> -----Original Message-----
>> From: Laszlo Ersek [mailto:[email protected]]
>> Sent: Wednesday, January 31, 2018 5:44 PM
>> To: Song, BinX <[email protected]>; [email protected]
>> Cc: Dong, Eric <[email protected]>
>> Subject: Re: [PATCH] UefiCpuPkg: Enhance CPU feature dependency check
>>
>> On 01/31/18 08:00, Song, BinX wrote:
>>> Current CPU feature dependency check will hang on when meet below or
>>> similar case:
>>> if (IsCpuFeatureSupported (CPU_FEATURE_AESNI)) {
>>> Status = RegisterCpuFeature (
>>> "AESNI",
>>> AesniGetConfigData,
>>> AesniSupport,
>>> AesniInitialize,
>>> CPU_FEATURE_AESNI,
>>> CPU_FEATURE_MWAIT | CPU_FEATURE_BEFORE,
>>> CPU_FEATURE_END
>>> );
>>> ASSERT_EFI_ERROR (Status);
>>> }
>>> if (IsCpuFeatureSupported (CPU_FEATURE_MWAIT)) {
>>> Status = RegisterCpuFeature (
>>> "MWAIT",
>>> NULL,
>>> MonitorMwaitSupport,
>>> MonitorMwaitInitialize,
>>> CPU_FEATURE_MWAIT,
>>> CPU_FEATURE_AESNI | CPU_FEATURE_BEFORE,
>>> CPU_FEATURE_END
>>> );
>>> ASSERT_EFI_ERROR (Status);
>>> }
>>>
>>> Solution is to separate current CPU feature dependency check into
>>> sort and check two parts.
>>>
>>> Sort function:
>>> According to CPU feature's dependency, sort all CPU features.
>>> Later dependency will override previous dependency if they are conflicted.
>>>
>>> Check function:
>>> Check sorted CPU features' relationship, ASSERT invalid relationship.
>>>
>>> Cc: Eric Dong <[email protected]>
>>> Cc: Laszlo Ersek <[email protected]>
>>> Contributed-under: TianoCore Contribution Agreement 1.1
>>> Signed-off-by: Bell Song <[email protected]>
>>> ---
>>> .../RegisterCpuFeaturesLib/CpuFeaturesInitialize.c | 271
>> ++++++++++++++++++++-
>>> .../RegisterCpuFeaturesLib/RegisterCpuFeatures.h | 7 +
>>> .../RegisterCpuFeaturesLib.c | 130 +---------
>>> 3 files changed, 278 insertions(+), 130 deletions(-)
>>>
>>> diff --git
>> a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
>> b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
>>> index 4d75c07..2fd0d5f 100644
>>> --- a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
>>> +++ b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
>>> @@ -423,6 +423,271 @@ DumpRegisterTableOnProcessor (
>>> }
>>>
>>> /**
>>> + From FeatureBitMask, find the right feature entry in CPU feature list.
>>> +
>>> + @param[in] FeatureList The pointer to CPU feature list.
>>> + @param[in] CurrentFeature The pointer to current CPU feature.
>>> + @param[in] BeforeFlag TRUE: BeforeFeatureBitMask; FALSE:
>> AfterFeatureBitMask.
>>> +
>>> + @return The pointer to right CPU feature entry.
>>> +**/
>>> +LIST_ENTRY *
>>> +FindFeatureInList(
>>> + IN LIST_ENTRY *CpuFeatureList,
>>> + IN CPU_FEATURES_ENTRY *CurrentCpuFeature,
>>> + IN BOOLEAN BeforeFlag
>>> + )
>>> +{
>>> + LIST_ENTRY *TempEntry;
>>> + CPU_FEATURES_ENTRY *TempFeature;
>>> + UINT8 *FeatureBitMask;
>>> +
>>> + FeatureBitMask = BeforeFlag ? CurrentCpuFeature-
>>> BeforeFeatureBitMask : CurrentCpuFeature->AfterFeatureBitMask;
>>> + TempEntry = GetFirstNode (CpuFeatureList);
>>> + while (!IsNull (CpuFeatureList, TempEntry)) {
>>> + TempFeature = CPU_FEATURE_ENTRY_FROM_LINK (TempEntry);
>>> + if (IsBitMaskMatchCheck (FeatureBitMask, TempFeature-
>>> FeatureMask)){
>>> + return TempEntry;
>>> + }
>>> + TempEntry = TempEntry->ForwardLink;
>>> + }
>>> +
>>> + DEBUG ((DEBUG_ERROR, "Error: Feature %a ", CurrentCpuFeature-
>>> FeatureName, BeforeFlag ? "before ":"after ", "condition is invalid!\n"));
>>
>> Hi, I skimmed this patch quickly -- I can tell that I can't really tell
>> what's going on. I don't know how the feature dependencies are defined
>> in the first place, and what the bug is.
>>
>> However, I do see that the above DEBUG macro invocation is incorrect.
>> The format string has one (1) %a conversion specification, but we pass
>> three (3) arguments.
>>
>> I think the last argument ("condition is invalid!\n") should actually be
>> part of the format string. And then, the "before"/"after" string has to
>> be printed somehow as well.
>>
>> Another superficial observation below:
>>
>>> +/**
>>> + Check sorted CPU features' relationship, ASSERT invalid one.
>>> +
>>> + @param[in] FeatureList The pointer to CPU feature list.
>>> +**/
>>> +VOID
>>> +CheckCpuFeaturesRelationShip (
>>
>> I don't think we should capitalize "Ship" in this identifier.
>>
>> Third comment: there are several ways to define "sorting", so I'm not
>> sure my question applies, but: can we replace the manual sorting with
>> SortLib?
>>
>> Thanks
>> Laszlo
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