Re: [PATCH v3 0/4] BaseIoFifoLib

["Duran, Leo" <leo.duran@amd.com>]

> -----Original Message-----
> From: Laszlo Ersek [mailto:lersek@redhat.com]
> Sent: Monday, January 09, 2017 9:14 AM
> To: Duran, Leo <leo.duran@amd.com>; 'Gao, Liming'
> <liming.gao@intel.com>; Justen, Jordan L <jordan.l.justen@intel.com>;
> edk2-devel@lists.01.org <edk2-devel@ml01.01.org>
> Cc: Singh, Brijesh <brijesh.singh@amd.com>; Fan, Jeff <jeff.fan@intel.com>;
> Kinney, Michael D <michael.d.kinney@intel.com>; Ma, Maurice
> <maurice.ma@intel.com>; Agyeman, Prince <prince.agyeman@intel.com>;
> Ni, Ruiyu <ruiyu.ni@intel.com>; Steele, Kelly <kelly.steele@intel.com>; Wei,
> David <david.wei@intel.com>; Guo, Mang <mang.guo@intel.com>
> Subject: Re: [PATCH v3 0/4] BaseIoFifoLib
> 
> On 01/09/17 15:22, Duran, Leo wrote:
> >
> >> -----Original Message-----
> >> From: Gao, Liming [mailto:liming.gao@intel.com]
> >> Sent: Sunday, January 08, 2017 9:11 PM
> >> To: Duran, Leo <leo.duran@amd.com>; Justen, Jordan L
> >> <jordan.l.justen@intel.com>; 'Laszlo Ersek' <lersek@redhat.com>;
> >> edk2- devel@lists.01.org
> >> Cc: Singh, Brijesh <brijesh.singh@amd.com>; Fan, Jeff
> >> <jeff.fan@intel.com>; Kinney, Michael D <michael.d.kinney@intel.com>;
> >> Ma, Maurice <maurice.ma@intel.com>; Agyeman, Prince
> >> <prince.agyeman@intel.com>; Ni, Ruiyu <ruiyu.ni@intel.com>; Steele,
> >> Kelly <kelly.steele@intel.com>; Wei, David <david.wei@intel.com>;
> >> Guo, Mang <mang.guo@intel.com>
> >> Subject: RE: [PATCH v3 0/4] BaseIoFifoLib
> >>
> >> Leo:
> >>   IoLib Library class is designed from the functionality, not code
> >> implementation. So, many IO operations are included in this library
> >> class. If developers want to use IO API, they only need to check IoLib
> library class.
> >> After add new APIs, we need to update all IoLib library instances to
> >> implement them. And, if any library API implementation has the
> >> different version, the full library instance will have to be copied
> >> to another instance. I know your concern is to duplicate the library
> >> implementation. But, I think this is the separate topic to optimize
> >> the library implementation and reuse the same source file. Other
> >> library instances may have the same issue. So, I suggest you submit
> >> bugzilla for this optimization request. We will figure out the solution and
> review it in this mail list.
> >>
> >> Thanks
> >> Liming
> > [Duran, Leo]
> > Hi Liming,
> >
> > I'm not sure I follow what you mean by an 'optimization request'.
> 
> I think under "optimization", Liming means eliminating code duplication
> between IoLib library instances. That is, if I understand correctly, Liming and
> Jordan suggest that you first add the new interfaces to the IoLib class header,
> add (--> duplicate) the implementation to all library instances, then file a BZ
> about eliminating code duplication between the library instances.
> 
> This is my understanding anyway.
> 
> Thanks
> Laszlo
> 
[Duran, Leo]  Thanks Lazlo... Unfortunately the 'ask' is still not clear to me.
Liming,  I would appreciate some clarification.

Thanks,
Leo

> 
> > At present IoLIb does *not* include the Fifo routines that I've referred to,
> so I'm simply proposing to wrap the Fifo routines into in a library.
> > Moreover, as you just said, I’m also proposing not using IoLib to avoid
> having to duplicate all of the functionality in IoLib.
> >
> > Can you please give me a bit more detail as to what the 'optimization
> request' would be?
> > (i.e., should that request read exactly as I've proposed so far,
> > proposing the creation of an IoFifoLib?) I'll submit Bugzilla once I better
> understand what needs to be in it.
> >
> > Thanks,
> > Leo
> >
> >
> >
> >>> -----Original Message-----
> >>> From: Duran, Leo [mailto:leo.duran@amd.com]
> >>> Sent: Sunday, January 08, 2017 1:17 AM
> >>> To: Justen, Jordan L <jordan.l.justen@intel.com>; 'Laszlo Ersek'
> >>> <lersek@redhat.com>; Gao, Liming <liming.gao@intel.com>; edk2-
> >>> devel@lists.01.org
> >>> Cc: Singh, Brijesh <brijesh.singh@amd.com>; Fan, Jeff
> >>> <jeff.fan@intel.com>; Kinney, Michael D
> >>> <michael.d.kinney@intel.com>; Ma, Maurice <maurice.ma@intel.com>;
> >>> Agyeman, Prince <prince.agyeman@intel.com>; Ni, Ruiyu
> >>> <ruiyu.ni@intel.com>; Steele, Kelly <kelly.steele@intel.com>; Wei,
> >>> David <david.wei@intel.com>; Guo, Mang <mang.guo@intel.com>
> >>> Subject: RE: [PATCH v3 0/4] BaseIoFifoLib
> >>>
> >>> Jordan, Liming, et al,
> >>>
> >>> It turns out that the runtime enablement of SEV feature that I
> >>> referred to can be detected in hardware; so instead of requiring
> >>> 'driver' code to set a dynamic PCD, the override Fifo routines could
> >>> do a runtime check like this:
> >>>
> >>> // In override version of the Fifo library
> >>> fifo_foo()
> >>> {
> >>> 	If (SEV_Enabled()) {
> >>> 		// don't use REP ins/outs
> >>> 	} else {
> >>> 		// use REP ins/outs
> >>> 	}
> >>> }
> >>> In essence we already have a hardware-based dynamic PCD, so the idea
> >>> is to leverage it.
> >>>
> >>> And since we're interested in overriding just the Fifo routines, it
> >>> would make better sense to keep them in a separate library (as
> >>> proposed in
> >> the patch set).
> >>> Leo.
> >>>
> >>>> -----Original Message-----
> >>>> From: Jordan Justen [mailto:jordan.l.justen@intel.com]
> >>>> Sent: Friday, January 06, 2017 6:50 PM
> >>>> To: Duran, Leo <leo.duran@amd.com>; 'Laszlo Ersek'
> >>>> <lersek@redhat.com>; Gao, Liming <liming.gao@intel.com>;
> >>>> edk2-devel@lists.01.org
> >>>> Cc: Singh, Brijesh <brijesh.singh@amd.com>; Fan, Jeff
> >>>> <jeff.fan@intel.com>; Kinney, Michael D
> >>>> <michael.d.kinney@intel.com>; Ma, Maurice
> <maurice.ma@intel.com>;
> >>>> Agyeman, Prince <prince.agyeman@intel.com>; Ni, Ruiyu
> >>>> <ruiyu.ni@intel.com>; Steele, Kelly <kelly.steele@intel.com>; Wei,
> >>>> David <david.wei@intel.com>; Guo, Mang <mang.guo@intel.com>
> >>>> Subject: RE: [PATCH v3 0/4] BaseIoFifoLib
> >>>>
> >>>> On 2017-01-06 07:23:47, Duran, Leo wrote:
> >>>>>
> >>>>>
> >>>>>> -----Original Message-----
> >>>>>> From: Laszlo Ersek [mailto:lersek@redhat.com]
> >>>>>> Sent: Friday, January 06, 2017 5:12 AM
> >>>>>> To: Gao, Liming <liming.gao@intel.com>; Duran, Leo
> >>>>>> <leo.duran@amd.com>; edk2-devel@lists.01.org
> >>>>>> <edk2-devel@ml01.01.org>
> >>>>>> Cc: Singh, Brijesh <brijesh.singh@amd.com>; Justen, Jordan L
> >>>>>> <jordan.l.justen@intel.com>; Fan, Jeff <jeff.fan@intel.com>;
> >>>>>> Kinney, Michael D <michael.d.kinney@intel.com>; Ma, Maurice
> >>>>>> <maurice.ma@intel.com>; Agyeman, Prince
> >>>> <prince.agyeman@intel.com>;
> >>>>>> Ni, Ruiyu <ruiyu.ni@intel.com>; Steele, Kelly
> >>>>>> <kelly.steele@intel.com>; Wei, David <david.wei@intel.com>; Guo,
> >>>>>> Mang <mang.guo@intel.com>
> >>>>>> Subject: Re: [PATCH v3 0/4] BaseIoFifoLib
> >>>>>>
> >>>>>> On 01/06/17 07:02, Gao, Liming wrote:
> >>>>>>> Leo:
> >>>>>>> FifoIo is one width type of EFI_CPU_IO_PROTOCOL_WIDTH. So,
> how
> >>>>>>> about add new APIs into IoLib together with other Io APIs? If
> >>>>>>> so, no new library class is required. Platform DSC files are not
> >>>>>>> required to be changed.
> >>>>>>
> >>>>>> But then all of the IoLib instances will have to be extended too:
> >>>>>>
> >>>>>> IntelFrameworkPkg/Library/DxeIoLibCpuIo/DxeIoLibCpuIo.inf
> >>>>>> MdePkg/Library/BaseIoLibIntrinsic/BaseIoLibIntrinsic.inf
> >>>>>> MdePkg/Library/DxeIoLibCpuIo2/DxeIoLibCpuIo2.inf
> >>>>>> MdePkg/Library/DxeIoLibEsal/DxeIoLibEsal.inf
> >>>>>> MdePkg/Library/PeiIoLibCpuIo/PeiIoLibCpuIo.inf
> >>>>>> MdePkg/Library/SmmIoLibSmmCpuIo2/SmmIoLibSmmCpuIo2.inf
> >>>>>>
> >>>>>> Thanks,
> >>>>>> Laszlo
> >>>>>>
> >>>>> [Duran, Leo] Correct.
> >>>>> As I mentioned, one of the reasons for the new IoFifo library is
> >>>>> to be able to override it without having to duplicate the complete
> IoLib.
> >>>>>
> >>>>
> >>>> I agree with Liming about adding the functions to IoLib instead.
> >>>>
> >>>> Perhaps a PCD could be added to control if rep i/o instructions are
> >>>> used.
> >>>>
> >>>> -Jordan