Re: [PATCH 1/2] acpi/nvdimm: Create _LS{I,R,W} method for NVDIMM device

[Igor Mammedov <imammedo@redhat.com>]

On Fri, 29 Apr 2022 17:01:47 +0800
Robert Hoo <robert.hu@linux.intel.com> wrote:

> On Wed, 2022-04-27 at 16:34 +0200, Igor Mammedov wrote:
> > On Tue, 12 Apr 2022 14:57:52 +0800
> > Robert Hoo <robert.hu@linux.intel.com> wrote:
> >   
> > > Since ACPI 6.2, previous NVDIMM/_DSM funcions "Get Namespace Label
> > > Data
> > > Size (function index 4)", "Get Namespace Label Data (function index
> > > 5)",
> > > "Set Namespace Label Data (function index 6)" has been deprecated
> > > by ACPI  
> > 
> > where it's said that old way was deprecated, should be mentioned here
> > including
> > pointer to spec where it came into effect.  
> 
> OK. https://pmem.io/documents/IntelOptanePMem_DSM_Interface-V2.0.pdf,
> 3.10 Deprecated Functions.
> I put it in cover letter. Will also mention it here.
> >   
> ...
> > > 
> > > diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
> > > index 0d43da19ea..7cc419401b 100644
> > > --- a/hw/acpi/nvdimm.c
> > > +++ b/hw/acpi/nvdimm.c
> > > @@ -848,10 +848,10 @@ nvdimm_dsm_write(void *opaque, hwaddr addr,
> > > uint64_t val, unsigned size)
> > >  
> > >      nvdimm_debug("Revision 0x%x Handler 0x%x Function 0x%x.\n",
> > > in->revision,
> > >                   in->handle, in->function);
> > > -
> > > -    if (in->revision != 0x1 /* Currently we only support DSM Spec
> > > Rev1. */) {
> > > -        nvdimm_debug("Revision 0x%x is not supported, expect
> > > 0x%x.\n",
> > > -                     in->revision, 0x1);
> > > +    /* Currently we only support DSM Spec Rev1 and Rev2. */  
> > 
> > where does revision 2 come from? It would be better to add a pointer
> > to relevant spec.  
> 
> https://pmem.io/documents/IntelOptanePMem_DSM_Interface-V2.0.pdf,
> Section 3 "_DSM Interface for the NVDIMM Device", table 3-A and 3-B.
> 
> I'll add this in comments in next version.
> >   
> > > +    if (in->revision != 0x1 && in->revision != 0x2) {
> > > +        nvdimm_debug("Revision 0x%x is not supported, expect 0x1
> > > or 0x2.\n",
> > > +                     in->revision);  
> > 
> > since you are touching nvdimm_debug(), please replace it with
> > tracing,
> > see docs/devel/tracing.rst and any commit that adds tracing calls
> > (functions starting with 'trace_').  
> 
> OK I'll have a try.

just make conversion a separate patch

> >   
> > >          nvdimm_dsm_no_payload(NVDIMM_DSM_RET_STATUS_UNSUPPORT,
> > > dsm_mem_addr);
> > >          goto exit;
> > >      }  
> > 
> > 
> > this whole hunk should be a separate patch, properly documented
> >   
> OK
> > 
> > also I wonder if DSM  
> 
> It's not in SDM, but above-mentioned _DSM Interface spec by Intel.
> >   
> > > @@ -1247,6 +1247,11 @@ static void nvdimm_build_fit(Aml *dev)
> > >  static void nvdimm_build_nvdimm_devices(Aml *root_dev, uint32_t
> > > ram_slots)
> > >  {
> > >      uint32_t slot;
> > > +    Aml *method, *pkg, *buff;
> > > +
> > > +    /* Build common shared buffer for params pass in/out */
> > > +    buff = aml_buffer(4096, NULL);
> > > +    aml_append(root_dev, aml_name_decl("BUFF", buff));  
> > 
> > is there a reason to use global variable instead of LocalX?  
> 
> Local in root_dev but global to its sub devices? I think it is doable.
> 
> But given your below comments on return param _LS{I,R,W}, I now think,
> in v2, I'm not going to reuse existing "NCAL" method, but implement
> _LS{I,R,W} their own, stringently follow interface spec. Then, no buff
> required at all. How do you like this?
> >   
> > >  
> > >      for (slot = 0; slot < ram_slots; slot++) {
> > >          uint32_t handle = nvdimm_slot_to_handle(slot);
> > > @@ -1264,6 +1269,49 @@ static void nvdimm_build_nvdimm_devices(Aml
> > > *root_dev, uint32_t ram_slots)
> > >           */
> > >          aml_append(nvdimm_dev, aml_name_decl("_ADR",
> > > aml_int(handle)));
> > >  
> > > +        /* Build _LSI, _LSR, _LSW */  
> > 
> > should be 1 comment per method with spec/ver and chapter where it's
> > defined  
> 
> OK
> >   
> > > +        method = aml_method("_LSI", 0, AML_NOTSERIALIZED);
> > > +        aml_append(method, aml_return(aml_call5(NVDIMM_COMMON_DSM,
> > > +                            aml_touuid("4309AC30-0D11-11E4-9191-
> > > 0800200C9A66"),
> > > +                            aml_int(2), aml_int(4), aml_int(0),
> > > +                            aml_int(handle))));
> > > +        aml_append(nvdimm_dev, method);  
> > 
> > _LSI should return Package  
> 
> Right. See above.
> >   
> > > +        method = aml_method("_LSR", 2, AML_SERIALIZED);
> > > +        aml_append(method,
> > > +            aml_create_dword_field(aml_name("BUFF"), aml_int(0),
> > > "DWD0"));
> > > +        aml_append(method,
> > > +            aml_create_dword_field(aml_name("BUFF"), aml_int(4),
> > > "DWD1"));  
> > 
> > theoretically aml_create_dword_field() takes TermArg as source
> > buffer,
> > so it doesn't have to be a global named buffer.
> > Try keep buffer in LocalX variable and check if it works in earliest
> > Windows version that supports NVDIMMs. If it does then drop BUFF and
> > use
> > Local variable, if not then that fact should be mentioned in commit
> > message/patch  
> 
> Thanks Igor. I'm new to asl grammar, I'll take your advice.
> 
> >   
> > > +        pkg = aml_package(1);
> > > +        aml_append(pkg, aml_name("BUFF"));
> > > +        aml_append(method, aml_name_decl("PKG1", pkg));
> > > +        aml_append(method, aml_store(aml_arg(0),
> > > aml_name("DWD0")));
> > > +        aml_append(method, aml_store(aml_arg(1),
> > > aml_name("DWD1")));  
> > 
> > perhaps use less magical names for fields, something like:
> >   DOFF
> >   TLEN
> > add appropriate comments  
> 
> No problem.
> > 
> > Also I'd prepare/fill in buffer first and only then declare
> > initialize
> > Package + don't use named object for Package if it can be done with
> > help
> > of Local variables.
> >   
> > > +        aml_append(method, aml_return(aml_call5(NVDIMM_COMMON_DSM,
> > > +                            aml_touuid("4309AC30-0D11-11E4-9191-
> > > 0800200C9A66"),
> > > +                            aml_int(2), aml_int(5),
> > > aml_name("PKG1"),
> > > +                            aml_int(handle))));  
> > 
> > this shall return Package not a Buffer  
> 
> Right, Going to re-implement these methods rather than wrapper NCAL.

wrapper is fine, you just need to repackage content of the Buffer
into a Package

> >   
> > > +        aml_append(nvdimm_dev, method);
> > > +
> > > +        method = aml_method("_LSW", 3, AML_SERIALIZED);
> > > +        aml_append(method,
> > > +            aml_create_dword_field(aml_name("BUFF"), aml_int(0),
> > > "DWD0"));
> > > +        aml_append(method,
> > > +            aml_create_dword_field(aml_name("BUFF"), aml_int(4),
> > > "DWD1"));
> > > +        aml_append(method,
> > > +            aml_create_field(aml_name("BUFF"), aml_int(64),
> > > aml_int(32672), "FILD"));
> > > +        pkg = aml_package(1);
> > > +        aml_append(pkg, aml_name("BUFF"));
> > > +        aml_append(method, aml_name_decl("PKG1", pkg));
> > > +        aml_append(method, aml_store(aml_arg(0),
> > > aml_name("DWD0")));
> > > +        aml_append(method, aml_store(aml_arg(1),
> > > aml_name("DWD1")));
> > > +        aml_append(method, aml_store(aml_arg(2),
> > > aml_name("FILD")));
> > > +        aml_append(method, aml_return(aml_call5(NVDIMM_COMMON_DSM,
> > > +                            aml_touuid("4309AC30-0D11-11E4-9191-
> > > 0800200C9A66"),
> > > +                            aml_int(2), aml_int(6),
> > > aml_name("PKG1"),
> > > +                            aml_int(handle))));  
> > 
> > should return Integer not Buffer, it looks like implicit conversion
> > will take care of it,
> > but it would be better to explicitly convert it to Integer even if
> > it's only for the sake
> > of documenting expected return value (or add a comment)  
> 
> I observed guest kernel ACPI component complaining this; just warning,
> no harm. I'll re-implement it.

try to test it with Windows guest (it usually less tolerable to errors
than Linux + it's own quirks that you need to carter to)
Also it would e nice if you test and put results in cover letter
not only for Linux but for Windows as well.

> > 
> > Also returned value in case of error NVDIMM_DSM_RET_STATUS_INVALID,
> > in NVDIMM and ACPI spec differ. So fix the spec or remap returned
> > value.
> > 
> >   
> > > +        aml_append(nvdimm_dev, method);
> > > +
> > >          nvdimm_build_device_dsm(nvdimm_dev, handle);
> > >          aml_append(root_dev, nvdimm_dev);
> > >      }  
> > 
> >   
>