Re: [PATCH v3 4/5] hw/acpi/aml-build: Update the revision of PPTT table

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Apr 23, 2025 at 04:47:20PM +0100, Jonathan Cameron wrote:
> On Wed, 23 Apr 2025 11:35:46 -0400
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
> > On Wed, Apr 23, 2025 at 10:15:42PM +0800, Yicong Yang wrote:
> > > On 2025/4/23 20:39, Michael S. Tsirkin wrote:  
> > > > On Wed, Apr 23, 2025 at 12:41:29PM +0100, Alireza Sanaee wrote:  
> > > >> From: Yicong Yang <yangyicong@hisilicon.com>
> > > >>
> > > >> The lastest ACPI spec 6.5 support PPTT revision 3. Update it
> > > >> by handy. This is compatible with previous revision.
> > > >>
> > > >> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
> > > >> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> > > >> Signed-off-by: Alireza Sanaee <alireza.sanaee@huawei.com>  
> > > > 
> > > > 
> > > > I don't get it. Why are you updating it? Which features
> > > > from the new one are you using?
> > > >   
> > > 
> > > no new features for this patchset. considered updating it to the latest ACPI
> > > spec since we're going to touch the PPTT table and tested data.  
> > 
> > it's best to wait until there are actual features you need.
> > don't make changes for the sake of changes, there's always
> > some risk.
> 
> Once we add the cache description (Ali's other set) can we make
> sure we arbitrary decide to have separate cache structures.  The
> earlier table version allowed sharing of the entrees in the table
> which then became not allowed in the newer spec. That will smooth
> the path quite a bit and is a valid way to interpret the earlier spec.
> 
> If we do that, we can bring the IDs + the version update as a
> precursor to MPAM support series. I don't think we need them until
> that series (which is a way off being ready to merge yet!)
> 
> Jonathan

Why not. Sounds like all that can be made part of Ali's patchset?
I am also ok to merge things gradually, as long as it's
clear and documented in the commit log why we are
making the change and where things are going.

> > 
> > > >> ---
> > > >>  hw/acpi/aml-build.c | 2 +-
> > > >>  1 file changed, 1 insertion(+), 1 deletion(-)
> > > >>
> > > >> diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
> > > >> index 3010325ca423..e5401dfdb1a8 100644
> > > >> --- a/hw/acpi/aml-build.c
> > > >> +++ b/hw/acpi/aml-build.c
> > > >> @@ -2155,7 +2155,7 @@ void build_pptt(GArray *table_data, BIOSLinker *linker, MachineState *ms,
> > > >>      uint32_t pptt_start = table_data->len;
> > > >>      uint32_t root_offset;
> > > >>      int n;
> > > >> -    AcpiTable table = { .sig = "PPTT", .rev = 2,
> > > >> +    AcpiTable table = { .sig = "PPTT", .rev = 3,
> > > >>                          .oem_id = oem_id, .oem_table_id = oem_table_id };
> > > >>  
> > > >>      acpi_table_begin(&table, table_data);
> > > >> -- 
> > > >> 2.34.1  
> > > > 
> > > > 
> > > > .
> > > >   
> > 
> >