Re: [Xen-devel] [PATCH v4 05/16] libxl/arm: Construct ACPI RSDP table

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Tue, 30 Aug 2016, Julien Grall wrote:
> Hi Shannon,
> 
> On 30/08/16 02:21, Shannon Zhao wrote:
> > 
> > 
> > On 2016/8/30 2:05, Julien Grall wrote:
> > > Hi Shannon,
> > > 
> > > On 25/08/2016 04:05, Shannon Zhao wrote:
> > > > 
> > > > 
> > > > On 2016/8/24 20:52, Wei Liu wrote:
> > > > > On Tue, Aug 16, 2016 at 06:25:02PM +0800, Shannon Zhao wrote:
> > > > > > > From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> > > > > > > 
> > > > > > > Construct ACPI RSDP table and add a helper to calculate the ACPI
> > > > > > > table
> > > > > > > checksum.
> > > > > > > 
> > > > > > > Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> > > > > > > ---
> > > > > > >  tools/libxl/libxl_arm_acpi.c | 38
> > > > > > > ++++++++++++++++++++++++++++++++++++++
> > > > > > >  1 file changed, 38 insertions(+)
> > > > > > > 
> > > > > > > diff --git a/tools/libxl/libxl_arm_acpi.c
> > > > > > > b/tools/libxl/libxl_arm_acpi.c
> > > > > > > index 6be9eb0..9432e44 100644
> > > > > > > --- a/tools/libxl/libxl_arm_acpi.c
> > > > > > > +++ b/tools/libxl/libxl_arm_acpi.c
> > > > > > > @@ -33,6 +33,9 @@ extern const unsigned char dsdt_anycpu_arm[];
> > > > > > >  _hidden
> > > > > > >  extern const int dsdt_anycpu_arm_len;
> > > > > > > 
> > > > > > > +#define ACPI_BUILD_APPNAME6 "XenARM"
> > > > > > > +#define ACPI_BUILD_APPNAME4 "Xen "
> > > > > > > +
> > > > > Where do these come from? If they are from a spec, could you please
> > > > > add
> > > > > a comment here?
> > > > > 
> > > > Not from some spec. Just fake a OEM for these tables like the
> > > > ACPI_OEM_ID, ACPI_CREATOR_ID used by x86.
> > > 
> > > In this case, why don't we re-use the one from x86?
> > > 
> > While the ACPI_OEM_TABLE_ID and ACPI_CREATOR_ID of x86 are HVM specific,
> > I don't think it's proper for ARM.
> 
> IIRC we have an OEM ID and Creator ID reserved for Xen. Stefano can you
> confirm?
>
> In any case, it would be better if we re-use the existing one. It does not
> hurt to use a different name. For instance the signature of the MADT table is
> "APIC" with is x86 specific...

I think it makes sense to use the same OEM id as x86, which seems to be
"Xen", but I am not sure about who reserved it, it predates me. I would
change the creator id, because it is "HVML" on x86, for "HVM Loader".
Maybe we could use "xl". FYI creator id is the id of the utility that
generated the tables.

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