Re: [Xen-devel] [PATCH RESEND 07/14] libxl/arm: Construct ACPI DSDT table

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 16 Jun 2016, Julien Grall wrote:
> Hi Shannon,
> 
> On 16/06/16 07:25, Shannon Zhao wrote:
> > 
> > 
> > On 2016/6/7 21:42, Julien Grall wrote:
> > > Hello Shannon,
> > > 
> > > On 31/05/16 06:02, Shannon Zhao wrote:
> > > > From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> > > > 
> > > > Currently there is only the table header in DSDT table.
> > > > 
> > > > Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> > > > ---
> > > >    tools/libxl/libxl_arm.c | 15 +++++++++++++++
> > > >    1 file changed, 15 insertions(+)
> > > > 
> > > > diff --git a/tools/libxl/libxl_arm.c b/tools/libxl/libxl_arm.c
> > > > index c3b8fb4..7949635 100644
> > > > --- a/tools/libxl/libxl_arm.c
> > > > +++ b/tools/libxl/libxl_arm.c
> > > > @@ -944,6 +944,20 @@ static void make_acpi_fadt(libxl__gc *gc, struct
> > > > xc_dom_image *dom)
> > > >        dom->acpitable_size += dom->acpitable_blob->fadt.size;
> > > >    }
> > > > 
> > > > +static void make_acpi_dsdt(libxl__gc *gc, struct xc_dom_image *dom)
> > > > +{
> > > > +    struct acpi_table_header *dsdt;
> > > > +
> > > > +    /* Currently there is only the table header in DSDT table. */
> > > 
> > > What about the processor device objects?
> > 
> > Ah, yes. It should add processor device objects. Since DSDT table is
> > special, what's your suggestion about how to generate DSDT table? Use
> > static table which X86 use(tools/firmware/hvmloader/acpi/mk_dsdt.c) or
> > import what QEMU uses?
> 
> I would do the choice depending on what we need to expose through the DTST. If
> it is only dummy processor containers, then ~1500 lines of code (see
> qemu/hw/acpi/aml-build.c) seems a bit overkill.
> 
> > I prefer the latter, but this will add more codes to libxl.
> 
> What would be the benefits to build dynamically those tables?

Indeed, this is the right question. If we can get away with static
tables like on x86, we should. Less code is always better than more code
:-)

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