Re: [Qemu-devel] [PATCH hack dontapply v2 7/7] pc: HACK: acpi: tie in _CST object to Processor

[Igor Mammedov <imammedo@redhat.com>]

On Wed, 25 Jul 2018 15:50:09 +0300
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Wed, Jul 25, 2018 at 02:37:24PM +0200, Igor Mammedov wrote:
> > On Tue, 10 Jul 2018 03:01:34 +0300
> > "Michael S. Tsirkin" <mst@redhat.com> wrote:
> >   
> > > Based on patch by Igor Mammedov.
> > > 
> > > This is a hack: we definitely shouldn't do it
> > > unconditionally, and initialization should be handled
> > > differently (through an isa device?). io port to use
> > > should depend on the PC type and should be documented.
> > > 
> > > Notifications should be supported.
> > > 
> > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > > ---
> > >  include/hw/i386/pc.h |  5 +++++
> > >  hw/acpi/cpu.c        |  5 +++++
> > >  hw/i386/acpi-build.c | 10 +++++++++-
> > >  3 files changed, 19 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> > > index 316230e570..83b3a84322 100644
> > > --- a/include/hw/i386/pc.h
> > > +++ b/include/hw/i386/pc.h
> > > @@ -20,6 +20,11 @@
> > >  
> > >  #define HPET_INTCAP "hpet-intcap"
> > >  
> > > +typedef struct PCCstate {
> > > +    uint32_t latency;
> > > +    uint32_t hint;
> > > +} PCCstate;
> > > +
> > >  /**
> > >   * PCMachineState:
> > >   * @acpi_dev: link to ACPI PM device that performs ACPI hotplug handling
> > > diff --git a/hw/acpi/cpu.c b/hw/acpi/cpu.c
> > > index 5ae595ecbe..e9e207b033 100644
> > > --- a/hw/acpi/cpu.c
> > > +++ b/hw/acpi/cpu.c
> > > @@ -561,6 +561,11 @@ void build_cpus_aml(Aml *table, MachineState *machine, CPUHotplugFeatures opts,
> > >                             aml_int(arch_ids->cpus[i].props.node_id)));
> > >              }
> > >  
> > > +            if (1) {
> > > +                method = aml_method("_CST", 0, AML_NOTSERIALIZED);
> > > +                aml_append(method, aml_return(aml_call0("CCST")));  
> > in case of not loaded CCST it would be unresolved reference.
> > It would be better to have a package /SB.CPUS.CCST filled with some startup values
> > and than that could be updated on the fly with new package.  
> 
> I think it will conflict if we do. But yes we could load \SB.CCST and
> then \SB.CPUS.CCST will override that. Would it help though?
> ACPI spec does not describe what happens on load failure.
> For linux it does not matter much -
> it just handles the error. What happens on windows with an unresolved
> reference? Is failure to load the object any better?
I was thinking more in a align of assigning a new temporary package value to
a statically named CCST:

  update_cst_METHOD()
     build package in local0
     \SB.CPUS.CCST = local0

so guest gets valid initial CCST with values on source host at boot time
and on target values are replaced on update.

It doesn't have to be named variable/could be a method but with always
valid values.

> 
> > > +                aml_append(dev, method);
> > > +            }
> > >              aml_append(cpus_dev, dev);
> > >          }
> > >      }
> > > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> > > index fff1059a31..da2c830db7 100644
> > > --- a/hw/i386/acpi-build.c
> > > +++ b/hw/i386/acpi-build.c
> > > @@ -64,6 +64,7 @@
> > >  #include "hw/i386/intel_iommu.h"
> > >  
> > >  #include "hw/acpi/ipmi.h"
> > > +#include "hw/acpi/cst.h"
> > >  
> > >  /* These are used to size the ACPI tables for -M pc-i440fx-1.7 and
> > >   * -M pc-i440fx-2.0.  Even if the actual amount of AML generated grows
> > > @@ -1840,7 +1841,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
> > >          build_legacy_cpu_hotplug_aml(dsdt, machine, pm->cpu_hp_io_base);
> > >      } else {
> > >          CPUHotplugFeatures opts = {
> > > -            .apci_1_compatible = true, .has_legacy_cphp = true
> > > +            .apci_1_compatible = true, .has_legacy_cphp = true,  
> > unrelated change???  
> 
> Good catch.
> 
> > >          };
> > >          build_cpus_aml(dsdt, machine, opts, pm->cpu_hp_io_base,
> > >                         "\\_SB.PCI0", "\\_GPE._E02");
> > > @@ -2693,6 +2694,10 @@ void acpi_build(AcpiBuildTables *tables, MachineState *machine)
> > >                             tables->vmgenid, tables->linker);
> > >      }
> > >  
> > > +    /* TODO: get a free ioport. This one is PIIX specific. */
> > > +    acpi_add_table(table_offsets, tables_blob);
> > > +    cst_build_acpi(tables_blob, tables->linker, 0xaf20);
> > > +
> > >      if (misc.has_hpet) {
> > >          acpi_add_table(table_offsets, tables_blob);
> > >          build_hpet(tables_blob, tables->linker);
> > > @@ -2891,6 +2896,9 @@ void acpi_setup(void)
> > >  
> > >      build_state = g_malloc0(sizeof *build_state);
> > >  
> > > +    /* TODO: this is not the best place to do it */
> > > +    cst_register(pcms->fw_cfg, 0xaf20);
> > > +
> > >      acpi_build_tables_init(&tables);
> > >      acpi_build(&tables, MACHINE(pcms));
> > >