Re: [PATCH v3 17/29] hw/arm/virt-acpi-build: Modify the DSDT ACPI table to enable ACPI PCI hotplug

[Igor Mammedov <imammedo@redhat.com>]

On Fri, 20 Jun 2025 10:35:38 +0100
Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote:

> On Mon, 16 Jun 2025 11:46:46 +0200
> Eric Auger <eric.auger@redhat.com> wrote:
> 
> > Modify the DSDT ACPI table to enable ACPI PCI hotplug.
> > 
> > Signed-off-by: Eric Auger <eric.auger@redhat.com>
> > 
> > ---
> > v2 -> v3:
> > - use ACPI_PCIHP_SIZE instead of 0x1000 (Igor)
> > - use cihp_state->use_acpi_hotplug_bridge  
> 
> pcihp_state
> 
> Takes a bit of searching to find the various bits of the
> same support on x86 but this seems to match up.
> Exactly when things are built does vary but not I think
> in a way that matters.  e.g. I think on x86 the
> EDSM stuff is built whether or not we have pcihp enabled
> whereas here you've made it conditional on using acpi
> hp.  Perhaps a tiny bit more description on that would be
> useful if you do a v4?

edsm should be built regardless of pcihp
(well intention was there, whether I messed it up or not I don't know)

idea is that non hotplug ports can have a static acpi-index,
so it doesn't depend on pcihp.

> 
> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
> 
> 
> > ---
> >  include/hw/acpi/pcihp.h  |  2 ++
> >  include/hw/arm/virt.h    |  1 +
> >  hw/arm/virt-acpi-build.c | 22 ++++++++++++++++++++++
> >  hw/arm/virt.c            |  2 ++
> >  hw/arm/Kconfig           |  2 ++
> >  5 files changed, 29 insertions(+)
> > 
> > diff --git a/include/hw/acpi/pcihp.h b/include/hw/acpi/pcihp.h
> > index 5506a58862..9ff548650b 100644
> > --- a/include/hw/acpi/pcihp.h
> > +++ b/include/hw/acpi/pcihp.h
> > @@ -38,6 +38,8 @@
> >  #define ACPI_PCIHP_SEJ_BASE 0x8
> >  #define ACPI_PCIHP_BNMR_BASE 0x10
> >  
> > +#define ACPI_PCIHP_SIZE 0x0018
> > +
> >  typedef struct AcpiPciHpPciStatus {
> >      uint32_t up;
> >      uint32_t down;
> > diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
> > index 9a1b0f53d2..0ed2e6b732 100644
> > --- a/include/hw/arm/virt.h
> > +++ b/include/hw/arm/virt.h
> > @@ -79,6 +79,7 @@ enum {
> >      VIRT_ACPI_GED,
> >      VIRT_NVDIMM_ACPI,
> >      VIRT_PVTIME,
> > +    VIRT_ACPI_PCIHP,
> >      VIRT_LOWMEMMAP_LAST,
> >  };
> >  
> > diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> > index d7547c8d3b..a2e58288f8 100644
> > --- a/hw/arm/virt-acpi-build.c
> > +++ b/hw/arm/virt-acpi-build.c
> > @@ -34,6 +34,7 @@
> >  #include "hw/core/cpu.h"
> >  #include "hw/acpi/acpi-defs.h"
> >  #include "hw/acpi/acpi.h"
> > +#include "hw/acpi/pcihp.h"
> >  #include "hw/nvram/fw_cfg_acpi.h"
> >  #include "hw/acpi/bios-linker-loader.h"
> >  #include "hw/acpi/aml-build.h"
> > @@ -809,6 +810,8 @@ static void
> >  build_dsdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
> >  {
> >      VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(vms);
> > +    AcpiGedState *acpi_ged_state = ACPI_GED(vms->acpi_dev);
> > +    AcpiPciHpState *pcihp_state = &acpi_ged_state->pcihp_state;
> >      Aml *scope, *dsdt;
> >      MachineState *ms = MACHINE(vms);
> >      const MemMapEntry *memmap = vms->memmap;
> > @@ -868,6 +871,25 @@ build_dsdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
> >  
> >      aml_append(dsdt, scope);
> >  
> > +    if (pcihp_state->use_acpi_hotplug_bridge) {
> > +        Aml *pci0_scope = aml_scope("\\_SB.PCI0");
> > +
> > +        aml_append(pci0_scope, aml_pci_edsm());
> > +        build_acpi_pci_hotplug(dsdt, AML_SYSTEM_MEMORY,
> > +                               memmap[VIRT_ACPI_PCIHP].base);
> > +        build_append_pcihp_resources(pci0_scope,
> > +                                     memmap[VIRT_ACPI_PCIHP].base,
> > +                                     memmap[VIRT_ACPI_PCIHP].size);
> > +
> > +        /* Scan all PCI buses. Generate tables to support hotplug. */
> > +        build_append_pci_bus_devices(pci0_scope, vms->bus);
> > +        if (object_property_find(OBJECT(vms->bus), ACPI_PCIHP_PROP_BSEL)) {
> > +            build_append_pcihp_slots(pci0_scope, vms->bus);
> > +        }
> > +        build_append_notification_callback(pci0_scope, vms->bus);
> > +        aml_append(dsdt, pci0_scope);
> > +    }
> > +
> >      /* copy AML table into ACPI tables blob */
> >      g_array_append_vals(table_data, dsdt->buf->data, dsdt->buf->len);
> >    
>