Re: [Qemu-devel] [PATCH RFC 6/7] hw/acpi: extend acpi pci hotplug support for pci express

[Igor Mammedov]

On Tue, 21 Jun 2016 12:05:12 +0300
Marcel Apfelbaum <address@hidden> wrote:

> On 06/20/2016 05:11 PM, Igor Mammedov wrote:
> > On Tue, 31 May 2016 20:48:37 +0300
> > Marcel Apfelbaum <address@hidden> wrote:
> >
> > subj doesn't match patch, it does opposite i.e. makes sure that
> > pcie isn't counted in when building acpi hotplug aml
> >
> 
> Maybe I wasn't clear enough. Until now q35 had no acpi hotplug code.
> This patch adds acpi hotplug code for all Q35 PCI buses, but no for
> pcie buses That means for pci-pci bridge and dmi-pci bridge.
> 
> 
> Maybe I should rename it to hw/acpi: extend acpi pci hotplug support
> for Q35 pci buses.
this looks better to me

> 
> >> Emit acpi code for pci hotplug on all PC machines:
> >>   - if legacy pci hotpug is enabled (pcihp_bridge_en)
> >>   - if there is at least one legacy pci bridge in current system
> >>   - for PCI buses only (skip PCIe buses)
> >>
> >> Signed-off-by: Marcel Apfelbaum <address@hidden>
> >> ---
> >>   hw/i386/acpi-build.c | 49
> >> ++++++++++++++++++++++++++++++++----------------- 1 file changed,
> >> 32 insertions(+), 17 deletions(-)
> >>
> >> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> >> index 8ae3e53..cc51f9e 100644
> >> --- a/hw/i386/acpi-build.c
> >> +++ b/hw/i386/acpi-build.c
> >> @@ -250,6 +250,11 @@ static void acpi_get_pci_info(PcPciInfo *info)
> >>                                               NULL);
> >>   }
> >>
> >> +static void acpi_test_pci_bus(PCIBus *bus, void *opaque)
> >> +{
> >> +    *(bool *)opaque |= !pci_bus_is_express(bus);
> >> +}
> >> +
> >>   #define ACPI_PORT_SMI_CMD           0x00b2 /* TODO: this is
> >> APM_CNT_IOPORT */
> >>   static void acpi_align_size(GArray *blob, unsigned align)
> >> @@ -422,7 +427,7 @@ static void *acpi_set_bsel(PCIBus *bus, void
> >> *opaque) unsigned *bsel_alloc = opaque;
> >>       unsigned *bus_bsel;
> >>
> >> -    if (qbus_is_hotpluggable(BUS(bus))) {
> >> +    if (qbus_is_hotpluggable(BUS(bus))
> >> && !pci_bus_is_express(bus)) { bus_bsel = g_malloc(sizeof
> >> *bus_bsel);
> >>
> >>           *bus_bsel = (*bsel_alloc)++;
> >> @@ -433,15 +438,12 @@ static void *acpi_set_bsel(PCIBus *bus, void
> >> *opaque) return bsel_alloc;
> >>   }
> >>
> >> -static void acpi_set_pci_info(void)
> >> +static void acpi_set_pci_info(PCIBus *bus)
> >>   {
> >> -    PCIBus *bus = find_i440fx(); /* TODO: Q35 support */
> >>       unsigned bsel_alloc = 0;
> >>
> >> -    if (bus) {
> >> -        /* Scan all PCI buses. Set property to enable acpi based
> >> hotplug. */
> >> -        pci_for_each_bus_depth_first(bus, acpi_set_bsel, NULL,
> >> &bsel_alloc);
> >> -    }
> >> +    /* Scan all PCI buses. Set property to enable acpi based
> >> hotplug. */
> >> +    pci_for_each_bus_depth_first(bus, acpi_set_bsel, NULL,
> >> &bsel_alloc); }
> >>
> >>   static void build_append_pcihp_notify_entry(Aml *method, int
> >> slot) @@ -503,7 +505,7 @@ static void
> >> build_append_pci_bus_devices(Aml *parent_scope, PCIBus *bus,
> >>            * In this case they aren't themselves hot-pluggable.
> >>            * Hotplugged bridges *are* hot-pluggable.
> >>            */
> >> -        bridge_in_acpi = pc->is_bridge && pcihp_bridge_en &&
> >> +        bridge_in_acpi = pc->is_bridge && !pc->is_express &&
> >> pcihp_bridge_en && !DEVICE(pdev)->hotplugged;
> >>
> >>           hotplug_enabled_dev = bsel && dc->hotpluggable
> >> && !bridge_in_acpi; @@ -1892,7 +1894,7 @@ static void
> >> build_piix4_isa_bridge(Aml *table) aml_append(table, scope);
> >>   }
> >>
> >> -static void build_piix4_pci_hotplug(Aml *table)
> >> +static void build_acpi_pci_hotplug(Aml *table)
> >>   {
> >>       Aml *scope;
> >>       Aml *field;
> >> @@ -1995,6 +1997,7 @@ build_dsdt(GArray *table_data, GArray
> >> *linker, uint32_t nr_mem = machine->ram_slots;
> >>       int root_bus_limit = 0xFF;
> >>       PCIBus *root_bus = NULL;
> >> +    bool has_pci_bus = false;
> >>       int i;
> >>
> >>       dsdt = init_aml_allocator();
> >> @@ -2016,7 +2019,6 @@ build_dsdt(GArray *table_data, GArray
> >> *linker, build_piix4_pm(dsdt);
> >>           build_piix4_isa_bridge(dsdt);
> >>           build_isa_devices_aml(dsdt);
> >> -        build_piix4_pci_hotplug(dsdt);
> >>           build_piix4_pci0_int(dsdt);
> >>       } else {
> >>           sb_scope = aml_scope("_SB");
> >> @@ -2040,6 +2042,11 @@ build_dsdt(GArray *table_data, GArray
> >> *linker, root_bus = PC_MACHINE(machine)->bus;
> >>       assert(root_bus);
> >>
> >> +    pci_for_each_bus(root_bus, acpi_test_pci_bus, &has_pci_bus);
> >> +    if (pm->pcihp_bridge_en && has_pci_bus) {
> >             ^^^^^ wouldn't that forbid acpi hotplug on PCI0 is it's
> > not set?
> 
> Yes, and this is by design. 'pcihp_bridge_en' flag matches 'acpi
> hotplug'. I followed the initialization phase, am I wrong? Can you
> have acpi hotplug if the bit is off?
my understanding was that pcihp_bridge_en governs only hotplug
AML for bridges, while with it disabled hotplug AML would be
generated only for PCI0.

> >
> >> +        build_acpi_pci_hotplug(dsdt);
> >> +    }
> >> +
> >>       build_cpu_hotplug_aml(dsdt);
> >>       build_memory_hotplug_aml(dsdt, nr_mem, pm->mem_hp_io_base,
> >>                                pm->mem_hp_io_len);
> >> @@ -2050,7 +2057,7 @@ build_dsdt(GArray *table_data, GArray
> >> *linker,
> >>
> >>           aml_append(scope, aml_method("_L00", 0,
> >> AML_NOTSERIALIZED));
> >>
> >> -        if (misc->is_piix4) {
> >> +        if (pm->pcihp_bridge_en && has_pci_bus) {
> > same question as above
> >
> >>               method = aml_method("_E01", 0, AML_NOTSERIALIZED);
> >>               aml_append(method,
> >>                   aml_acquire(aml_name("\\_SB.PCI0.BLCK"),
> >> 0xFFFF)); @@ -2188,7 +2195,7 @@ build_dsdt(GArray *table_data,
> >> GArray *linker, g_ptr_array_free(mem_ranges, true);
> >>
> >>       /* reserve PCIHP resources */
> >> -    if (pm->pcihp_io_len) {
> >> +    if (pm->pcihp_bridge_en && has_pci_bus && pm->pcihp_io_len) {
> > same question as above
> >
> >>           dev = aml_device("PHPR");
> >>           aml_append(dev, aml_name_decl("_HID",
> >> aml_string("PNP0A06"))); aml_append(dev,
> >> @@ -2326,10 +2333,14 @@ build_dsdt(GArray *table_data, GArray
> >> *linker,
> >>
> >>           {
> >>               Aml *scope = aml_scope("PCI0");
> >> +            bool scope_used = false;
> > Could you explain why ^^^ is needed?
> >
> 
> Sure. If none ACPI code will be generated by the below 'if' statements
> we will have an empty PCI0 scope. I wanted to get rid of it.
considering that hotplug AML for PCI0 is always generated, that seems
useless.

> 
> 
> Thanks,
> Marcel
> 
> >>
> >> -            /* Scan all PCI buses. Generate tables to support
> >> hotplug. */
> >> -            build_append_pci_bus_devices(scope, root_bus,
> >> -                                         pm->pcihp_bridge_en);
> >> +            if (pm->pcihp_bridge_en && has_pci_bus) {
> >> +                /* Scan all PCI buses. Generate tables to support
> >> hotplug. */
> >> +                build_append_pci_bus_devices(scope, root_bus,
> >> +                                             pm->pcihp_bridge_en);
> >> +                scope_used = true;
> >> +            }
> >>
> >>               if (misc->tpm_version != TPM_VERSION_UNSPEC) {
> >>                   dev = aml_device("ISA.TPM");
> >> @@ -2346,8 +2357,12 @@ build_dsdt(GArray *table_data, GArray
> >> *linker, /* aml_append(crs, aml_irq_no_flags(TPM_TIS_IRQ)); */
> >>                   aml_append(dev, aml_name_decl("_CRS", crs));
> >>                   aml_append(scope, dev);
> >> +                scope_used = true;
> >> +            }
> >> +
> >> +            if (scope_used) {
> >> +                aml_append(sb_scope, scope);
> >>               }
> >> -            aml_append(sb_scope, scope);
> >>           }
> >>           aml_append(dsdt, sb_scope);
> >>       }
> >> @@ -2870,7 +2885,7 @@ void acpi_setup(void)
> >>
> >>       build_state = g_malloc0(sizeof *build_state);
> >>
> >> -    acpi_set_pci_info();
> >> +    acpi_set_pci_info(pcms->bus);
> >>
> >>       acpi_build_tables_init(&tables);
> >>       acpi_build(&tables, MACHINE(pcms));
> >
>