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

[Marcel Apfelbaum <marcel@redhat.com>]

On 06/20/2016 05:11 PM, Igor Mammedov wrote:
> On Tue, 31 May 2016 20:48:37 +0300
> Marcel Apfelbaum <marcel@redhat.com> 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.

>> 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 <marcel@redhat.com>
>> ---
>>   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?

>
>> +        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.


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));
>