Re: [Qemu-devel] [PATCH v2 06/10] pci/pcihp: overwrite hotplug handler recursively from the start

[Igor Mammedov <imammedo@redhat.com>]

On Mon,  5 Nov 2018 11:20:40 +0100
David Hildenbrand <david@redhat.com> wrote:

> For now, the hotplug handler is not called for devices that are
> being cold plugged. The hotplug handler is setup when the machine
> initialization is fully done. Only bridges that were cold plugged are
> considered.
> 
> Set the hotplug handler for the root piix bus directly when realizing.
> Overwrite the hotplug handler of bridges when coldplugging them.
> 
> This will now make sure that the ACPI PCI hotplug handler is also called
> for cold plugged devices (also on bridges) but not for bridges that were
> hotplugged (keeping the current behavior).
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>

Reviewed-by: Igor Mammedov <imammedo@redhat.com>

> ---
>  hw/acpi/pcihp.c | 15 +++++++++++++++
>  hw/acpi/piix4.c | 16 +---------------
>  2 files changed, 16 insertions(+), 15 deletions(-)
> 
> diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
> index 5e7cef173c..05e3f8d11e 100644
> --- a/hw/acpi/pcihp.c
> +++ b/hw/acpi/pcihp.c
> @@ -30,6 +30,7 @@
>  #include "hw/hw.h"
>  #include "hw/i386/pc.h"
>  #include "hw/pci/pci.h"
> +#include "hw/pci/pci_bridge.h"
>  #include "hw/acpi/acpi.h"
>  #include "sysemu/sysemu.h"
>  #include "exec/address-spaces.h"
> @@ -240,6 +241,20 @@ void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s,
>       * it is present on boot, no hotplug event is necessary. We do send an
>       * event when the device is disabled later. */
>      if (!dev->hotplugged) {
> +        /*
> +         * Overwrite the default hotplug handler with the ACPI PCI one
> +         * for cold plugged bridges only.
> +         */
> +        if (!s->legacy_piix &&
> +            object_dynamic_cast(OBJECT(dev), TYPE_PCI_BRIDGE)) {
> +            PCIBus *sec = pci_bridge_get_sec_bus(PCI_BRIDGE(pdev));
> +
> +            qbus_set_hotplug_handler(BUS(sec), DEVICE(hotplug_dev),
> +                                     &error_abort);
> +            /* We don't have to overwrite any other hotplug handler yet */
> +            assert(QLIST_EMPTY(&sec->child));
> +        }
> +
>          return;
>      }
>  
> diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
> index e586cfdc53..160f727a5e 100644
> --- a/hw/acpi/piix4.c
> +++ b/hw/acpi/piix4.c
> @@ -446,15 +446,6 @@ static void piix4_device_unplug_cb(HotplugHandler *hotplug_dev,
>      }
>  }
>  
> -static void piix4_update_bus_hotplug(PCIBus *pci_bus, void *opaque)
> -{
> -    PIIX4PMState *s = opaque;
> -
> -    /* pci_bus cannot outlive PIIX4PMState, because /machine keeps it alive
> -     * and it's not hot-unpluggable */
> -    qbus_set_hotplug_handler(BUS(pci_bus), DEVICE(s), &error_abort);
> -}
> -
>  static void piix4_pm_machine_ready(Notifier *n, void *opaque)
>  {
>      PIIX4PMState *s = container_of(n, PIIX4PMState, machine_ready);
> @@ -468,12 +459,6 @@ static void piix4_pm_machine_ready(Notifier *n, void *opaque)
>      pci_conf[0x63] = 0x60;
>      pci_conf[0x67] = (memory_region_present(io_as, 0x3f8) ? 0x08 : 0) |
>          (memory_region_present(io_as, 0x2f8) ? 0x90 : 0);
> -
> -    if (s->use_acpi_pci_hotplug) {
> -        pci_for_each_bus(pci_get_bus(d), piix4_update_bus_hotplug, s);
> -    } else {
> -        piix4_update_bus_hotplug(pci_get_bus(d), s);
> -    }
>  }
>  
>  static void piix4_pm_add_propeties(PIIX4PMState *s)
> @@ -547,6 +532,7 @@ static void piix4_pm_realize(PCIDevice *dev, Error **errp)
>  
>      piix4_acpi_system_hot_add_init(pci_address_space_io(dev),
>                                     pci_get_bus(dev), s);
> +    qbus_set_hotplug_handler(BUS(pci_get_bus(dev)), DEVICE(s), &error_abort);
>  
>      piix4_pm_add_propeties(s);
>  }