[RFC,v7,03/11] qdev: add bus reset_notifiers callbacks for host bus reset

Particularly, For vfio device, Once need to recovery devices
by bus reset such as AER, we always need to reset the host bus
to recovery the devices under the bus, so we need to add pci bus
callbacks to specify to do host bus reset.

Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
---
 hw/pci/pci.c                  |  6 ++++++
 hw/pci/pci_bridge.c           |  3 +++
 hw/vfio/pci.c                 | 12 ++++++++++++
 include/hw/pci/pci.h          |  2 ++
 include/hw/pci/pci_bus.h      |  2 ++
 include/hw/vfio/vfio-common.h |  1 +
 6 files changed, 26 insertions(+)

On Tue, 2015-05-19 at 12:42 +0800, Chen Fan wrote:
> Particularly, For vfio device, Once need to recovery devices
> by bus reset such as AER, we always need to reset the host bus
> to recovery the devices under the bus, so we need to add pci bus
> callbacks to specify to do host bus reset.
> 
> Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> ---
>  hw/pci/pci.c                  |  6 ++++++
>  hw/pci/pci_bridge.c           |  3 +++
>  hw/vfio/pci.c                 | 12 ++++++++++++
>  include/hw/pci/pci.h          |  2 ++
>  include/hw/pci/pci_bus.h      |  2 ++
>  include/hw/vfio/vfio-common.h |  1 +
>  6 files changed, 26 insertions(+)
> 
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 48f19a3..cac7769 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -74,11 +74,17 @@ static const VMStateDescription vmstate_pcibus = {
>      }
>  };
>  
> +void pci_bus_add_reset_notifier(PCIBus *bus, Notifier *notify)
> +{
> +    notifier_list_add(&bus->reset_notifiers, notify);
> +}
> +

How do we support hot-unplug without a matching remove function?

>  static void pci_bus_realize(BusState *qbus, Error **errp)
>  {
>      PCIBus *bus = PCI_BUS(qbus);
>  
>      vmstate_register(NULL, -1, &vmstate_pcibus, bus);
> +    notifier_list_init(&bus->reset_notifiers);
>  }
>  
>  static void pci_bus_unrealize(BusState *qbus, Error **errp)
> diff --git a/hw/pci/pci_bridge.c b/hw/pci/pci_bridge.c
> index 40c97b1..88c3240 100644
> --- a/hw/pci/pci_bridge.c
> +++ b/hw/pci/pci_bridge.c
> @@ -267,6 +267,9 @@ void pci_bridge_write_config(PCIDevice *d,
>  
>      newctl = pci_get_word(d->config + PCI_BRIDGE_CONTROL);
>      if (~oldctl & newctl & PCI_BRIDGE_CTL_BUS_RESET) {
> +        /* Particularly for vfio devices to reset host bus */
> +        notifier_list_notify(&s->sec_bus.reset_notifiers, NULL);
> +
>          /* Trigger hot reset on 0->1 transition. */
>          qbus_reset_all(&s->sec_bus.qbus);
>      }
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c

vfio changes should be done in a separate patch, the QEMU PCI-core
changes would need to be ack'd by mst.

> index 037a2c6..43869e9 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -154,6 +154,7 @@ typedef struct VFIOPCIDevice {
>      PCIHostDeviceAddress host;
>      EventNotifier err_notifier;
>      EventNotifier req_notifier;
> +    Notifier sec_bus_reset_notifier;
>      int (*resetfn)(struct VFIOPCIDevice *);
>      uint32_t features;
>  #define VFIO_FEATURE_ENABLE_VGA_BIT 0
> @@ -3524,6 +3525,14 @@ static void vfio_setup_resetfn(VFIOPCIDevice *vdev)
>      }
>  }
>  
> +static void vfio_pci_host_needs_bus_reset(Notifier *n, void *opaque)
> +{
> +    VFIOPCIDevice *vdev = container_of(n, VFIOPCIDevice, sec_bus_reset_notifier);
> +    VFIODevice *vbasedev = &vdev->vbasedev;
> +
> +    vbasedev->needs_bus_reset = true;
> +}
> +
>  static int vfio_initfn(PCIDevice *pdev)
>  {
>      VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
> @@ -3674,6 +3683,9 @@ static int vfio_initfn(PCIDevice *pdev)
>      vfio_register_req_notifier(vdev);
>      vfio_setup_resetfn(vdev);
>  
> +    vdev->sec_bus_reset_notifier.notify = vfio_pci_host_needs_bus_reset;
> +    pci_bus_add_reset_notifier(pdev->bus, &vdev->sec_bus_reset_notifier);
> +

The notifier obviously needs to be unregistered in the exitfn.

>      return 0;
>  
>  out_teardown:
> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> index 5d050c8..eae236a 100644
> --- a/include/hw/pci/pci.h
> +++ b/include/hw/pci/pci.h
> @@ -7,6 +7,7 @@
>  #include "exec/memory.h"
>  #include "sysemu/dma.h"
>  #include "qapi/error.h"
> +#include "qemu/notify.h"
>  
>  /* PCI includes legacy ISA access.  */
>  #include "hw/isa/isa.h"
> @@ -371,6 +372,7 @@ void pci_bus_fire_intx_routing_notifier(PCIBus *bus);
>  void pci_device_set_intx_routing_notifier(PCIDevice *dev,
>                                            PCIINTxRoutingNotifier notifier);
>  void pci_device_reset(PCIDevice *dev);
> +void pci_bus_add_reset_notifier(PCIBus *bus, Notifier *notify);
>  
>  PCIDevice *pci_nic_init_nofail(NICInfo *nd, PCIBus *rootbus,
>                                 const char *default_model,
> diff --git a/include/hw/pci/pci_bus.h b/include/hw/pci/pci_bus.h
> index fabaeee..3b551d7 100644
> --- a/include/hw/pci/pci_bus.h
> +++ b/include/hw/pci/pci_bus.h
> @@ -29,6 +29,8 @@ struct PCIBus {
>         Keep a count of the number of devices with raised IRQs.  */
>      int nirq;
>      int *irq_count;
> +
> +    NotifierList reset_notifiers;
>  };
>  
>  typedef struct PCIBridgeWindows PCIBridgeWindows;
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index 0d1fb80..5f5691a 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -102,6 +102,7 @@ typedef struct VFIODevice {
>      bool reset_works;
>      bool needs_reset;
>      bool allow_mmap;
> +    bool needs_bus_reset;

This is PCI specific, it should be added to VFIOPCIDevice only.

>      VFIODeviceOps *ops;
>      unsigned int num_irqs;
>      unsigned int num_regions;