Re: [Qemu-devel] [RFC v10 13/19] pci: add bus reset_notifiers callbacks for host bus reset

[Michael S. Tsirkin]

On Tue, Jun 16, 2015 at 04:10:57PM +0800, Chen Fan wrote:
> Particularly, For vfio devices, 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 <address@hidden>

Interesting. What prevents guest from triggering reset at an arbitrary
time, killing all VFs for all guests?

> ---
>  hw/pci/pci.c             | 16 ++++++++++++++++
>  hw/pci/pci_bridge.c      |  6 ++++++
>  include/hw/pci/pci.h     |  4 ++++
>  include/hw/pci/pci_bus.h |  2 ++
>  4 files changed, 28 insertions(+)
> 
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 3423c3a..3bd954e 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -74,11 +74,27 @@ static const VMStateDescription vmstate_pcibus = {
>      }
>  };
>  
> +void pci_bus_add_reset_notifier(PCIBus *bus, Notifier *notify)
> +{
> +    notifier_list_add(&bus->reset_notifiers, notify);
> +}
> +
> +void pci_bus_remove_reset_notifier(Notifier *notify)
> +{
> +    notifier_remove(notify);
> +}
> +
> +void pci_bus_run_reset_notifier(PCIBus *bus, void *opaque)
> +{
> +    notifier_list_notify(&bus->reset_notifiers, opaque);
> +}
> +
>  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..a8e3f57 100644
> --- a/hw/pci/pci_bridge.c
> +++ b/hw/pci/pci_bridge.c
> @@ -267,6 +267,12 @@ void pci_bridge_write_config(PCIDevice *d,
>  
>      newctl = pci_get_word(d->config + PCI_BRIDGE_CONTROL);
>      if (~oldctl & newctl & PCI_BRIDGE_CTL_BUS_RESET) {
> +        /*
> +         * Notify all vfio-pci devices under the bus
> +         * to do physical bus reset.
> +         */
> +        pci_for_each_bus(&s->sec_bus,
> +                pci_bus_run_reset_notifier, d);
>          /* Trigger hot reset on 0->1 transition. */
>          qbus_reset_all(&s->sec_bus.qbus);
>      }
> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> index 6c2af0d..d353c9d 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"
> @@ -377,6 +378,9 @@ 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);
> +void pci_bus_remove_reset_notifier(Notifier *notify);
> +void pci_bus_run_reset_notifier(PCIBus *bus, void *opaque);
>  
>  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;
> -- 
> 1.9.3
>