Re: [Qemu-devel] [RFC v8.1 09/13] vfio: add sec_bus_reset notifier to notify physical bus reset is needed

[Alex Williamson <alex.williamson@redhat.com>]

On Wed, 2015-05-27 at 10:46 +0800, Chen Fan wrote:
> Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> ---
>  hw/vfio/pci.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 91ad9ad..a8c5988 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -156,6 +156,7 @@ 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
> @@ -172,6 +173,7 @@ typedef struct VFIOPCIDevice {
>      bool has_flr;
>      bool has_pm_reset;
>      bool has_bus_reset;
> +    bool needs_bus_reset;
>      bool rom_read_failed;
>  } VFIOPCIDevice;
>  
> @@ -3828,6 +3830,17 @@ static Notifier machine_notifier = {
>      .notify = vfio_pci_machine_done_notify,
>  };
>  
> +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;
> +
> +    if (vdev->has_bus_reset) {
> +        vdev->needs_bus_reset = true;
> +        vbasedev->needs_reset = true;

We really can't trust has_bus_reset, so this could really just be
features & AER, which then begs the question why we register a notifier
for devices that don't support the AER feature.

> +    }
> +}
> +
>  static int vfio_initfn(PCIDevice *pdev)
>  {
>      VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
> @@ -3978,6 +3991,9 @@ 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);
> +
>      return 0;
>  
>  out_teardown:
> @@ -4006,6 +4022,7 @@ static void vfio_exitfn(PCIDevice *pdev)
>  
>      vfio_unregister_req_notifier(vdev);
>      vfio_unregister_err_notifier(vdev);
> +    pci_bus_remove_reset_notifier(&vdev->sec_bus_reset_notifier);
>      pci_device_set_intx_routing_notifier(&vdev->pdev, NULL);
>      vfio_disable_interrupts(vdev);
>      if (vdev->intx.mmap_timer) {