Re: [Qemu-devel] [PATCH v2 09/11] vfio: vote a device to do host bus reset

[Michael S. Tsirkin]

On Mon, Mar 07, 2016 at 11:23:02AM +0800, Cao jin wrote:
> From: Chen Fan <address@hidden>
> 
> Signed-off-by: Chen Fan <address@hidden>
> ---
>  hw/vfio/pci.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  hw/vfio/pci.h |  1 +
>  2 files changed, 58 insertions(+)
> 
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 24848c9..8e902d2 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -1937,6 +1937,8 @@ static void vfio_check_host_bus_reset(VFIOPCIDevice 
> *vdev, Error **errp)
>      /* List all affected devices by bus reset */
>      devices = &info->devices[0];
>  
> +    vdev->single_depend_dev = (info->count == 1);
> +
>      /* Verify that we have all the groups required */
>      for (i = 0; i < info->count; i++) {
>          PCIHostDeviceAddress host;
> @@ -2998,6 +3000,49 @@ static void vfio_exitfn(PCIDevice *pdev)
>      vfio_unregister_bars(vdev);
>  }
>  
> +static VFIOPCIDevice *vfio_pci_get_do_reset_device(VFIOPCIDevice *vdev)
> +{
> +    struct vfio_pci_hot_reset_info *info = NULL;
> +    struct vfio_pci_dependent_device *devices;
> +    VFIOGroup *group;
> +    VFIODevice *vbasedev_iter;
> +    int ret;
> +
> +    ret = vfio_get_hot_reset_info(vdev, &info);
> +    if (ret) {
> +        error_report("vfio: Cannot enable AER for device %s,"
> +                     " device does not support hot reset.",
> +                     vdev->vbasedev.name);
> +        return NULL;
> +    }
> +
> +    devices = &info->devices[0];
> +
> +    QLIST_FOREACH(group, &vfio_group_list, next) {
> +        if (group->groupid == devices[0].group_id) {
> +            break;
> +        }
> +    }
> +
> +    if (!group) {
> +        error_report("vfio: Cannot enable AER for device %s, "
> +                    "depends on group %d which is not owned.",
> +                    vdev->vbasedev.name, devices[0].group_id);
> +        return NULL;
> +    }
> +
> +    QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
> +        if (vbasedev_iter->type != VFIO_DEVICE_TYPE_PCI ||
> +            !(vdev->features & VFIO_FEATURE_ENABLE_AER)) {
> +            continue;
> +        }
> +
> +        return container_of(vbasedev_iter, VFIOPCIDevice, vbasedev);
> +    }
> +
> +    return NULL;
> +}
> +
>  static void vfio_pci_reset(DeviceState *dev)
>  {
>      PCIDevice *pdev = DO_UPCAST(PCIDevice, qdev, dev);
> @@ -3005,6 +3050,18 @@ static void vfio_pci_reset(DeviceState *dev)
>  
>      trace_vfio_pci_reset(vdev->vbasedev.name);
>  
> +    if (pdev->bus->in_hot_reset) {

After discussing this with Alex, I think what you
really are looking for is
     if (dev->realized)
in order to skip hot reset when device is plugged-in
initially.


> +        VFIOPCIDevice *tmp;
> +
> +        tmp = vfio_pci_get_do_reset_device(vdev);
> +        if (tmp) {
> +            if (tmp == vdev) {
> +                vfio_pci_hot_reset(vdev, vdev->single_depend_dev);
> +            }
> +            return;
> +        }
> +    }
> +
>      vfio_pci_pre_reset(vdev);
>  
>      if (vdev->resetfn && !vdev->resetfn(vdev)) {
> diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
> index aff46c2..32bd31f 100644
> --- a/hw/vfio/pci.h
> +++ b/hw/vfio/pci.h
> @@ -143,6 +143,7 @@ typedef struct VFIOPCIDevice {
>      bool no_kvm_intx;
>      bool no_kvm_msi;
>      bool no_kvm_msix;
> +    bool single_depend_dev;
>  } VFIOPCIDevice;
>  
>  uint32_t vfio_pci_read_config(PCIDevice *pdev, uint32_t addr, int len);
> -- 
> 1.9.3
> 
>