Re: [PATCH v9 17/21] vfio-pci/zdev: add open/close device hooks

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

On Mon,  6 Jun 2022 16:33:21 -0400
Matthew Rosato <mjrosato@linux.ibm.com> wrote:

> During vfio-pci open_device, pass the KVM associated with the vfio group
> (if one exists).  This is needed in order to pass a special indicator
> (GISA) to firmware to allow zPCI interpretation facilities to be used
> for only the specific KVM associated with the vfio-pci device.  During
> vfio-pci close_device, unregister the notifier.
> 
> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
> ---
>  drivers/vfio/pci/vfio_pci_core.c | 10 +++++++++-
>  drivers/vfio/pci/vfio_pci_zdev.c | 24 ++++++++++++++++++++++++
>  include/linux/vfio_pci_core.h    | 10 ++++++++++
>  3 files changed, 43 insertions(+), 1 deletion(-)


Acked-by: Alex Williamson <alex.williamson@redhat.com>


> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index a0d69ddaf90d..b1e5cfbadf38 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -316,10 +316,14 @@ int vfio_pci_core_enable(struct vfio_pci_core_device *vdev)
>  		pci_write_config_word(pdev, PCI_COMMAND, cmd);
>  	}
>  
> -	ret = vfio_config_init(vdev);
> +	ret = vfio_pci_zdev_open_device(vdev);
>  	if (ret)
>  		goto out_free_state;
>  
> +	ret = vfio_config_init(vdev);
> +	if (ret)
> +		goto out_free_zdev;
> +
>  	msix_pos = pdev->msix_cap;
>  	if (msix_pos) {
>  		u16 flags;
> @@ -340,6 +344,8 @@ int vfio_pci_core_enable(struct vfio_pci_core_device *vdev)
>  
>  	return 0;
>  
> +out_free_zdev:
> +	vfio_pci_zdev_close_device(vdev);
>  out_free_state:
>  	kfree(vdev->pci_saved_state);
>  	vdev->pci_saved_state = NULL;
> @@ -418,6 +424,8 @@ void vfio_pci_core_disable(struct vfio_pci_core_device *vdev)
>  
>  	vdev->needs_reset = true;
>  
> +	vfio_pci_zdev_close_device(vdev);
> +
>  	/*
>  	 * If we have saved state, restore it.  If we can reset the device,
>  	 * even better.  Resetting with current state seems better than
> diff --git a/drivers/vfio/pci/vfio_pci_zdev.c b/drivers/vfio/pci/vfio_pci_zdev.c
> index ea4c0d2b0663..686f2e75e392 100644
> --- a/drivers/vfio/pci/vfio_pci_zdev.c
> +++ b/drivers/vfio/pci/vfio_pci_zdev.c
> @@ -11,6 +11,7 @@
>  #include <linux/uaccess.h>
>  #include <linux/vfio.h>
>  #include <linux/vfio_zdev.h>
> +#include <linux/kvm_host.h>
>  #include <asm/pci_clp.h>
>  #include <asm/pci_io.h>
>  
> @@ -136,3 +137,26 @@ int vfio_pci_info_zdev_add_caps(struct vfio_pci_core_device *vdev,
>  
>  	return ret;
>  }
> +
> +int vfio_pci_zdev_open_device(struct vfio_pci_core_device *vdev)
> +{
> +	struct zpci_dev *zdev = to_zpci(vdev->pdev);
> +
> +	if (!zdev)
> +		return -ENODEV;
> +
> +	if (!vdev->vdev.kvm)
> +		return 0;
> +
> +	return kvm_s390_pci_register_kvm(zdev, vdev->vdev.kvm);
> +}
> +
> +void vfio_pci_zdev_close_device(struct vfio_pci_core_device *vdev)
> +{
> +	struct zpci_dev *zdev = to_zpci(vdev->pdev);
> +
> +	if (!zdev || !vdev->vdev.kvm)
> +		return;
> +
> +	kvm_s390_pci_unregister_kvm(zdev);
> +}
> diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
> index 63af2897939c..d5d9e17f0156 100644
> --- a/include/linux/vfio_pci_core.h
> +++ b/include/linux/vfio_pci_core.h
> @@ -209,12 +209,22 @@ static inline int vfio_pci_igd_init(struct vfio_pci_core_device *vdev)
>  #ifdef CONFIG_VFIO_PCI_ZDEV_KVM
>  extern int vfio_pci_info_zdev_add_caps(struct vfio_pci_core_device *vdev,
>  				       struct vfio_info_cap *caps);
> +int vfio_pci_zdev_open_device(struct vfio_pci_core_device *vdev);
> +void vfio_pci_zdev_close_device(struct vfio_pci_core_device *vdev);
>  #else
>  static inline int vfio_pci_info_zdev_add_caps(struct vfio_pci_core_device *vdev,
>  					      struct vfio_info_cap *caps)
>  {
>  	return -ENODEV;
>  }
> +
> +static inline int vfio_pci_zdev_open_device(struct vfio_pci_core_device *vdev)
> +{
> +	return 0;
> +}
> +
> +static inline void vfio_pci_zdev_close_device(struct vfio_pci_core_device *vdev)
> +{}
>  #endif
>  
>  /* Will be exported for vfio pci drivers usage */