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SubjectRe: [PATCH v8 17/22] vfio-pci/zdev: add open/close device hooks
On Tue, May 24, 2022 at 02:59:02PM -0400, Matthew Rosato 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>
> arch/s390/include/asm/pci.h | 2 ++
> drivers/vfio/pci/vfio_pci_core.c | 11 ++++++++++-
> drivers/vfio/pci/vfio_pci_zdev.c | 27 +++++++++++++++++++++++++++
> include/linux/vfio_pci_core.h | 12 ++++++++++++
> 4 files changed, 51 insertions(+), 1 deletion(-)
>
> diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
> index 85eb0ef9d4c3..67fbce1ea0c9 100644
> +++ b/arch/s390/include/asm/pci.h
> @@ -5,6 +5,7 @@
> #include <linux/pci.h>
> #include <linux/mutex.h>
> #include <linux/iommu.h>
> +#include <linux/notifier.h>
> #include <linux/pci_hotplug.h>
> #include <asm-generic/pci.h>
> #include <asm/pci_clp.h>
> @@ -195,6 +196,7 @@ struct zpci_dev {
> struct s390_domain *s390_domain; /* s390 IOMMU domain data */
> struct kvm_zdev *kzdev;
> struct mutex kzdev_lock;
> + struct notifier_block nb; /* vfio notifications */

This is obsolete now right? Same for the #include ?

> @@ -418,6 +424,9 @@ void vfio_pci_core_disable(struct vfio_pci_core_device *vdev)
>
> vdev->needs_reset = true;
>
> + if (vfio_pci_zdev_release(vdev))
> + pci_info(pdev, "%s: Couldn't restore zPCI state\n", __func__);
> +
> /*
> * 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..d0df85c8b204 100644
> +++ 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 +137,29 @@ int vfio_pci_info_zdev_add_caps(struct vfio_pci_core_device *vdev,
>
> return ret;
> }
> +
> +int vfio_pci_zdev_open(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);
> +}
> +
> +int vfio_pci_zdev_release(struct vfio_pci_core_device *vdev)
> +{
> + struct zpci_dev *zdev = to_zpci(vdev->pdev);

Keeping these functions named open_device/close_device wouuld probably
be clearer

> + if (!zdev)
> + return -ENODEV;
> +
> + if (!vdev->vdev.kvm)
> + return 0;
> +
> + return kvm_s390_pci_unregister_kvm(zdev);
> +}

Again this cannot fail, you should make it return void, not ignore the
failure - or at least push the ignoring the failure down to the place
that is causing this.

Otherwise it looks fine to me, thanks

Jason

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