[PATCH 26/32] vfio-pci/zdev: wire up group notifier

Matthew Rosato
2021-12-07T21:00:51Z

KVM zPCI passthrough device logic will need a reference to the associated
kvm guest that has access to the device. Let's register a group notifier
for VFIO_GROUP_NOTIFY_SET_KVM to catch this information in order to create
an association between a kvm guest and the host zdev.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
---
arch/s390/include/asm/kvm_pci.h | 2 ++
drivers/vfio/pci/vfio_pci_core.c | 2 ++
drivers/vfio/pci/vfio_pci_zdev.c | 54 ++++++++++++++++++++++++++++++++
include/linux/vfio_pci_core.h | 12 +++++++
4 files changed, 70 insertions(+)

diff --git a/arch/s390/include/asm/kvm_pci.h b/arch/s390/include/asm/kvm_pci.h
index 97e3a369135d..6526908ac834 100644
--- a/arch/s390/include/asm/kvm_pci.h
+++ b/arch/s390/include/asm/kvm_pci.h
@@ -17,6 +17,7 @@
#include <linux/kvm.h>
#include <linux/pci.h>
#include <linux/mutex.h>
+#include <linux/notifier.h>
#include <asm/pci_insn.h>
#include <asm/pci_dma.h>

@@ -33,6 +34,7 @@ struct kvm_zdev {
u64 rpcit_count;
struct kvm_zdev_ioat ioat;
struct zpci_fib fib;
+ struct notifier_block nb;
};

extern int kvm_s390_pci_dev_open(struct zpci_dev *zdev);
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index f948e6cd2993..fc57d4d0abbe 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -452,6 +452,7 @@ void vfio_pci_core_close_device(struct vfio_device *core_vdev)

vfio_pci_vf_token_user_add(vdev, -1);
vfio_spapr_pci_eeh_release(vdev->pdev);
+ vfio_pci_zdev_release(vdev);
vfio_pci_core_disable(vdev);

mutex_lock(&vdev->igate);
@@ -470,6 +471,7 @@ EXPORT_SYMBOL_GPL(vfio_pci_core_close_device);
void vfio_pci_core_finish_enable(struct vfio_pci_core_device *vdev)
{
vfio_pci_probe_mmaps(vdev);
+ vfio_pci_zdev_open(vdev);
vfio_spapr_pci_eeh_open(vdev->pdev);
vfio_pci_vf_token_user_add(vdev, 1);
}
diff --git a/drivers/vfio/pci/vfio_pci_zdev.c b/drivers/vfio/pci/vfio_pci_zdev.c
index ea4c0d2b0663..cfd7f44b06c1 100644
--- a/drivers/vfio/pci/vfio_pci_zdev.c
+++ b/drivers/vfio/pci/vfio_pci_zdev.c
@@ -13,6 +13,7 @@
#include <linux/vfio_zdev.h>
#include <asm/pci_clp.h>
#include <asm/pci_io.h>
+#include <asm/kvm_pci.h>

#include <linux/vfio_pci_core.h>

@@ -136,3 +137,56 @@ int vfio_pci_info_zdev_add_caps(struct vfio_pci_core_device *vdev,

return ret;
}
+
+static int vfio_pci_zdev_group_notifier(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct kvm_zdev *kzdev = container_of(nb, struct kvm_zdev, nb);
+
+ if (action == VFIO_GROUP_NOTIFY_SET_KVM) {
+ if (!data || !kzdev->zdev)
+ return NOTIFY_DONE;
+ if (kvm_s390_pci_attach_kvm(kzdev->zdev, data))
+ return NOTIFY_DONE;
+ }
+
+ return NOTIFY_OK;
+}
+
+int vfio_pci_zdev_open(struct vfio_pci_core_device *vdev)
+{
+ unsigned long events = VFIO_GROUP_NOTIFY_SET_KVM;
+ struct zpci_dev *zdev = to_zpci(vdev->pdev);
+ int ret;
+
+ if (!zdev)
+ return -ENODEV;
+
+ ret = kvm_s390_pci_dev_open(zdev);
+ if (ret)
+ return -ENODEV;
+
+ zdev->kzdev->nb.notifier_call = vfio_pci_zdev_group_notifier;
+
+ ret = vfio_register_notifier(vdev->vdev.dev, VFIO_GROUP_NOTIFY,
+ &events, &zdev->kzdev->nb);
+ if (ret)
+ kvm_s390_pci_dev_release(zdev);
+
+ return ret;
+}
+
+int vfio_pci_zdev_release(struct vfio_pci_core_device *vdev)
+{
+ struct zpci_dev *zdev = to_zpci(vdev->pdev);
+
+ if (!zdev || !zdev->kzdev)
+ return -ENODEV;
+
+ vfio_unregister_notifier(vdev->vdev.dev, VFIO_GROUP_NOTIFY,
+ &zdev->kzdev->nb);
+
+ kvm_s390_pci_dev_release(zdev);
+
+ return 0;
+}
diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index 5e2bca3b89db..14079da409f1 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -198,12 +198,24 @@ static inline int vfio_pci_igd_init(struct vfio_pci_core_device *vdev)
#ifdef CONFIG_VFIO_PCI_ZDEV
extern int vfio_pci_info_zdev_add_caps(struct vfio_pci_core_device *vdev,
struct vfio_info_cap *caps);
+int vfio_pci_zdev_open(struct vfio_pci_core_device *vdev);
+int vfio_pci_zdev_release(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(struct vfio_pci_core_device *vdev)
+{
+ return -ENODEV;
+}
+
+static inline int vfio_pci_zdev_release(struct vfio_pci_core_device *vdev)
+{
+ return -ENODEV;
+}
#endif

/* Will be exported for vfio pci drivers usage */
--
2.27.0