linux-kernel - [PATCH v8 17/22] vfio-pci/zdev: add open/close device hooks

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Message-Id: <20220524185907.140285-18-mjrosato@linux.ibm.com>
Date:   Tue, 24 May 2022 14:59:02 -0400
From:   Matthew Rosato <mjrosato@...ux.ibm.com>
To:     linux-s390@...r.kernel.org
Cc:     alex.williamson@...hat.com, cohuck@...hat.com,
        schnelle@...ux.ibm.com, farman@...ux.ibm.com, pmorel@...ux.ibm.com,
        borntraeger@...ux.ibm.com, hca@...ux.ibm.com, gor@...ux.ibm.com,
        gerald.schaefer@...ux.ibm.com, agordeev@...ux.ibm.com,
        svens@...ux.ibm.com, frankja@...ux.ibm.com, david@...hat.com,
        imbrenda@...ux.ibm.com, vneethv@...ux.ibm.com,
        oberpar@...ux.ibm.com, freude@...ux.ibm.com, thuth@...hat.com,
        pasic@...ux.ibm.com, pbonzini@...hat.com, corbet@....net,
        jgg@...dia.com, kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-doc@...r.kernel.org
Subject: [PATCH v8 17/22] vfio-pci/zdev: add open/close device hooks

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@...ux.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
--- a/arch/s390/include/asm/pci.h
+++ 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 */
 };
 
 static inline bool zdev_enabled(struct zpci_dev *zdev)
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index a0d69ddaf90d..650494410682 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(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_release(vdev);
 out_free_state:
 	kfree(vdev->pci_saved_state);
 	vdev->pci_saved_state = NULL;
@@ -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
--- 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 +137,29 @@ 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);
+
+	if (!zdev)
+		return -ENODEV;
+
+	if (!vdev->vdev.kvm)
+		return 0;
+
+	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..50ffab782435 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -209,12 +209,24 @@ 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(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 0;
+}
+
+static inline int vfio_pci_zdev_release(struct vfio_pci_core_device *vdev)
+{
+	return 0;
+}
 #endif
 
 /* Will be exported for vfio pci drivers usage */
-- 
2.27.0