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From: Yan Zhao <yan.y.zhao@intel.com>
To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: alex.williamson@redhat.com, cohuck@redhat.com,
	zhenyuw@linux.intel.com, zhi.a.wang@intel.com,
	kevin.tian@intel.com, shaopeng.he@intel.com, yi.l.liu@intel.com,
	xin.zeng@intel.com, hang.yuan@intel.com,
	Yan Zhao <yan.y.zhao@intel.com>
Subject: [RFC PATCH v4 02/10] vfio/pci: macros to generate module_init and module_exit for vendor modules
Date: Sun, 17 May 2020 22:45:10 -0400	[thread overview]
Message-ID: <20200518024510.14115-1-yan.y.zhao@intel.com> (raw)
In-Reply-To: <20200518024202.13996-1-yan.y.zhao@intel.com>

vendor modules call macro module_vfio_pci_register_vendor_handler to
generate module_init and module_exit.
It is necessary to ensure that vendor modules always call
vfio_pci_register_vendor_driver() on driver loading and
vfio_pci_unregister_vendor_driver on driver unloading,
because
(1) at compiling time, there's only a dependency of vendor modules on
vfio_pci.
(2) at runtime,
- vendor modules add refs of vfio_pci on a successful calling of
  vfio_pci_register_vendor_driver() and deref of vfio_pci on a
  successful calling of vfio_pci_unregister_vendor_driver().
- vfio_pci only adds refs of vendor module on a successful probe of vendor
  driver.
  vfio_pci derefs vendor module when unbinding from a device.

So, after vfio_pci is unbound from a device, the vendor module to that
device is free to get unloaded. However, if that vendor module does not
call vfio_pci_unregister_vendor_driver() in its module_exit, vfio_pci may
hold a stale pointer to vendor module.

Cc: Kevin Tian <kevin.tian@intel.com>
Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
---
 include/linux/vfio.h | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 3e53deb012b6..f3746608c2d9 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -223,4 +223,31 @@ struct vfio_pci_vendor_driver_ops {
 };
 int __vfio_pci_register_vendor_driver(struct vfio_pci_vendor_driver_ops *ops);
 void vfio_pci_unregister_vendor_driver(struct vfio_device_ops *device_ops);
+
+#define vfio_pci_register_vendor_driver(__name, __probe, __remove,	\
+					__device_ops)			\
+static struct vfio_pci_vendor_driver_ops  __ops ## _node = {		\
+	.owner		= THIS_MODULE,					\
+	.name		= __name,					\
+	.probe		= __probe,					\
+	.remove		= __remove,					\
+	.device_ops	= __device_ops,					\
+};									\
+__vfio_pci_register_vendor_driver(&__ops ## _node)
+
+#define module_vfio_pci_register_vendor_handler(name, probe, remove,	\
+						device_ops)		\
+static int __init device_ops ## _module_init(void)			\
+{									\
+	vfio_pci_register_vendor_driver(name, probe, remove,		\
+					device_ops);			\
+	return 0;							\
+};									\
+static void __exit device_ops ## _module_exit(void)			\
+{									\
+	vfio_pci_unregister_vendor_driver(device_ops);			\
+};									\
+module_init(device_ops ## _module_init);				\
+module_exit(device_ops ## _module_exit)
+
 #endif /* VFIO_H */
-- 
2.17.1


  parent reply	other threads:[~2020-05-18  2:55 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-18  2:42 [RFC PATCH v4 00/10] Introduce vendor ops in vfio-pci Yan Zhao
2020-05-18  2:43 ` [RFC PATCH v4 01/10] vfio/pci: register/unregister vfio_pci_vendor_driver_ops Yan Zhao
2020-05-18  2:45 ` Yan Zhao [this message]
2020-06-04 15:01   ` [RFC PATCH v4 02/10] vfio/pci: macros to generate module_init and module_exit for vendor modules Cornelia Huck
2020-06-05  2:05     ` Yan Zhao
2020-05-18  2:49 ` [RFC PATCH v4 03/10] vfio/pci: export vendor_data, irq_type, num_regions, pdev and functions in vfio_pci_ops Yan Zhao
2020-05-18  2:49 ` [RFC PATCH v4 04/10] vfio/pci: let vfio_pci know number of vendor regions and vendor irqs Yan Zhao
2020-06-04 15:25   ` Cornelia Huck
2020-06-05  2:15     ` Yan Zhao
2020-06-11 12:31       ` David Edmondson
2020-06-11 23:09         ` Yan Zhao
2020-05-18  2:50 ` [RFC PATCH v4 05/10] vfio/pci: export vfio_pci_get_barmap Yan Zhao
2020-05-18  2:50 ` [RFC PATCH v4 06/10] vfio: Define device specific irq type capability Yan Zhao
2020-05-18  2:52 ` [RFC PATCH v4 07/10] vfio/pci: introduce a new irq type VFIO_IRQ_TYPE_REMAP_BAR_REGION Yan Zhao
2020-05-18  2:56   ` [QEMU RFC PATCH v4] hw/vfio/pci: remap bar region irq Yan Zhao
2020-05-29 21:45   ` [RFC PATCH v4 07/10] vfio/pci: introduce a new irq type VFIO_IRQ_TYPE_REMAP_BAR_REGION Alex Williamson
2020-06-01  6:57     ` Yan Zhao
2020-06-01 16:43       ` Alex Williamson
2020-06-02  8:28         ` Yan Zhao
2020-06-02 19:34           ` Alex Williamson
2020-06-03  1:40             ` Yan Zhao
2020-06-03 23:04               ` Alex Williamson
2020-06-04  2:42                 ` Yan Zhao
2020-06-04  4:10                   ` Alex Williamson
2020-06-05  0:26                     ` He, Shaopeng
2020-06-05 17:54                       ` Alex Williamson
2020-06-05  2:02                     ` Yan Zhao
2020-06-05 16:13                       ` Alex Williamson
2020-06-10  5:23                         ` Yan Zhao
2020-06-19 22:55                           ` Alex Williamson
2020-06-22  3:34                             ` Yan Zhao
2020-05-18  2:53 ` [RFC PATCH v4 08/10] i40e/vf_migration: VF live migration - pass-through VF first Yan Zhao
2020-06-10  8:59   ` Xiang Zheng
2020-06-11  0:23     ` Yan Zhao
2020-06-11  2:27       ` Xiang Zheng
2020-06-11 23:10         ` Yan Zhao
2020-05-18  2:54 ` [RFC PATCH v4 09/10] i40e/vf_migration: register a migration vendor region Yan Zhao
2020-05-18  2:54 ` [RFC PATCH v4 10/10] i40e/vf_migration: vendor defined irq_type to support dynamic bar map Yan Zhao

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