[v6,3/3] drm/i915/gvt: Change KVMGT as self load module

Submitted by Zhenyu Wang on Dec. 7, 2018, 8:16 a.m.

Details

Message ID 20181207081653.1216-4-zhenyuw@linux.intel.com
State Accepted
Series "Change KVMGT into self loadable module"
Commit 9bdb073464d6008ed1839d358e320108ed12daae
Headers show

Commit Message

Zhenyu Wang Dec. 7, 2018, 8:16 a.m.
This trys to make 'kvmgt' module as self loadable instead of loading
by i915/gvt device model. So hypervisor specific module could be
stand-alone, e.g only after loading hypervisor specific module, GVT
feature could be enabled via specific hypervisor interface, e.g VFIO/mdev.

So this trys to use hypervisor module register/unregister interface
for that. Hypervisor module needs to take care of module reference
itself when working for hypervisor interface, e.g for VFIO/mdev,
hypervisor module would reference counting mdev when open and release.

This makes 'kvmgt' module really split from GVT device model. User
needs to load 'kvmgt' to enable VFIO/mdev interface.

v6:
- remove unused variable

v5:
- put module reference in register error path

v4:
- fix checkpatch warning

v3:
- Fix module reference handling for device open and release. Unused
  mdev devices would be cleaned up in device unregister when module unload.

v2:
- Fix kvmgt order after i915 for built-in case

Cc: "Yuan, Hang" <hang.yuan@intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: "He, Min" <min.he@intel.com>
Reviewed-by: Yuan, Hang <hang.yuan@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
---
 drivers/gpu/drm/i915/Makefile        |   1 +
 drivers/gpu/drm/i915/gvt/Makefile    |   1 -
 drivers/gpu/drm/i915/gvt/gvt.c       | 108 +++++++++++----------------
 drivers/gpu/drm/i915/gvt/gvt.h       |   6 +-
 drivers/gpu/drm/i915/gvt/hypercall.h |   7 +-
 drivers/gpu/drm/i915/gvt/kvmgt.c     |  16 +++-
 drivers/gpu/drm/i915/gvt/mpt.h       |   3 +
 drivers/gpu/drm/i915/intel_gvt.c     |   9 ---
 8 files changed, 69 insertions(+), 82 deletions(-)

Patch hide | download patch | download mbox

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 0ff878c994e2..ae0d975a6f34 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -195,3 +195,4 @@  endif
 i915-y += intel_lpe_audio.o
 
 obj-$(CONFIG_DRM_I915) += i915.o
+obj-$(CONFIG_DRM_I915_GVT_KVMGT) += gvt/kvmgt.o
diff --git a/drivers/gpu/drm/i915/gvt/Makefile b/drivers/gpu/drm/i915/gvt/Makefile
index b016dc753db9..271fb46d4dd0 100644
--- a/drivers/gpu/drm/i915/gvt/Makefile
+++ b/drivers/gpu/drm/i915/gvt/Makefile
@@ -7,4 +7,3 @@  GVT_SOURCE := gvt.o aperture_gm.o handlers.o vgpu.o trace_points.o firmware.o \
 
 ccflags-y				+= -I$(src) -I$(src)/$(GVT_DIR)
 i915-y					+= $(addprefix $(GVT_DIR)/, $(GVT_SOURCE))
-obj-$(CONFIG_DRM_I915_GVT_KVMGT)	+= $(GVT_DIR)/kvmgt.o
diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
index a5b760b7bc10..4e8947f33bd0 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.c
+++ b/drivers/gpu/drm/i915/gvt/gvt.c
@@ -187,52 +187,6 @@  static const struct intel_gvt_ops intel_gvt_ops = {
 	.write_protect_handler = intel_vgpu_page_track_handler,
 };
 
-/**
- * intel_gvt_init_host - Load MPT modules and detect if we're running in host
- *
- * This function is called at the driver loading stage. If failed to find a
- * loadable MPT module or detect currently we're running in a VM, then GVT-g
- * will be disabled
- *
- * Returns:
- * Zero on success, negative error code if failed.
- *
- */
-int intel_gvt_init_host(void)
-{
-	if (intel_gvt_host.initialized)
-		return 0;
-
-	/* Xen DOM U */
-	if (xen_domain() && !xen_initial_domain())
-		return -ENODEV;
-
-	/* Try to load MPT modules for hypervisors */
-	if (xen_initial_domain()) {
-		/* In Xen dom0 */
-		intel_gvt_host.mpt = try_then_request_module(
-				symbol_get(xengt_mpt), "xengt");
-		intel_gvt_host.hypervisor_type = INTEL_GVT_HYPERVISOR_XEN;
-	} else {
-#if IS_ENABLED(CONFIG_DRM_I915_GVT_KVMGT)
-		/* not in Xen. Try KVMGT */
-		intel_gvt_host.mpt = try_then_request_module(
-				symbol_get(kvmgt_mpt), "kvmgt");
-		intel_gvt_host.hypervisor_type = INTEL_GVT_HYPERVISOR_KVM;
-#endif
-	}
-
-	/* Fail to load MPT modules - bail out */
-	if (!intel_gvt_host.mpt)
-		return -EINVAL;
-
-	gvt_dbg_core("Running with hypervisor %s in host mode\n",
-			supported_hypervisors[intel_gvt_host.hypervisor_type]);
-
-	intel_gvt_host.initialized = true;
-	return 0;
-}
-
 static void init_device_info(struct intel_gvt *gvt)
 {
 	struct intel_gvt_device_info *info = &gvt->device_info;
@@ -316,7 +270,6 @@  void intel_gvt_clean_device(struct drm_i915_private *dev_priv)
 		return;
 
 	intel_gvt_destroy_idle_vgpu(gvt->idle_vgpu);
-	intel_gvt_hypervisor_host_exit(&dev_priv->drm.pdev->dev);
 	intel_gvt_cleanup_vgpu_type_groups(gvt);
 	intel_gvt_clean_vgpu_types(gvt);
 
@@ -352,13 +305,6 @@  int intel_gvt_init_device(struct drm_i915_private *dev_priv)
 	struct intel_vgpu *vgpu;
 	int ret;
 
-	/*
-	 * Cannot initialize GVT device without intel_gvt_host gets
-	 * initialized first.
-	 */
-	if (WARN_ON(!intel_gvt_host.initialized))
-		return -EINVAL;
-
 	if (WARN_ON(dev_priv->gvt))
 		return -EEXIST;
 
@@ -420,13 +366,6 @@  int intel_gvt_init_device(struct drm_i915_private *dev_priv)
 		goto out_clean_types;
 	}
 
-	ret = intel_gvt_hypervisor_host_init(&dev_priv->drm.pdev->dev, gvt,
-				&intel_gvt_ops);
-	if (ret) {
-		gvt_err("failed to register gvt-g host device: %d\n", ret);
-		goto out_clean_types;
-	}
-
 	vgpu = intel_gvt_create_idle_vgpu(gvt);
 	if (IS_ERR(vgpu)) {
 		ret = PTR_ERR(vgpu);
@@ -441,6 +380,8 @@  int intel_gvt_init_device(struct drm_i915_private *dev_priv)
 
 	gvt_dbg_core("gvt device initialization is done\n");
 	dev_priv->gvt = gvt;
+	intel_gvt_host.dev = &dev_priv->drm.pdev->dev;
+	intel_gvt_host.initialized = true;
 	return 0;
 
 out_clean_types:
@@ -467,6 +408,45 @@  int intel_gvt_init_device(struct drm_i915_private *dev_priv)
 	return ret;
 }
 
-#if IS_ENABLED(CONFIG_DRM_I915_GVT_KVMGT)
-MODULE_SOFTDEP("pre: kvmgt");
-#endif
+int
+intel_gvt_register_hypervisor(struct intel_gvt_mpt *m)
+{
+	int ret;
+	void *gvt;
+
+	if (!intel_gvt_host.initialized)
+		return -ENODEV;
+
+	if (m->type != INTEL_GVT_HYPERVISOR_KVM &&
+	    m->type != INTEL_GVT_HYPERVISOR_XEN)
+		return -EINVAL;
+
+	/* Get a reference for device model module */
+	if (!try_module_get(THIS_MODULE))
+		return -ENODEV;
+
+	intel_gvt_host.mpt = m;
+	intel_gvt_host.hypervisor_type = m->type;
+	gvt = (void *)kdev_to_i915(intel_gvt_host.dev)->gvt;
+
+	ret = intel_gvt_hypervisor_host_init(intel_gvt_host.dev, gvt,
+					     &intel_gvt_ops);
+	if (ret < 0) {
+		gvt_err("Failed to init %s hypervisor module\n",
+			supported_hypervisors[intel_gvt_host.hypervisor_type]);
+		module_put(THIS_MODULE);
+		return -ENODEV;
+	}
+	gvt_dbg_core("Running with hypervisor %s in host mode\n",
+		     supported_hypervisors[intel_gvt_host.hypervisor_type]);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(intel_gvt_register_hypervisor);
+
+void
+intel_gvt_unregister_hypervisor(void)
+{
+	intel_gvt_hypervisor_host_exit(intel_gvt_host.dev);
+	module_put(THIS_MODULE);
+}
+EXPORT_SYMBOL_GPL(intel_gvt_unregister_hypervisor);
diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
index b4ab1dad0143..8a4cf995d755 100644
--- a/drivers/gpu/drm/i915/gvt/gvt.h
+++ b/drivers/gpu/drm/i915/gvt/gvt.h
@@ -52,12 +52,8 @@ 
 
 #define GVT_MAX_VGPU 8
 
-enum {
-	INTEL_GVT_HYPERVISOR_XEN = 0,
-	INTEL_GVT_HYPERVISOR_KVM,
-};
-
 struct intel_gvt_host {
+	struct device *dev;
 	bool initialized;
 	int hypervisor_type;
 	struct intel_gvt_mpt *mpt;
diff --git a/drivers/gpu/drm/i915/gvt/hypercall.h b/drivers/gpu/drm/i915/gvt/hypercall.h
index e49a9247ed78..50798868ab15 100644
--- a/drivers/gpu/drm/i915/gvt/hypercall.h
+++ b/drivers/gpu/drm/i915/gvt/hypercall.h
@@ -33,11 +33,17 @@ 
 #ifndef _GVT_HYPERCALL_H_
 #define _GVT_HYPERCALL_H_
 
+enum hypervisor_type {
+	INTEL_GVT_HYPERVISOR_XEN = 0,
+	INTEL_GVT_HYPERVISOR_KVM,
+};
+
 /*
  * Specific GVT-g MPT modules function collections. Currently GVT-g supports
  * both Xen and KVM by providing dedicated hypervisor-related MPT modules.
  */
 struct intel_gvt_mpt {
+	enum hypervisor_type type;
 	int (*host_init)(struct device *dev, void *gvt, const void *ops);
 	void (*host_exit)(struct device *dev);
 	int (*attach_vgpu)(void *vgpu, unsigned long *handle);
@@ -67,6 +73,5 @@  struct intel_gvt_mpt {
 };
 
 extern struct intel_gvt_mpt xengt_mpt;
-extern struct intel_gvt_mpt kvmgt_mpt;
 
 #endif /* _GVT_HYPERCALL_H_ */
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 1bbd04d30c42..a19e684e621a 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -627,6 +627,12 @@  static int intel_vgpu_open(struct mdev_device *mdev)
 		goto undo_iommu;
 	}
 
+	/* Take a module reference as mdev core doesn't take
+	 * a reference for vendor driver.
+	 */
+	if (!try_module_get(THIS_MODULE))
+		goto undo_group;
+
 	ret = kvmgt_guest_init(mdev);
 	if (ret)
 		goto undo_group;
@@ -679,6 +685,9 @@  static void __intel_vgpu_release(struct intel_vgpu *vgpu)
 					&vgpu->vdev.group_notifier);
 	WARN(ret, "vfio_unregister_notifier for group failed: %d\n", ret);
 
+	/* dereference module reference taken at open */
+	module_put(THIS_MODULE);
+
 	info = (struct kvmgt_guest_info *)vgpu->handle;
 	kvmgt_guest_exit(info);
 
@@ -1849,7 +1858,8 @@  static bool kvmgt_is_valid_gfn(unsigned long handle, unsigned long gfn)
 	return ret;
 }
 
-struct intel_gvt_mpt kvmgt_mpt = {
+static struct intel_gvt_mpt kvmgt_mpt = {
+	.type = INTEL_GVT_HYPERVISOR_KVM,
 	.host_init = kvmgt_host_init,
 	.host_exit = kvmgt_host_exit,
 	.attach_vgpu = kvmgt_attach_vgpu,
@@ -1868,15 +1878,17 @@  struct intel_gvt_mpt kvmgt_mpt = {
 	.put_vfio_device = kvmgt_put_vfio_device,
 	.is_valid_gfn = kvmgt_is_valid_gfn,
 };
-EXPORT_SYMBOL_GPL(kvmgt_mpt);
 
 static int __init kvmgt_init(void)
 {
+	if (intel_gvt_register_hypervisor(&kvmgt_mpt) < 0)
+		return -ENODEV;
 	return 0;
 }
 
 static void __exit kvmgt_exit(void)
 {
+	intel_gvt_unregister_hypervisor();
 }
 
 module_init(kvmgt_init);
diff --git a/drivers/gpu/drm/i915/gvt/mpt.h b/drivers/gpu/drm/i915/gvt/mpt.h
index c95ef77da62c..9b4225d44243 100644
--- a/drivers/gpu/drm/i915/gvt/mpt.h
+++ b/drivers/gpu/drm/i915/gvt/mpt.h
@@ -360,4 +360,7 @@  static inline bool intel_gvt_hypervisor_is_valid_gfn(
 	return intel_gvt_host.mpt->is_valid_gfn(vgpu->handle, gfn);
 }
 
+int intel_gvt_register_hypervisor(struct intel_gvt_mpt *);
+void intel_gvt_unregister_hypervisor(void);
+
 #endif /* _GVT_MPT_H_ */
diff --git a/drivers/gpu/drm/i915/intel_gvt.c b/drivers/gpu/drm/i915/intel_gvt.c
index c22b3e18a0f5..d74e59e22c9d 100644
--- a/drivers/gpu/drm/i915/intel_gvt.c
+++ b/drivers/gpu/drm/i915/intel_gvt.c
@@ -105,15 +105,6 @@  int intel_gvt_init(struct drm_i915_private *dev_priv)
 		return -EIO;
 	}
 
-	/*
-	 * We're not in host or fail to find a MPT module, disable GVT-g
-	 */
-	ret = intel_gvt_init_host();
-	if (ret) {
-		DRM_DEBUG_DRIVER("Not in host or MPT modules not found\n");
-		goto bail;
-	}
-
 	ret = intel_gvt_init_device(dev_priv);
 	if (ret) {
 		DRM_DEBUG_DRIVER("Fail to init GVT device\n");

Comments

Joonas Lahtinen Dec. 20, 2018, 10:05 a.m.
Quoting Zhenyu Wang (2018-12-07 10:16:53)
> This trys to make 'kvmgt' module as self loadable instead of loading
> by i915/gvt device model. So hypervisor specific module could be
> stand-alone, e.g only after loading hypervisor specific module, GVT
> feature could be enabled via specific hypervisor interface, e.g VFIO/mdev.
> 
> So this trys to use hypervisor module register/unregister interface
> for that. Hypervisor module needs to take care of module reference
> itself when working for hypervisor interface, e.g for VFIO/mdev,
> hypervisor module would reference counting mdev when open and release.
> 
> This makes 'kvmgt' module really split from GVT device model. User
> needs to load 'kvmgt' to enable VFIO/mdev interface.
> 
> v6:
> - remove unused variable
> 
> v5:
> - put module reference in register error path
> 
> v4:
> - fix checkpatch warning
> 
> v3:
> - Fix module reference handling for device open and release. Unused
>   mdev devices would be cleaned up in device unregister when module unload.
> 
> v2:
> - Fix kvmgt order after i915 for built-in case
> 
> Cc: "Yuan, Hang" <hang.yuan@intel.com>
> Cc: Alex Williamson <alex.williamson@redhat.com>
> Cc: "He, Min" <min.he@intel.com>
> Reviewed-by: Yuan, Hang <hang.yuan@intel.com>
> Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

For what i915 is concerned, this is the desireable direction. When
combined with the other series about making GVT build independantly,
and golden MMIO state (instead of capturing at boot).

With those This should both expedite the i915 driver loading on DOM0,
when GVT can be loaded as secondary module. And the golden MMIO state
instead of capturing from host would avoid leaking any changes in host
configuration (say, due to BIOS update) to the guests.

So as an intermediary step to that direction, for i915 portion (not that
much in this case) this is:

Acked-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

I'm expecting somebody with more inisght to review the code under
gvt/.

Regards, Joonas