[v4] drm/i915/gvt: Change KVMGT as self load module

Submitted by Zhenyu Wang on Dec. 4, 2018, 2:40 a.m.

Details

Message ID 20181204024028.11311-1-zhenyuw@linux.intel.com
State New
Series "Change KVMGT into self loadable module"
Headers show

Commit Message

Zhenyu Wang Dec. 4, 2018, 2:40 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.

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: Alex Williamson <alex.williamson@redhat.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       | 107 +++++++++++----------------
 drivers/gpu/drm/i915/gvt/gvt.h       |   6 +-
 drivers/gpu/drm/i915/gvt/hypercall.h |   7 +-
 drivers/gpu/drm/i915/gvt/kvmgt.c     |  21 +++++-
 drivers/gpu/drm/i915/gvt/mpt.h       |   3 +
 drivers/gpu/drm/i915/intel_gvt.c     |   9 ---
 8 files changed, 72 insertions(+), 83 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..e1c9c20918af 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 +408,44 @@  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]);
+		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..ef248d577e49 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -50,6 +50,7 @@ 
 #include "gvt.h"
 
 static const struct intel_gvt_ops *intel_gvt_ops;
+static struct intel_gvt *intel_gvt;
 
 /* helper macros copied from vfio-pci */
 #define VFIO_PCI_OFFSET_SHIFT   40
@@ -627,6 +628,12 @@  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 +686,9 @@  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);
 
@@ -1459,8 +1469,10 @@  static int kvmgt_host_init(struct device *dev, void *gvt, const void *ops)
 	struct attribute_group **kvm_vgpu_type_groups;
 
 	intel_gvt_ops = ops;
+	intel_gvt = (struct intel_gvt *)gvt;
+
 	if (!intel_gvt_ops->get_gvt_attrs(&kvm_type_attrs,
-			&kvm_vgpu_type_groups))
+					  &kvm_vgpu_type_groups))
 		return -EFAULT;
 	intel_vgpu_ops.supported_type_groups = kvm_vgpu_type_groups;
 
@@ -1849,7 +1861,8 @@  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 +1881,17 @@  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

Zhenyu Wang Dec. 6, 2018, 4:27 a.m.
Ping for any more comments? Or ack?

Adding Min, for head-up notify, I've moved 'kvmgt' into self load
module instead of loaded by i915/gvt, in order to clean up the
dependence, so need to load 'kvmgt.ko' to enable GVT through
VFIO/mdev. Hypervisor module needs to call new register/unregister
function to initialize hypervisor specific interface for GVT. If
AcrnGT rebase on this, it may need to change initial setup too, so
could you double check?

thanks

On 2018.12.04 10:40:28 +0800, Zhenyu Wang wrote:
> 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.
> 
> 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: Alex Williamson <alex.williamson@redhat.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       | 107 +++++++++++----------------
>  drivers/gpu/drm/i915/gvt/gvt.h       |   6 +-
>  drivers/gpu/drm/i915/gvt/hypercall.h |   7 +-
>  drivers/gpu/drm/i915/gvt/kvmgt.c     |  21 +++++-
>  drivers/gpu/drm/i915/gvt/mpt.h       |   3 +
>  drivers/gpu/drm/i915/intel_gvt.c     |   9 ---
>  8 files changed, 72 insertions(+), 83 deletions(-)
> 
> 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..e1c9c20918af 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 +408,44 @@ 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]);
> +		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..ef248d577e49 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -50,6 +50,7 @@
>  #include "gvt.h"
>  
>  static const struct intel_gvt_ops *intel_gvt_ops;
> +static struct intel_gvt *intel_gvt;
>  
>  /* helper macros copied from vfio-pci */
>  #define VFIO_PCI_OFFSET_SHIFT   40
> @@ -627,6 +628,12 @@ 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 +686,9 @@ 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);
>  
> @@ -1459,8 +1469,10 @@ static int kvmgt_host_init(struct device *dev, void *gvt, const void *ops)
>  	struct attribute_group **kvm_vgpu_type_groups;
>  
>  	intel_gvt_ops = ops;
> +	intel_gvt = (struct intel_gvt *)gvt;
> +
>  	if (!intel_gvt_ops->get_gvt_attrs(&kvm_type_attrs,
> -			&kvm_vgpu_type_groups))
> +					  &kvm_vgpu_type_groups))
>  		return -EFAULT;
>  	intel_vgpu_ops.supported_type_groups = kvm_vgpu_type_groups;
>  
> @@ -1849,7 +1861,8 @@ 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 +1881,17 @@ 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");
> -- 
> 2.19.1
> 
> _______________________________________________
> intel-gvt-dev mailing list
> intel-gvt-dev@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev
Yuan, Hang Dec. 6, 2018, 7:17 a.m.
> -----Original Message-----

> From: intel-gvt-dev [mailto:intel-gvt-dev-bounces@lists.freedesktop.org] On

> Behalf Of Zhenyu Wang

> Sent: Tuesday, December 4, 2018 10:40 AM

> To: intel-gfx@lists.freedesktop.org

> Cc: Alex Williamson <alex.williamson@redhat.com>; intel-gvt-

> dev@lists.freedesktop.org

> Subject: [PATCH v4] drm/i915/gvt: Change KVMGT as self load module

> 

> 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.

> 

> 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: Alex Williamson <alex.williamson@redhat.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       | 107 +++++++++++----------------

>  drivers/gpu/drm/i915/gvt/gvt.h       |   6 +-

>  drivers/gpu/drm/i915/gvt/hypercall.h |   7 +-

>  drivers/gpu/drm/i915/gvt/kvmgt.c     |  21 +++++-

>  drivers/gpu/drm/i915/gvt/mpt.h       |   3 +

>  drivers/gpu/drm/i915/intel_gvt.c     |   9 ---

>  8 files changed, 72 insertions(+), 83 deletions(-)

> 

> 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..e1c9c20918af 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 +408,44 @@ 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]);

> +		return -ENODEV;

[Yuan, Hang] put_module in failing case?

> +	}

> +	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);
He, Min Dec. 7, 2018, 7:47 a.m.
Zhenyu,
Overall I think the impact to AcrnGT is not big, we can modify our code to adapt
to the new interfaces. 
But I have some comments embedded. 

> -----Original Message-----
> From: Zhenyu Wang [mailto:zhenyuw@linux.intel.com]
> Sent: Thursday, December 6, 2018 12:28 PM
> To: Yuan, Hang <hang.yuan@intel.com>; Wang, Zhi A
> <zhi.a.wang@intel.com>; Zhang, Xiong Y <xiong.y.zhang@intel.com>; He,
> Min <min.he@intel.com>
> Cc: intel-gfx@lists.freedesktop.org; Alex Williamson
> <alex.williamson@redhat.com>; intel-gvt-dev@lists.freedesktop.org
> Subject: Re: [PATCH v4] drm/i915/gvt: Change KVMGT as self load module
> 
> 
> Ping for any more comments? Or ack?
> 
> Adding Min, for head-up notify, I've moved 'kvmgt' into self load
> module instead of loaded by i915/gvt, in order to clean up the
> dependence, so need to load 'kvmgt.ko' to enable GVT through
> VFIO/mdev. Hypervisor module needs to call new register/unregister
> function to initialize hypervisor specific interface for GVT. If
> AcrnGT rebase on this, it may need to change initial setup too, so
> could you double check?
> 
> thanks
> 
> On 2018.12.04 10:40:28 +0800, Zhenyu Wang wrote:
> > 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.
> >
> > 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: Alex Williamson <alex.williamson@redhat.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       | 107 +++++++++++----------------
> >  drivers/gpu/drm/i915/gvt/gvt.h       |   6 +-
> >  drivers/gpu/drm/i915/gvt/hypercall.h |   7 +-
> >  drivers/gpu/drm/i915/gvt/kvmgt.c     |  21 +++++-
> >  drivers/gpu/drm/i915/gvt/mpt.h       |   3 +
> >  drivers/gpu/drm/i915/intel_gvt.c     |   9 ---
> >  8 files changed, 72 insertions(+), 83 deletions(-)
> >
> > 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..e1c9c20918af 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 +408,44 @@ 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);
I think we can remove the host_init and host_exit interfaces, since now
it's mpt modules who proactively call the GVT-g to initialize and un-initialize,
Thus we can return the intel_gvt_ops in intel_gvt_register_hypervisor() and
moduels initialize its rest part. 
Current kvmgt_init-> intel_gvt_register_hypervisor->host_init seems a little bit
redundant.
But it's up to you to make the call to remove it in this patch or other furture
optimization patches.

> > +	if (ret < 0) {
> > +		gvt_err("Failed to init %s hypervisor module\n",
> > +
> 	supported_hypervisors[intel_gvt_host.hypervisor_type]);
> > +		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;
We can remove this definition, too. 

> > -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..ef248d577e49 100644
> > --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> > +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> > @@ -50,6 +50,7 @@
> >  #include "gvt.h"
> >
> >  static const struct intel_gvt_ops *intel_gvt_ops;
> > +static struct intel_gvt *intel_gvt;
This variable intel_gvt seems useless.

> >
> >  /* helper macros copied from vfio-pci */
> >  #define VFIO_PCI_OFFSET_SHIFT   40
> > @@ -627,6 +628,12 @@ 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 +686,9 @@ 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);
> >
> > @@ -1459,8 +1469,10 @@ static int kvmgt_host_init(struct device *dev,
> void *gvt, const void *ops)
> >  	struct attribute_group **kvm_vgpu_type_groups;
> >
> >  	intel_gvt_ops = ops;
> > +	intel_gvt = (struct intel_gvt *)gvt;
> > +
> >  	if (!intel_gvt_ops->get_gvt_attrs(&kvm_type_attrs,
> > -			&kvm_vgpu_type_groups))
> > +					  &kvm_vgpu_type_groups))
Unrelated to this patch.

> >  		return -EFAULT;
> >  	intel_vgpu_ops.supported_type_groups = kvm_vgpu_type_groups;
> >
> > @@ -1849,7 +1861,8 @@ 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 +1881,17 @@ 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");
> > --
> > 2.19.1
> >
> > _______________________________________________
> > intel-gvt-dev mailing list
> > intel-gvt-dev@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev
> 
> --
> Open Source Technology Center, Intel ltd.
> 
> $gpg --keyserver wwwkeys.pgp.net --recv-keys 4D781827
Zhenyu Wang Dec. 7, 2018, 7:50 a.m.
On 2018.12.07 07:47:59 +0000, He, Min wrote:
> Zhenyu,
> Overall I think the impact to AcrnGT is not big, we can modify our code to adapt
> to the new interfaces. 
> But I have some comments embedded. 
> 

Good!

> > > @@ -467,6 +408,44 @@ 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);
> I think we can remove the host_init and host_exit interfaces, since now
> it's mpt modules who proactively call the GVT-g to initialize and un-initialize,
> Thus we can return the intel_gvt_ops in intel_gvt_register_hypervisor() and
> moduels initialize its rest part. 
> Current kvmgt_init-> intel_gvt_register_hypervisor->host_init seems a little bit
> redundant.
> But it's up to you to make the call to remove it in this patch or other furture
> optimization patches.
>

I'd like to keep as in current approach, as it can keep hypervisor init
function in one place instead of passing gvt host info to hypervisor module.
And calling submodule's init function is fine process I think.

> > > @@ -67,6 +73,5 @@ struct intel_gvt_mpt {
> > >  };
> > >
> > >  extern struct intel_gvt_mpt xengt_mpt;
> We can remove this definition, too. 
>

yeah, but maybe in another xengt cleanup patch.

> > > diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c
> > b/drivers/gpu/drm/i915/gvt/kvmgt.c
> > > index 1bbd04d30c42..ef248d577e49 100644
> > > --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> > > +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> > > @@ -50,6 +50,7 @@
> > >  #include "gvt.h"
> > >
> > >  static const struct intel_gvt_ops *intel_gvt_ops;
> > > +static struct intel_gvt *intel_gvt;
> This variable intel_gvt seems useless.
>

Thanks for pointing this out, was trying to use for exit path,
but looks I missed to remove it finally.