[PATCH v5] drm/i915/gvt: Change KVMGT as self load module

Yuan, Hang hang.yuan at intel.com
Thu Dec 6 09:31:49 UTC 2018


Looks good to me. Thanks.

Reviewed-by: Yuan, Hang <hang.yuan at intel.com>

> -----Original Message-----
> From: Zhenyu Wang [mailto:zhenyuw at linux.intel.com]
> Sent: Thursday, December 6, 2018 4:03 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: intel-gvt-dev at lists.freedesktop.org; Yuan, Hang <hang.yuan at intel.com>;
> Alex Williamson <alex.williamson at redhat.com>
> Subject: [PATCH v5] 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.
> 
> 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 at intel.com>
> Cc: Alex Williamson <alex.williamson at redhat.com>
> Signed-off-by: Zhenyu Wang <zhenyuw at 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     |  21 +++++-
>  drivers/gpu/drm/i915/gvt/mpt.h       |   3 +
>  drivers/gpu/drm/i915/intel_gvt.c     |   9 ---
>  8 files changed, 73 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..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..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



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