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.

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>
Acked-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 19b5fe5016bf6617394da4d0e795d62e8d49a857..63893fe00711c32a59793360b0ea3dc343c267d1 100644 (file)
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -198,3 +198,4 @@ 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 b016dc753db96774a57770b7af4d93cf66ecf997..271fb46d4dd0df3fbce52eb93097562027e86aed 100644 (file)
--- 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 a5b760b7bc10ec31651f8158a561ac28dd035c5f..4e8947f33bd00db2a4c4e89fc59be35dc6ce1c5b 100644 (file)
--- 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 @@ out_clean_idr:
        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 b4ab1dad01434f9ebdd6375104433a28c1707f2a..8a4cf995d755bbe04bb323b2d0ead9d9304d0a19 100644 (file)
--- 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 e49a9247ed78bda7481a9eca0f09dbc22482ad63..50798868ab15ae2a0c4e4ca7bd16d727d3b8c9b3 100644 (file)
--- 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 1bbd04d30c4236fa463fa3f892508620d0a00aba..a19e684e621ac7ba884d6f0c2d3eaa312b0d28ca 100644 (file)
--- 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 c95ef77da62cd7d47123c56821fe2e7faf03e184..9b4225d44243b9010836482133124721f4279c68 100644 (file)
--- 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 c22b3e18a0f5ff54530b0676aad6303d6c298889..d74e59e22c9d10f7b9a7465165d52489322315d3 100644 (file)
--- 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");