[v2] drm/i915/gvt: Change KVMGT as self load module

Submitted by Zhenyu Wang on Nov. 30, 2018, 6:51 a.m.

Details

Message ID 20181130065124.4325-1-zhenyuw@linux.intel.com
State New
Headers show
Series "Series without cover letter" ( rev: 2 ) in Intel GVT devel

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Commit Message

Zhenyu Wang Nov. 30, 2018, 6:51 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 reference counting
for any VFIO/mdev creation.

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

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

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     |  17 +++--
 drivers/gpu/drm/i915/gvt/mpt.h       |   3 +
 drivers/gpu/drm/i915/intel_gvt.c     |   9 ---
 8 files changed, 66 insertions(+), 85 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..6b7909d796c9 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
@@ -1459,8 +1460,10 @@  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;
 
@@ -1658,13 +1661,14 @@  static bool kvmgt_guest_exit(struct kvmgt_guest_info *info)
 
 static int kvmgt_attach_vgpu(void *vgpu, unsigned long *handle)
 {
-	/* nothing to do here */
+	if (!try_module_get(THIS_MODULE))
+		return -EINVAL;
 	return 0;
 }
 
 static void kvmgt_detach_vgpu(unsigned long handle)
 {
-	/* nothing to do here */
+	module_put(THIS_MODULE);
 }
 
 static int kvmgt_inject_msi(unsigned long handle, u32 addr, u16 data)
@@ -1849,7 +1853,8 @@  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 +1873,17 @@  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..181194000fbd 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);
 }
 
+extern int intel_gvt_register_hypervisor(struct intel_gvt_mpt *);
+extern 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

On Fri, 30 Nov 2018 14:51:24 +0800
Zhenyu Wang <zhenyuw@linux.intel.com> 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 reference counting
> for any VFIO/mdev creation.

This doesn't sound right and I don't see that it's how it works today.
mdev core doesn't take a reference to the vendor driver, it's the
vendor driver's responsibility to take a module reference when a device
is opened.  Likewise created, but unused devices probably shouldn't
hold a reference, they should be cleaned up on module release
callback.  Thanks,

Alex

On 2018.11.30 08:44:23 -0700, Alex Williamson wrote:
> On Fri, 30 Nov 2018 14:51:24 +0800
> Zhenyu Wang <zhenyuw@linux.intel.com> 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 reference counting
> > for any VFIO/mdev creation.
> 
> This doesn't sound right and I don't see that it's how it works today.
> mdev core doesn't take a reference to the vendor driver, it's the
> vendor driver's responsibility to take a module reference when a device
> is opened.  Likewise created, but unused devices probably shouldn't
> hold a reference, they should be cleaned up on module release
> callback.  Thanks,
> 

In this patch kvmgt driver trys to take module reference when device
created and put when destroy, and yeah I think your point is right,
we'd better handle reference when device is opened or released, and
when hypervisor module releases it would call mdev core device unregister
which has already handled unused devices clean up. Will refresh in that manner.

Thanks