drm/i915: gvt: Introduce the basic architecture of GVT-g

This patch introduces the very basic framework of GVT-g device model,
includes basic prototypes, definitions, initialization.

v12:
- Call intel_gvt_init() in driver early initialization stage. (Chris)

v8:
- Remove the GVT idr and mutex in intel_gvt_host. (Joonas)

v7:
- Refine the URL link in Kconfig. (Joonas)
- Refine the introduction of GVT-g host support in Kconfig. (Joonas)
- Remove the macro GVT_ALIGN(), use round_down() instead. (Joonas)
- Make "struct intel_gvt" a data member in struct drm_i915_private.(Joonas)
	- Remove {alloc, free}_gvt_device()
	- Rename intel_gvt_{create, destroy}_gvt_device()
	- Expost intel_gvt_init_host()
- Remove the dummy "struct intel_gvt" declaration in intel_gvt.h (Joonas)

v6:
- Refine introduction in Kconfig. (Chris)
- The exposed API functions will take struct intel_gvt * instead of
void *. (Chris/Tvrtko)
- Remove most memebers of strct intel_gvt_device_info. Will add them
in the device model patches.(Chris)
- Remove gvt_info() and gvt_err() in debug.h. (Chris)
- Move GVT kernel parameter into i915_params. (Chris)
- Remove include/drm/i915_gvt.h, as GVT-g will be built within i915.
- Remove the redundant struct i915_gvt *, as the functions in i915
will directly take struct intel_gvt *.
- Add more comments for reviewer.

v5:
Take Tvrtko's comments:
- Fix the misspelled words in Kconfig
- Let functions take drm_i915_private * instead of struct drm_device *
- Remove redundant prints/local varible initialization

v3:
Take Joonas' comments:
- Change file name i915_gvt.* to intel_gvt.*
- Move GVT kernel parameter into intel_gvt.c
- Remove redundant debug macros
- Change error handling style
- Add introductions for some stub functions
- Introduce drm/i915_gvt.h.

Take Kevin's comments:
- Move GVT-g host/guest check into intel_vgt_balloon in i915_gem_gtt.c

v2:
- Introduce i915_gvt.c.
It's necessary to introduce the stubs between i915 driver and GVT-g host,
as GVT-g components is configurable in kernel config. When disabled, the
stubs here do nothing.

Take Joonas' comments:
- Replace boolean return value with int.
- Replace customized info/warn/debug macros with DRM macros.
- Document all non-static functions like i915.
- Remove empty and unused functions.
- Replace magic number with marcos.
- Set GVT-g in kernel config to "n" by default.

Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1466078825-6662-5-git-send-email-zhi.a.wang@intel.com
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 145 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
new file mode 100644
index 000000000000..927f4579f5b6
--- /dev/null
+++ b/drivers/gpu/drm/i915/gvt/gvt.c
@@ -0,0 +1,145 @@
+/*
+ * Copyright(c) 2011-2016 Intel Corporation. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/types.h>
+#include <xen/xen.h>
+
+#include "i915_drv.h"
+
+struct intel_gvt_host intel_gvt_host;
+
+static const char * const supported_hypervisors[] = {
+	[INTEL_GVT_HYPERVISOR_XEN] = "XEN",
+	[INTEL_GVT_HYPERVISOR_KVM] = "KVM",
+};
+
+/**
+ * intel_gvt_init_host - Load MPT modules and detect if we're running in host
+ * @gvt: intel gvt device
+ *
+ * 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 {
+		/* not in Xen. Try KVMGT */
+		intel_gvt_host.mpt = try_then_request_module(
+				symbol_get(kvmgt_mpt), "kvm");
+		intel_gvt_host.hypervisor_type = INTEL_GVT_HYPERVISOR_KVM;
+	}
+
+	/* Fail to load MPT modules - bail out */
+	if (!intel_gvt_host.mpt)
+		return -EINVAL;
+
+	/* Try to detect if we're running in host instead of VM. */
+	if (!intel_gvt_hypervisor_detect_host())
+		return -ENODEV;
+
+	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)
+{
+	if (IS_BROADWELL(gvt->dev_priv))
+		gvt->device_info.max_support_vgpus = 8;
+	/* This function will grow large in GVT device model patches. */
+}
+
+/**
+ * intel_gvt_clean_device - clean a GVT device
+ * @gvt: intel gvt device
+ *
+ * This function is called at the driver unloading stage, to free the
+ * resources owned by a GVT device.
+ *
+ */
+void intel_gvt_clean_device(struct drm_i915_private *dev_priv)
+{
+	struct intel_gvt *gvt = &dev_priv->gvt;
+
+	if (WARN_ON(!gvt->initialized))
+		return;
+
+	/* Other de-initialization of GVT components will be introduced. */
+
+	gvt->initialized = false;
+}
+
+/**
+ * intel_gvt_init_device - initialize a GVT device
+ * @dev_priv: drm i915 private data
+ *
+ * This function is called at the initialization stage, to initialize
+ * necessary GVT components.
+ *
+ * Returns:
+ * Zero on success, negative error code if failed.
+ *
+ */
+int intel_gvt_init_device(struct drm_i915_private *dev_priv)
+{
+	struct intel_gvt *gvt = &dev_priv->gvt;
+	/*
+	 * Cannot initialize GVT device without intel_gvt_host gets
+	 * initialized first.
+	 */
+	if (WARN_ON(!intel_gvt_host.initialized))
+		return -EINVAL;
+
+	if (WARN_ON(gvt->initialized))
+		return -EEXIST;
+
+	gvt_dbg_core("init gvt device\n");
+
+	init_device_info(gvt);
+	/*
+	 * Other initialization of GVT components will be introduce here.
+	 */
+	gvt_dbg_core("gvt device creation is done\n");
+	gvt->initialized = true;
+	return 0;
+}