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, 22 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
index 29a32b11953b..7769e469118f 100644
--- a/drivers/gpu/drm/i915/Kconfig
+++ b/drivers/gpu/drm/i915/Kconfig
@@ -57,6 +57,28 @@ config DRM_I915_USERPTR
 
 	  If in doubt, say "Y".
 
+config DRM_I915_GVT
+        bool "Enable Intel GVT-g graphics virtualization host support"
+        depends on DRM_I915
+        default n
+        help
+	  Choose this option if you want to enable Intel GVT-g graphics
+	  virtualization technology host support with integrated graphics.
+	  With GVT-g, it's possible to have one integrated graphics
+	  device shared by multiple VMs under different hypervisors.
+
+	  Note that at least one hypervisor like Xen or KVM is required for
+	  this driver to work, and it only supports newer device from
+	  Broadwell+. For further information and setup guide, you can
+	  visit: http://01.org/igvt-g.
+
+	  Now it's just a stub to support the modifications of i915 for
+	  GVT device model. It requires at least one MPT modules for Xen/KVM
+	  and other components of GVT device model to work. Use it under
+	  you own risk.
+
+	  If in doubt, say "N".
+
 menu "drm/i915 Debugging"
 depends on DRM_I915
 depends on EXPERT