Re: [PATCH 03/15] drm/i915: gvt: Introduce the basic architecture of GVT-g

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

Hi,

Just a few comments from a non-assigned reviewer.

On 15/05/16 18:32, Zhi Wang wrote:
> This patch introduces the very basic framework of GVT-g device model,
> includes basic prototypes, definitions, 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.
>
> Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
> ---
>   drivers/gpu/drm/i915/Kconfig         |  15 +++
>   drivers/gpu/drm/i915/Makefile        |   5 +
>   drivers/gpu/drm/i915/gvt/Makefile    |   5 +
>   drivers/gpu/drm/i915/gvt/debug.h     |  36 ++++++
>   drivers/gpu/drm/i915/gvt/gvt.c       | 209 +++++++++++++++++++++++++++++++++++
>   drivers/gpu/drm/i915/gvt/gvt.h       |  85 ++++++++++++++
>   drivers/gpu/drm/i915/gvt/hypercall.h |  38 +++++++
>   drivers/gpu/drm/i915/gvt/mpt.h       |  51 +++++++++
>   drivers/gpu/drm/i915/i915_dma.c      |  17 ++-
>   drivers/gpu/drm/i915/i915_drv.h      |  12 ++
>   drivers/gpu/drm/i915/intel_gvt.c     | 106 ++++++++++++++++++
>   drivers/gpu/drm/i915/intel_gvt.h     |  49 ++++++++
>   include/drm/i915_gvt.h               |  31 ++++++
>   13 files changed, 655 insertions(+), 4 deletions(-)
>   create mode 100644 drivers/gpu/drm/i915/gvt/Makefile
>   create mode 100644 drivers/gpu/drm/i915/gvt/debug.h
>   create mode 100644 drivers/gpu/drm/i915/gvt/gvt.c
>   create mode 100644 drivers/gpu/drm/i915/gvt/gvt.h
>   create mode 100644 drivers/gpu/drm/i915/gvt/hypercall.h
>   create mode 100644 drivers/gpu/drm/i915/gvt/mpt.h
>   create mode 100644 drivers/gpu/drm/i915/intel_gvt.c
>   create mode 100644 drivers/gpu/drm/i915/intel_gvt.h
>   create mode 100644 include/drm/i915_gvt.h
>
> diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
> index 29a32b1..782c97c 100644
> --- a/drivers/gpu/drm/i915/Kconfig
> +++ b/drivers/gpu/drm/i915/Kconfig
> @@ -57,6 +57,21 @@ config DRM_I915_USERPTR
>
>   	  If in doubt, say "Y".
>
> +config DRM_I915_GVT
> +        bool "Intel GVT-g host driver"
> +        depends on DRM_I915
> +        default n
> +        help
> +          Enabling GVT-g mediated graphics passthrough technique for Intel i915

pass-through

> +          based integrated graphics card. With GVT-g, it's possible to have one
> +          integrated i915 device shared by multiple VMs. Performance critical
> +          opterations such as apperture accesses and ring buffer operations

operations, aperture

> +          are pass-throughed to VM, with a minimal set of conflicting resources

passed-through to the host or hypervisor ?

> +          (e.g. display settings) mediated by vGT driver. The benefit of vGT
> +          is on both the performance, given that each VM could directly operate
> +          its aperture space and submit commands like running on native, and
> +          the feature completeness, given that a true GEN hardware is exposed.
> +
>   menu "drm/i915 Debugging"
>   depends on DRM_I915
>   depends on EXPERT
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 63c4d2b..e48145b 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -103,6 +103,11 @@ i915-y += i915_vgpu.o
>   # legacy horrors
>   i915-y += i915_dma.o
>
> +ifeq ($(CONFIG_DRM_I915_GVT),y)
> +i915-y += intel_gvt.o
> +include $(src)/gvt/Makefile
> +endif
> +
>   obj-$(CONFIG_DRM_I915)  += i915.o
>
>   CFLAGS_i915_trace_points.o := -I$(src)
> diff --git a/drivers/gpu/drm/i915/gvt/Makefile b/drivers/gpu/drm/i915/gvt/Makefile
> new file mode 100644
> index 0000000..d0f21a6
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/gvt/Makefile
> @@ -0,0 +1,5 @@
> +GVT_DIR := gvt
> +GVT_SOURCE := gvt.o
> +
> +ccflags-y                      += -I$(src) -I$(src)/$(GVT_DIR) -Wall
> +i915-y			       += $(addprefix $(GVT_DIR)/, $(GVT_SOURCE))
> diff --git a/drivers/gpu/drm/i915/gvt/debug.h b/drivers/gpu/drm/i915/gvt/debug.h
> new file mode 100644
> index 0000000..5b067d2
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/gvt/debug.h
> @@ -0,0 +1,36 @@
> +/*
> + * 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.
> + */
> +
> +#ifndef __GVT_DEBUG_H__
> +#define __GVT_DEBUG_H__
> +
> +#define gvt_info(fmt, args...) \
> +	DRM_INFO("gvt: "fmt, ##args)
> +
> +#define gvt_err(fmt, args...) \
> +	DRM_ERROR("gvt: "fmt, ##args)
> +
> +#define gvt_dbg_core(fmt, args...) \
> +	DRM_DEBUG_DRIVER("gvt: core: "fmt, ##args)
> +
> +#endif
> diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
> new file mode 100644
> index 0000000..72ca301
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/gvt/gvt.c
> @@ -0,0 +1,209 @@
> +/*
> + * 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 <linux/kthread.h>
> +
> +#include "gvt.h"
> +
> +struct intel_gvt_host intel_gvt_host;
> +
> +static const char * const supported_hypervisors[] = {
> +	[INTEL_GVT_HYPERVISOR_XEN] = "XEN",
> +	[INTEL_GVT_HYPERVISOR_KVM] = "KVM",
> +};
> +
> +#define MB(x) (x * 1024ULL * 1024ULL)
> +#define GB(x) (x * MB(1024))
> +
> +/*
> + * The layout of BAR0 in BDW:
> + * |< - MMIO 2MB ->|<- Reserved 6MB ->|<- MAX GTT 8MB->|
> + *
> + * GTT offset in BAR0 starts from 8MB to 16MB, and
> + * Whatever GTT size is configured in BIOS,
> + * the size of BAR0 is always 16MB. The actual configured
> + * GTT size can be found in GMCH_CTRL.
> + */
> +static struct intel_gvt_device_info broadwell_device_info = {
> +	.max_gtt_gm_sz = GB(4), /* 4GB */
> +	.gtt_start_offset = MB(8), /* 8MB */
> +	.max_gtt_size = MB(8), /* 8MB */
> +	.gtt_entry_size = 8,
> +	.gtt_entry_size_shift = 3,
> +	.gmadr_bytes_in_cmd = 8,
> +	.mmio_size = MB(2), /* 2MB */
> +	.mmio_bar = 0, /* BAR 0 */
> +	.max_support_vgpu = 8,
> +	.max_surface_size = MB(36),
> +};
> +
> +static int init_gvt_host(void)
> +{
> +	if (WARN(intel_gvt_host.initialized,
> +				"Intel GVT host has been initialized\n"))

Maybe add "already" for extra clarity?

> +		return -EINVAL;
> +
> +	/* Xen DOM U */
> +	if (xen_domain() && !xen_initial_domain())
> +		return -ENODEV;
> +
> +	if (xen_initial_domain()) {
> +		/* 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;
> +	}
> +
> +	if (!intel_gvt_host.mpt) {
> +		gvt_err("Fail to load any MPT modules.\n");
> +		return -EINVAL;
> +	}
> +
> +	if (!intel_gvt_hypervisor_detect_host())
> +		return -ENODEV;
> +
> +	gvt_info("Running with hypervisor %s in host mode\n",
> +			supported_hypervisors[intel_gvt_host.hypervisor_type]);
> +
> +	idr_init(&intel_gvt_host.gvt_idr);
> +	mutex_init(&intel_gvt_host.gvt_idr_lock);
> +
> +	intel_gvt_host.initialized = true;
> +	return 0;
> +}
> +
> +static int init_device_info(struct intel_gvt *gvt)
> +{
> +	if (IS_BROADWELL(gvt->dev_priv))
> +		gvt->device_info = &broadwell_device_info;
> +	else
> +		return -ENODEV;
> +
> +	return 0;
> +}
> +
> +static void free_gvt_device(struct intel_gvt *gvt)
> +{
> +	mutex_lock(&intel_gvt_host.gvt_idr_lock);
> +	idr_remove(&intel_gvt_host.gvt_idr, gvt->id);
> +	mutex_unlock(&intel_gvt_host.gvt_idr_lock);
> +
> +	vfree(gvt);
> +}
> +
> +static struct intel_gvt *alloc_gvt_device(struct drm_i915_private *dev_priv)
> +{
> +	struct intel_gvt *gvt = NULL;

Don't need to initialize since it is assigned to unconditionally below.

> +	int ret;
> +
> +	gvt = vzalloc(sizeof(*gvt));

struct intel_gvt does not seem that large - why not cheaper kzalloc ?

> +	if (!gvt)
> +		return ERR_PTR(-ENOMEM);
> +
> +	mutex_lock(&intel_gvt_host.gvt_idr_lock);
> +	ret = idr_alloc(&intel_gvt_host.gvt_idr, gvt, 0, 0, GFP_KERNEL);
> +	mutex_unlock(&intel_gvt_host.gvt_idr_lock);
> +
> +	if (ret < 0)
> +		goto err;
> +
> +	gvt->id = ret;
> +	mutex_init(&gvt->lock);
> +	gvt->dev_priv = dev_priv;
> +	idr_init(&gvt->vgpu_idr);
> +
> +	return gvt;
> +err:
> +	free_gvt_device(gvt);
> +	return ERR_PTR(ret);
> +}
> +
> +/**
> + * intel_gvt_destroy_device - destroy a GVT device
> + * @gvt_device: gvt device
> + *
> + * This function is called at the driver unloading stage, to destroy a
> + * GVT device and free the related resources.
> + *
> + * Returns:
> + * None
> + */
> +void intel_gvt_destroy_device(void *gvt_device)
> +{
> +	struct intel_gvt *gvt = (struct intel_gvt *)gvt_device;

Hm, why does this function need to take a void * instead of the correct 
type?

> +
> +	free_gvt_device(gvt);
> +}
> +
> +/**
> + * intel_gvt_create_device - create a GVT device
> + * @dev: drm device
> + *
> + * This function is called at the initialization stage, to create a
> + * GVT device and initialize necessary GVT components for it.
> + *
> + * Returns:
> + * pointer to the intel gvt device structure, error pointer if failed.
> + */
> +void *intel_gvt_create_device(void *dev)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(dev);
> +	struct intel_gvt *gvt = NULL;

No need to initialize.

> +	int ret;
> +
> +	if (!intel_gvt_host.initialized) {
> +		ret = init_gvt_host();
> +		if (ret)
> +			return ERR_PTR(ret);
> +	}
> +
> +	gvt_dbg_core("create new gvt device, i915 dev_priv: %p\n", dev_priv);

Probably not that interesting to log dev_priv address ? Can't remember 
every seeing any part of the driver doing it.

> +
> +	gvt = alloc_gvt_device(dev_priv);
> +	if (IS_ERR(gvt)) {
> +		ret = PTR_ERR(gvt);
> +		goto out_err;
> +	}
> +
> +	gvt_dbg_core("init gvt device, id %d\n", gvt->id);
> +
> +	ret = init_device_info(gvt);
> +	if (ret)
> +		goto out_free_gvt_device;

There is some redundacy in supported platform checking between 
init_device_info and is_supported_device. If you don't need both perhaps 
try to simplify the code a bit by eliminating one of them?

> +
> +	gvt_dbg_core("gvt device creation done, id %d\n", gvt->id);
> +
> +	return gvt;
> +
> +out_free_gvt_device:
> +	free_gvt_device(gvt);
> +out_err:
> +	return ERR_PTR(ret);
> +}
> diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
> new file mode 100644
> index 0000000..5ef9e1b
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/gvt/gvt.h
> @@ -0,0 +1,85 @@
> +/*
> + * 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.
> + */
> +
> +#ifndef _GVT_H_
> +#define _GVT_H_
> +
> +#include "i915_drv.h"
> +#include "i915_vgpu.h"
> +
> +#include "debug.h"
> +#include "hypercall.h"
> +
> +#define GVT_MAX_VGPU 8
> +#define GVT_ALIGN(addr, size) ((addr) & (~((typeof(addr))(size) - 1)))

Same as existing kernel's ALIGN ?

> +
> +enum {
> +	INTEL_GVT_HYPERVISOR_XEN = 0,
> +	INTEL_GVT_HYPERVISOR_KVM,
> +};
> +
> +struct intel_gvt_host {
> +	bool initialized;
> +	int hypervisor_type;
> +	struct mutex gvt_idr_lock;
> +	struct idr gvt_idr;
> +	struct intel_gvt_mpt *mpt;
> +};
> +
> +extern struct intel_gvt_host intel_gvt_host;
> +
> +/* Describe the limitation of HW.*/
> +struct intel_gvt_device_info {
> +	u64 max_gtt_gm_sz;
> +	u32 gtt_start_offset;
> +	u32 gtt_end_offset;
> +	u32 max_gtt_size;
> +	u32 gtt_entry_size;
> +	u32 gtt_entry_size_shift;
> +	u32 gmadr_bytes_in_cmd;
> +	u32 mmio_size;
> +	u32 mmio_bar;
> +	u32 max_support_vgpu;
> +	u32 max_surface_size;

What surface is this?

Maybe add some comments for the fields?

> +};
> +
> +struct intel_vgpu {
> +	struct intel_gvt *gvt;
> +	int id;
> +	int vm_id;
> +	bool warn_untrack;
> +};
> +
> +struct intel_gvt {
> +	struct mutex lock;
> +	int id;
> +
> +	struct drm_i915_private *dev_priv;
> +	struct idr vgpu_idr;
> +
> +	struct intel_gvt_device_info *device_info;
> +};
> +
> +#include "mpt.h"
> +
> +#endif
> diff --git a/drivers/gpu/drm/i915/gvt/hypercall.h b/drivers/gpu/drm/i915/gvt/hypercall.h
> new file mode 100644
> index 0000000..254df8b
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/gvt/hypercall.h
> @@ -0,0 +1,38 @@
> +/*
> + * 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.
> + */
> +
> +#ifndef _GVT_HYPERCALL_H_
> +#define _GVT_HYPERCALL_H_
> +
> +/*
> + * 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 {
> +	int (*detect_host)(void);
> +};
> +
> +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/mpt.h b/drivers/gpu/drm/i915/gvt/mpt.h
> new file mode 100644
> index 0000000..d3f23cc
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/gvt/mpt.h
> @@ -0,0 +1,51 @@
> +/*
> + * 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.
> + */
> +
> +#ifndef _GVT_MPT_H_
> +#define _GVT_MPT_H_
> +
> +/**
> + * DOC: Hypervisor Service APIs for GVT-g Core Logic
> + *
> + * This is the glue layer between specific hypervisor MPT modules and GVT-g core
> + * logic. Each kind of hypervisor MPT module provides a collection of function
> + * callbacks via gvt_kernel_dm and will be attached to GVT host when driver
> + * loading. GVT-g core logic will call these APIs to request specific services
> + * from hypervisor.
> + */
> +
> +/**
> + * intel_gvt_hypervisor_detect_host - check if GVT-g is running within
> + * hypervisor host/privilged domain
> + *
> + * Returns:
> + * Zero on success, -ENODEV if current kernel is running inside a VM
> + */
> +static inline int intel_gvt_hypervisor_detect_host(void)
> +{
> +	if (WARN_ON(!intel_gvt_host.mpt))
> +		return -ENODEV;

Is this condition impossible due the check in init_gvt_host ?

> +	return intel_gvt_host.mpt->detect_host();
> +}
> +
> +#endif /* _GVT_MPT_H_ */
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index 547100f..795a5cf 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -35,6 +35,7 @@
>   #include "intel_drv.h"
>   #include <drm/i915_drm.h>
>   #include "i915_drv.h"
> +#include "intel_gvt.h"
>   #include "i915_vgpu.h"
>   #include "i915_trace.h"
>   #include <linux/pci.h>
> @@ -1245,18 +1246,22 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
>   		goto out_ggtt;
>   	}
>
> +	ret = intel_gvt_init(dev);
> +	if (ret)
> +		goto out_ggtt;
> +
>   	/* WARNING: Apparently we must kick fbdev drivers before vgacon,
>   	 * otherwise the vga fbdev driver falls over. */
>   	ret = i915_kick_out_firmware_fb(dev_priv);
>   	if (ret) {
>   		DRM_ERROR("failed to remove conflicting framebuffer drivers\n");
> -		goto out_ggtt;
> +		goto out_gvt;
>   	}
>
>   	ret = i915_kick_out_vgacon(dev_priv);
>   	if (ret) {
>   		DRM_ERROR("failed to remove conflicting VGA console\n");
> -		goto out_ggtt;
> +		goto out_gvt;
>   	}
>
>   	pci_set_master(dev->pdev);
> @@ -1267,7 +1272,7 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
>   		if (ret) {
>   			DRM_ERROR("failed to set DMA mask\n");
>
> -			goto out_ggtt;
> +			goto out_gvt;
>   		}
>   	}
>
> @@ -1297,7 +1302,7 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
>   				     aperture_size);
>   	if (!ggtt->mappable) {
>   		ret = -EIO;
> -		goto out_ggtt;
> +		goto out_gvt;
>   	}
>
>   	ggtt->mtrr = arch_phys_wc_add(ggtt->mappable_base,
> @@ -1330,6 +1335,8 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
>
>   	return 0;
>
> +out_gvt:
> +	intel_gvt_cleanup(dev);
>   out_ggtt:
>   	i915_ggtt_cleanup_hw(dev);
>
> @@ -1488,6 +1495,8 @@ int i915_driver_unload(struct drm_device *dev)
>
>   	intel_fbdev_fini(dev);
>
> +	intel_gvt_cleanup(dev);
> +
>   	ret = i915_gem_suspend(dev);
>   	if (ret) {
>   		DRM_ERROR("failed to idle hardware: %d\n", ret);
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 72f0b02..b256ba7 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1703,6 +1703,10 @@ struct i915_workarounds {
>   	u32 hw_whitelist_count[I915_NUM_ENGINES];
>   };
>
> +struct i915_gvt {
> +	void *gvt_device;

Hm, again, why void * ? Will it be possible for this to hold some non 
i915 pointer in the future?

> +};
> +
>   struct i915_virtual_gpu {
>   	bool active;
>   };
> @@ -1742,6 +1746,8 @@ struct drm_i915_private {
>
>   	struct i915_virtual_gpu vgpu;
>
> +	struct i915_gvt gvt;
> +
>   	struct intel_guc guc;
>
>   	struct intel_csr csr;
> @@ -2868,6 +2874,12 @@ void intel_uncore_forcewake_put__locked(struct drm_i915_private *dev_priv,
>   u64 intel_uncore_edram_size(struct drm_i915_private *dev_priv);
>
>   void assert_forcewakes_inactive(struct drm_i915_private *dev_priv);
> +
> +static inline bool intel_gvt_active(struct drm_i915_private *dev_priv)
> +{
> +	return dev_priv->gvt.gvt_device ? true : false;
> +}
> +
>   static inline bool intel_vgpu_active(struct drm_i915_private *dev_priv)
>   {
>   	return dev_priv->vgpu.active;
> diff --git a/drivers/gpu/drm/i915/intel_gvt.c b/drivers/gpu/drm/i915/intel_gvt.c
> new file mode 100644
> index 0000000..57b4910
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/intel_gvt.c
> @@ -0,0 +1,106 @@
> +/*
> + * 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 "i915_drv.h"
> +#include "intel_gvt.h"
> +
> +/**
> + * DOC: Intel GVT-g host support
> + *
> + * Intel GVT-g is a graphics virtualization technology which shares the
> + * GPU among multiple virtual machines on a time-sharing basis. Each
> + * virtual machine is presented a virtual GPU (vGPU), which has equivalent
> + * features as the underlying physical GPU (pGPU), so i915 driver can run
> + * seamlessly in a virtual machine. This file provides the englightments
> + * of GVT and the necessary components used by GVT in i915 driver.
> + */
> +
> +struct gvt_kernel_params gvt_kparams = {
> +	.enable = false,
> +};
> +
> +/* i915.gvt_enable */
> +module_param_named(gvt_enable, gvt_kparams.enable, bool, 0600);
> +MODULE_PARM_DESC(gvt_enable, "Enable Intel GVT-g host support");
> +
> +static bool is_supported_device(struct drm_device *dev)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(dev);
> +
> +	if (IS_BROADWELL(dev_priv))
> +		return true;
> +
> +	return false;
> +}
> +
> +/**
> + * intel_gvt_init - initialize GVT components
> + * @dev: drm device *
> + *
> + * This function is called at the initialization stage to initialize the
> + * GVT components.
> + */
> +int intel_gvt_init(struct drm_device *dev)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(dev);
> +	void *device;
> +
> +	if (!gvt_kparams.enable) {
> +		DRM_DEBUG_DRIVER("GVT-g is disabled by kernel params\n");
> +		return 0;
> +	}
> +
> +	if (!is_supported_device(dev)) {
> +		DRM_DEBUG_DRIVER("Unsupported device. GVT-g is disabled\n");
> +		return 0;
> +	}
> +
> +	device = intel_gvt_create_device(dev);
> +	if (IS_ERR(device)) {
> +		DRM_DEBUG_DRIVER("GVT-g is disabled\n");
> +		return 0;
> +	}
> +
> +	dev_priv->gvt.gvt_device = device;
> +	DRM_DEBUG_DRIVER("GVT-g is running in host mode\n");

Slightly redundant since init_gvt_host already would have logged a 
gvt_info message to the same effect.

On the topic of which, perhaps code would be clearer if init_gvt_host 
was called explicitly here from intel_gvt_init, and not behind the 
scenes from intel_gvt_create_device ? Or is there a reason it has to be 
like it is which I missed?

> +
> +	return 0;
> +}
> +
> +/**
> + * intel_gvt_cleanup - cleanup GVT components when i915 driver is unloading
> + * @dev: drm device *
> + *
> + * This function is called at the i915 driver unloading stage, to shutdown
> + * GVT components and release the related resources.
> + */
> +void intel_gvt_cleanup(struct drm_device *dev)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(dev);
> +
> +	if (!intel_gvt_active(dev_priv))
> +		return;
> +
> +	intel_gvt_destroy_device(dev_priv->gvt.gvt_device);
> +	dev_priv->gvt.gvt_device = NULL;
> +}
> diff --git a/drivers/gpu/drm/i915/intel_gvt.h b/drivers/gpu/drm/i915/intel_gvt.h
> new file mode 100644
> index 0000000..d9b55ac50
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/intel_gvt.h
> @@ -0,0 +1,49 @@
> +/*
> + * 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.
> + */
> +
> +#ifndef _INTEL_GVT_H_
> +#define _INTEL_GVT_H_
> +
> +#ifdef CONFIG_DRM_I915_GVT
> +
> +#include <drm/i915_gvt.h>
> +
> +struct gvt_kernel_params {
> +	bool enable;
> +};
> +
> +extern struct gvt_kernel_params gvt_kparams;
> +
> +extern int intel_gvt_init(struct drm_device *dev);
> +extern void intel_gvt_cleanup(struct drm_device *dev);
> +#else
> +static inline int intel_gvt_init(struct drm_device *dev)
> +{
> +	return 0;
> +}
> +static inline void intel_gvt_cleanup(struct drm_device *dev)
> +{
> +}
> +#endif
> +
> +#endif /* _INTEL_GVT_H_ */
> diff --git a/include/drm/i915_gvt.h b/include/drm/i915_gvt.h
> new file mode 100644
> index 0000000..e126536
> --- /dev/null
> +++ b/include/drm/i915_gvt.h
> @@ -0,0 +1,31 @@
> +/*
> + * Copyright(c) 2011-2016 Intel Corporation. All rights reserved.
> + * 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, sub license, 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.
> + */
> +#ifndef _I915_GVT_H
> +#define _I915_GVT_H
> +
> +extern void *intel_gvt_create_device(void *dev);
> +extern void intel_gvt_destroy_device(void *gvt_device);
> +
> +#endif /* _I915_GVT_H */
>

Regards,

Tvrtko
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