Re: [PATCH v6 2/6] drm/i915/gvt: OpRegion support for GVT-g

[Zhenyu Wang <zhenyuw@linux.intel.com>]

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On 2017.05.27 16:38:48 +0800, Xiaoguang Chen wrote:
> OpRegion is needed to support display related operation for
> intel vgpu.
> 
> A vfio device region is added to intel vgpu to deliver the
> host OpRegion information to user space so user space can
> construct the OpRegion for vgpu.
> 
> Signed-off-by: Bing Niu <bing.niu@intel.com>
> Signed-off-by: Xiaoguang Chen <xiaoguang.chen@intel.com>
> ---
>  drivers/gpu/drm/i915/gvt/kvmgt.c    | 97 +++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/gvt/opregion.c |  8 ++-
>  2 files changed, 104 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 3c6a02b..389f072 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -53,6 +53,8 @@ static const struct intel_gvt_ops *intel_gvt_ops;
>  #define VFIO_PCI_INDEX_TO_OFFSET(index) ((u64)(index) << VFIO_PCI_OFFSET_SHIFT)
>  #define VFIO_PCI_OFFSET_MASK    (((u64)(1) << VFIO_PCI_OFFSET_SHIFT) - 1)
>  
> +#define OPREGION_SIGNATURE "IntelGraphicsMem"
> +
>  struct vfio_region;
>  struct intel_vgpu_regops {
>  	size_t (*rw)(struct intel_vgpu *vgpu, char *buf,
> @@ -436,6 +438,92 @@ static void kvmgt_protect_table_del(struct kvmgt_guest_info *info,
>  	}
>  }
>  
> +static size_t intel_vgpu_reg_rw_opregion(struct intel_vgpu *vgpu, char *buf,
> +		size_t count, loff_t *ppos, bool iswrite)
> +{
> +	unsigned int i = VFIO_PCI_OFFSET_TO_INDEX(*ppos) -
> +			VFIO_PCI_NUM_REGIONS;
> +	void *base = vgpu->vdev.region[i].data;
> +	loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK;
> +
> +	if (pos >= vgpu->vdev.region[i].size || iswrite) {
> +		gvt_vgpu_err("invalid op or offset for Intel vgpu OpRegion\n");
> +		return -EINVAL;
> +	}
> +	count = min(count, (size_t)(vgpu->vdev.region[i].size - pos));
> +	memcpy(buf, base + pos, count);
> +
> +	return count;
> +}
> +
> +static void intel_vgpu_reg_release_opregion(struct intel_vgpu *vgpu,
> +		struct vfio_region *region)
> +{
> +	memunmap(region->data);
> +}
> +
> +static const struct intel_vgpu_regops intel_vgpu_regops_opregion = {
> +	.rw = intel_vgpu_reg_rw_opregion,
> +	.release = intel_vgpu_reg_release_opregion,
> +};
> +
> +static int intel_vgpu_register_reg(struct intel_vgpu *vgpu,
> +		unsigned int type, unsigned int subtype,
> +		const struct intel_vgpu_regops *ops,
> +		size_t size, u32 flags, void *data)
> +{
> +	struct vfio_region *region;
> +
> +	region = krealloc(vgpu->vdev.region,
> +			(vgpu->vdev.num_regions + 1) * sizeof(*region),
> +			GFP_KERNEL);
> +	if (!region)
> +		return -ENOMEM;
> +
> +	vgpu->vdev.region = region;
> +	vgpu->vdev.region[vgpu->vdev.num_regions].type = type;
> +	vgpu->vdev.region[vgpu->vdev.num_regions].subtype = subtype;
> +	vgpu->vdev.region[vgpu->vdev.num_regions].ops = ops;
> +	vgpu->vdev.region[vgpu->vdev.num_regions].size = size;
> +	vgpu->vdev.region[vgpu->vdev.num_regions].flags = flags;
> +	vgpu->vdev.region[vgpu->vdev.num_regions].data = data;
> +	vgpu->vdev.num_regions++;
> +
> +	return 0;
> +}
> +
> +static int intel_vgpu_reg_init_opregion(struct intel_vgpu *vgpu)
> +{
> +	unsigned int addr;
> +	void *base;
> +	int ret;
> +
> +	addr = vgpu->gvt->opregion.opregion_pa;
> +	if (!addr || !(~addr))
> +		return -ENODEV;
> +
> +	base = memremap(addr, OPREGION_SIZE, MEMREMAP_WB);
> +	if (!base)
> +		return -ENOMEM;
> +
> +	if (memcmp(base, OPREGION_SIGNATURE, 16)) {
> +		memunmap(base);
> +		return -EINVAL;
> +	}
> +
> +	ret = intel_vgpu_register_reg(vgpu,
> +			PCI_VENDOR_ID_INTEL | VFIO_REGION_TYPE_PCI_VENDOR_TYPE,
> +			VFIO_REGION_SUBTYPE_INTEL_IGD_OPREGION,
> +			&intel_vgpu_regops_opregion, OPREGION_SIZE,
> +			VFIO_REGION_INFO_FLAG_READ, base);
> +	if (ret) {
> +		memunmap(base);
> +		return ret;
> +	}
> +
> +	return ret;
> +}
> +
>  static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
>  {
>  	struct intel_vgpu *vgpu = NULL;
> @@ -467,6 +555,15 @@ static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
>  	vgpu->vdev.mdev = mdev;
>  	mdev_set_drvdata(mdev, vgpu);
>  
> +	ret = intel_vgpu_reg_init_opregion(vgpu);
> +	if (ret) {
> +		gvt_vgpu_err("create OpRegion failed\n");
> +		goto out;
> +	}

Still need to handle error path for created vgpu.

> +
> +	gvt_dbg_core("create OpRegion succeeded for mdev:%s\n",
> +			dev_name(mdev_dev(mdev)));
> +
>  	gvt_dbg_core("intel_vgpu_create succeeded for mdev: %s\n",
>  		     dev_name(mdev_dev(mdev)));
>  	ret = 0;
> diff --git a/drivers/gpu/drm/i915/gvt/opregion.c b/drivers/gpu/drm/i915/gvt/opregion.c
> index 3117991..5c7496d 100644
> --- a/drivers/gpu/drm/i915/gvt/opregion.c
> +++ b/drivers/gpu/drm/i915/gvt/opregion.c
> @@ -114,6 +114,7 @@ void intel_vgpu_clean_opregion(struct intel_vgpu *vgpu)
>  int intel_vgpu_init_opregion(struct intel_vgpu *vgpu, u32 gpa)
>  {
>  	int ret;
> +	unsigned long pfn;
>  
>  	gvt_dbg_core("vgpu%d: init vgpu opregion\n", vgpu->id);
>  
> @@ -127,7 +128,12 @@ int intel_vgpu_init_opregion(struct intel_vgpu *vgpu, u32 gpa)
>  		ret = map_vgpu_opregion(vgpu, true);
>  		if (ret)
>  			return ret;
> -	}
> +	} else {
> +		pfn = intel_gvt_hypervisor_gfn_to_mfn(vgpu, gpa >> PAGE_SHIFT);
> +		vgpu_opregion(vgpu)->va = memremap(pfn << PAGE_SHIFT,
> +						INTEL_GVT_OPREGION_SIZE,
> +						MEMREMAP_WB);
> +		}

better to use switch for explicit KVM case, and no return check?

>  
>  	return 0;
>  }
> -- 
> 2.7.4
> 

-- 
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