RE: [PATCH v2 2/5] drm/i915/gvt: OpRegion support for GVT-g

[Chen, Xiaoguang]

Hi min,

>-----Original Message-----
>From: He, Min
>Sent: Thursday, May 18, 2017 11:44 PM
>To: Chen, Xiaoguang <xiaoguang.chen@xxxxxxxxx>;
>alex.williamson@xxxxxxxxxx; kraxel@xxxxxxxxxx; intel-
>gfx@xxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
>zhenyuw@xxxxxxxxxxxxxxx; Lv, Zhiyuan <zhiyuan.lv@xxxxxxxxx>; intel-gvt-
>dev@xxxxxxxxxxxxxxxxxxxxx; Wang, Zhi A <zhi.a.wang@xxxxxxxxx>; Tian, Kevin
><kevin.tian@xxxxxxxxx>
>Cc: Niu, Bing <bing.niu@xxxxxxxxx>; Chen, Xiaoguang
><xiaoguang.chen@xxxxxxxxx>
>Subject: RE: [PATCH v2 2/5] drm/i915/gvt: OpRegion support for GVT-g
>
>Xiaoguang,
>I have some comments inline. Thanks.
>
>> -----Original Message-----
>> From: intel-gvt-dev
>> [mailto:intel-gvt-dev-bounces@xxxxxxxxxxxxxxxxxxxxx] On Behalf Of
>> Xiaoguang Chen
>> Sent: Thursday, May 18, 2017 2:50 AM
>> To: alex.williamson@xxxxxxxxxx; kraxel@xxxxxxxxxx; intel-
>> gfx@xxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
>> zhenyuw@xxxxxxxxxxxxxxx; Lv, Zhiyuan <zhiyuan.lv@xxxxxxxxx>;
>> intel-gvt- dev@xxxxxxxxxxxxxxxxxxxxx; Wang, Zhi A
>> <zhi.a.wang@xxxxxxxxx>; Tian, Kevin <kevin.tian@xxxxxxxxx>
>> Cc: Niu, Bing <bing.niu@xxxxxxxxx>; Chen, Xiaoguang
>> <xiaoguang.chen@xxxxxxxxx>
>> Subject: [PATCH v2 2/5] drm/i915/gvt: OpRegion support for GVT-g
>>
>> 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@xxxxxxxxx>
>> Signed-off-by: Xiaoguang Chen <xiaoguang.chen@xxxxxxxxx>
>> ---
>>  drivers/gpu/drm/i915/gvt/kvmgt.c    | 97
>> +++++++++++++++++++++++++++++++++++++
>>  drivers/gpu/drm/i915/gvt/opregion.c | 12 ++++-
>>  2 files changed, 107 insertions(+), 2 deletions(-)
>>
>> 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 @@
>>  #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);
>In current GVT code, we already have a function init_vgpu_opregion, which will
>copy the physical opregion into a per vgpu structure:
>vgpu_opregion(vgpu)->va, why donât you reuse this function and set the
>vgpu_opregion(vgpu)->va to the intel_vgpu_register_reg function?
The reason is we do not the know the gpa of the OpRegion.
For KVMGT the gpa of the OpRegion is allocated by seabios.

>
>> +	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;
>> +	}
>> +
>> +	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..99591bc 100644
>> --- a/drivers/gpu/drm/i915/gvt/opregion.c
>> +++ b/drivers/gpu/drm/i915/gvt/opregion.c
>> @@ -283,14 +283,22 @@ int intel_vgpu_emulate_opregion_request(struct
>> intel_vgpu *vgpu, u32 swsci)
>>  {
>>  	u32 *scic, *parm;
>>  	u32 func, subfunc;
>> +	u32 scic_val, parm_val;
>> +	u32 gpa;
>>
>> -	scic = vgpu_opregion(vgpu)->va + INTEL_GVT_OPREGION_SCIC;
>> -	parm = vgpu_opregion(vgpu)->va + INTEL_GVT_OPREGION_PARM;
>> +	memcpy(&gpa, vgpu_cfg_space(vgpu) + INTEL_GVT_PCI_OPREGION,
>> +			sizeof(gpa));
>> +	intel_gvt_hypervisor_read_gpa(vgpu, gpa +
>> INTEL_GVT_OPREGION_SCIC,
>> +			&scic_val, sizeof(scic_val));
>> +	intel_gvt_hypervisor_read_gpa(vgpu, gpa +
>> INTEL_GVT_OPREGION_PARM,
>> +			&parm_val, sizeof(parm_val));
>As I said, you can call init_vgpu_opregion(), then vgpu_opregion(vgpu)->va will be
>valid and you donât need to change here.
>
>>
>>  	if (!(swsci & SWSCI_SCI_SELECT)) {
>>  		gvt_vgpu_err("requesting SMI service\n");
>>  		return 0;
>>  	}
>> +	scic = &scic_val;
>> +	parm = &parm_val;
>>  	/* ignore non 0->1 trasitions */
>>  	if ((vgpu_cfg_space(vgpu)[INTEL_GVT_PCI_SWSCI]
>>  				& SWSCI_SCI_TRIGGER) ||
>> --
>> 1.9.1
>>
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