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

From: Zhenyu Wang
Date: Wed May 31 2017 - 00:52:56 EST


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@xxxxxxxxx>
> Signed-off-by: Xiaoguang Chen <xiaoguang.chen@xxxxxxxxx>
> ---
> 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
>

--
Open Source Technology Center, Intel ltd.

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