Quoting Zhenyu Wang (2019-06-20 03:15:35)
> On 2019.06.19 18:00:21 -0700, Daniele Ceraolo Spurio wrote:
> > With multiple uncore to initialize (GT vs Display), it makes little
> > sense to have the vgpu_check inside uncore_init(). We also have
> > a catch-22 scenario where the uncore is required to read the vgpu
> > capabilities while the vgpu capabilities are required to decide if
> > we need to initialize forcewake support. To remove this circular
> > dependency, we can perform the required MMIO access by mmapping just
> > the vgtif shared page in mmio space and use raw accessors.
> >
> > v2: rename check_vgpu to detect_vgpu (Chris)
> >
> > Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>
> > Cc: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx>
> > Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
>
> Looks good to me.
>
> Acked-by: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx>
>
> > ---
> > drivers/gpu/drm/i915/i915_drv.c | 2 ++
> > drivers/gpu/drm/i915/i915_pvinfo.h | 5 +++--
> > drivers/gpu/drm/i915/i915_vgpu.c | 35 ++++++++++++++++++++++-------
> > drivers/gpu/drm/i915/i915_vgpu.h | 2 +-
> > drivers/gpu/drm/i915/intel_uncore.c | 2 --
> > 5 files changed, 33 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> > index 00b6512cdee6..8f84ed26e972 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.c
> > +++ b/drivers/gpu/drm/i915/i915_drv.c
> > @@ -1899,6 +1899,8 @@ int i915_driver_load(struct pci_dev *pdev, const struct pci_device_id *ent)
> >
> > disable_rpm_wakeref_asserts(&dev_priv->runtime_pm);
> >
> > + i915_detect_vgpu(dev_priv);
> > +
> > ret = i915_driver_init_mmio(dev_priv);
> > if (ret < 0)
> > goto out_runtime_pm_put;
> > diff --git a/drivers/gpu/drm/i915/i915_pvinfo.h b/drivers/gpu/drm/i915/i915_pvinfo.h
> > index 969e514916ab..ca4661e98f79 100644
> > --- a/drivers/gpu/drm/i915/i915_pvinfo.h
> > +++ b/drivers/gpu/drm/i915/i915_pvinfo.h
> > @@ -110,8 +110,9 @@ struct vgt_if {
> > u32 rsv7[0x200 - 24]; /* pad to one page */
> > } __packed;
> >
> > -#define vgtif_reg(x) \
> > - _MMIO((VGT_PVINFO_PAGE + offsetof(struct vgt_if, x)))
> > +#define vgtif_offset(x) (offsetof(struct vgt_if, x))
> > +
> > +#define vgtif_reg(x) _MMIO(VGT_PVINFO_PAGE + vgtif_offset(x))
> >
> > /* vGPU display status to be used by the host side */
> > #define VGT_DRV_DISPLAY_NOT_READY 0
> > diff --git a/drivers/gpu/drm/i915/i915_vgpu.c b/drivers/gpu/drm/i915/i915_vgpu.c
> > index 94d3992b599d..1a8f7c731126 100644
> > --- a/drivers/gpu/drm/i915/i915_vgpu.c
> > +++ b/drivers/gpu/drm/i915/i915_vgpu.c
> > @@ -52,34 +52,53 @@
> > */
> >
> > /**
> > - * i915_check_vgpu - detect virtual GPU
> > + * i915_detect_vgpu - detect virtual GPU
> > * @dev_priv: i915 device private
> > *
> > * This function is called at the initialization stage, to detect whether
> > * running on a vGPU.
> > */
> > -void i915_check_vgpu(struct drm_i915_private *dev_priv)
> > +void i915_detect_vgpu(struct drm_i915_private *dev_priv)
> > {
> > - struct intel_uncore *uncore = &dev_priv->uncore;
> > + struct pci_dev *pdev = dev_priv->drm.pdev;
> > u64 magic;
> > u16 version_major;
> > + void __iomem *shared_area;
> >
> > BUILD_BUG_ON(sizeof(struct vgt_if) != VGT_PVINFO_SIZE);
> >
> > - magic = __raw_uncore_read64(uncore, vgtif_reg(magic));
> > - if (magic != VGT_MAGIC)
> > + /*
> > + * This is called before we setup the main MMIO BAR mappings used via
> > + * the uncore structure, so we need to access the BAR directly. Since
> > + * we do not support VGT on older gens, return early so we don't have
> > + * to consider differently numbered or sized MMIO bars
> > + */
> > + if (INTEL_GEN(dev_priv) < 6)
> > + return;
> > +
> > + shared_area = pci_iomap_range(pdev, 0, VGT_PVINFO_PAGE, VGT_PVINFO_SIZE);
> > + if (!shared_area) {
> > + DRM_ERROR("failed to map MMIO bar to check for VGT\n");
> > return;
> > + }
> > +
> > + magic = readq(shared_area + vgtif_offset(magic));
> > + if (magic != VGT_MAGIC)
> > + goto out;
> >
> > - version_major = __raw_uncore_read16(uncore, vgtif_reg(version_major));
> > + version_major = readw(shared_area + vgtif_offset(version_major));
> > if (version_major < VGT_VERSION_MAJOR) {
> > DRM_INFO("VGT interface version mismatch!\n");
> > - return;
> > + goto out;
> > }
> >
> > - dev_priv->vgpu.caps = __raw_uncore_read32(uncore, vgtif_reg(vgt_caps));
> > + dev_priv->vgpu.caps = readl(shared_area + vgtif_offset(vgt_caps));
> >
> > dev_priv->vgpu.active = true;
> > DRM_INFO("Virtual GPU for Intel GVT-g detected.\n");
> > +
> > +out:
> > + pci_iounmap(pdev, shared_area);
> > }
> >
> > bool intel_vgpu_has_full_ppgtt(struct drm_i915_private *dev_priv)
> > diff --git a/drivers/gpu/drm/i915/i915_vgpu.h b/drivers/gpu/drm/i915/i915_vgpu.h
> > index ebe1b7bced98..a919735fb6ce 100644
> > --- a/drivers/gpu/drm/i915/i915_vgpu.h
> > +++ b/drivers/gpu/drm/i915/i915_vgpu.h
> > @@ -26,7 +26,7 @@
> >
> > #include "i915_pvinfo.h"
> >
> > -void i915_check_vgpu(struct drm_i915_private *dev_priv);
> > +void i915_detect_vgpu(struct drm_i915_private *dev_priv);
> >
> > bool intel_vgpu_has_full_ppgtt(struct drm_i915_private *dev_priv);
> >
> > diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> > index 2bd602a41bb7..68d54e126d79 100644
> > --- a/drivers/gpu/drm/i915/intel_uncore.c
> > +++ b/drivers/gpu/drm/i915/intel_uncore.c
> > @@ -1650,8 +1650,6 @@ int intel_uncore_init_mmio(struct intel_uncore *uncore)
> > if (ret)
> > return ret;
> >
> > - i915_check_vgpu(i915);
> > -
> > if (INTEL_GEN(i915) > 5 && !intel_vgpu_active(i915))
> > uncore->flags |= UNCORE_HAS_FORCEWAKE;
Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
-Chris
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