On 2018.11.13 16:35:14 +0800, Xiaolin Zhang wrote:
> To enable pvmmio feature, we need to prepare one 4K shared page
> which will be accessed by both guest and backend i915 driver used for
> data exchagne.
> 
> the layout of shared_page also defined as well in this patch.
> 
> guest i915 will allocate one page memory and then pass this page's physical
> address to backend i915 driver through PVINFO register so that backend i915
> driver can access this shared page without hypeviser trap cost
> for shared data exchagne via hyperviser read_gpa functionality.
> 
> v0: RFC
> v1: addressed RFC comment to move both shared_page_lock and shared_page
> to i915_virtual_gpu structure
> v2: packed i915_virtual_gpu structure
> v3: added SHARED_PAGE_SETUP g2v notification for pv shared_page setup
> 
> Cc: Zhenyu Wang <[email protected]>
> Cc: Zhi Wang <[email protected]>
> Cc: Chris Wilson <[email protected]>
> Cc: Joonas Lahtinen <[email protected]>
> Cc: He Min <[email protected]>
> Cc: Jiang Fei <[email protected]>
> Cc: Gong Zhipeng <[email protected]>
> Cc: Yuan Hang <[email protected]>
> Cc: Zhiyuan Lv <[email protected]>
> Signed-off-by: Xiaolin Zhang <[email protected]>
> ---
>  drivers/gpu/drm/i915/i915_drv.c    |  2 ++
>  drivers/gpu/drm/i915/i915_drv.h    |  4 +++-
>  drivers/gpu/drm/i915/i915_pvinfo.h | 29 ++++++++++++++++++++++++++++-
>  drivers/gpu/drm/i915/i915_vgpu.c   | 23 +++++++++++++++++++++++
>  4 files changed, 56 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index baac35f..557ab67 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -987,6 +987,8 @@ static void i915_mmio_cleanup(struct drm_i915_private 
> *dev_priv)
>  
>       intel_teardown_mchbar(dev_priv);
>       pci_iounmap(pdev, dev_priv->regs);
> +     if (intel_vgpu_active(dev_priv) && dev_priv->vgpu.shared_page)
> +             free_page((unsigned long)dev_priv->vgpu.shared_page);
>  }
>  
>  /**
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 7b2d7cb..d7a972f 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1345,7 +1345,9 @@ struct i915_virtual_gpu {
>       bool active;
>       u32 caps;
>       u32 pv_caps;
> -};
> +     spinlock_t shared_page_lock;
> +     struct gvt_shared_page *shared_page;
> +} __packed;
>  
>  /* used in computing the new watermarks state */
>  struct intel_wm_config {
> diff --git a/drivers/gpu/drm/i915/i915_pvinfo.h 
> b/drivers/gpu/drm/i915/i915_pvinfo.h
> index 78a4b9c..aa5eebc 100644
> --- a/drivers/gpu/drm/i915/i915_pvinfo.h
> +++ b/drivers/gpu/drm/i915/i915_pvinfo.h
> @@ -24,6 +24,8 @@
>  #ifndef _I915_PVINFO_H_
>  #define _I915_PVINFO_H_
>  
> +#include "i915_gem.h"
> +
>  /* The MMIO offset of the shared info between guest and host emulator */
>  #define VGT_PVINFO_PAGE      0x78000
>  #define VGT_PVINFO_SIZE      0x1000
> @@ -46,9 +48,29 @@ enum vgt_g2v_type {
>       VGT_G2V_PPGTT_L4_PAGE_TABLE_DESTROY,
>       VGT_G2V_EXECLIST_CONTEXT_CREATE,
>       VGT_G2V_EXECLIST_CONTEXT_DESTROY,
> +     VGT_G2V_SHARED_PAGE_SETUP,
>       VGT_G2V_MAX,
>  };
>  
> +struct pv_ppgtt_update {
> +     u64 pdp;
> +     u64 start;
> +     u64 length;
> +     u32 cache_level;
> +};
> +
> +/*
> + * shared page(4KB) between gvt and VM, could be allocated by guest driver
> + * or a fixed location in PCI bar 0 region
> + */
> +struct gvt_shared_page {
> +     u32 reg_addr;
> +     u32 elsp_data[I915_NUM_ENGINES * 4];

You can't rely on I915_NUM_ENGINES, which may be changed so that would
cause incompatibility in shared page definition.

> +     u32 ring_id;
> +     u32 disable_irq;
> +     struct pv_ppgtt_update pv_ppgtt;
> +};
> +
>  /*
>   * VGT capabilities type
>   */
> @@ -121,7 +143,12 @@ struct vgt_if {
>  
>       u32 pvmmio_caps;
>  
> -     u32  rsv7[0x200 - 25];    /* pad to one page */
> +     struct {
> +             u32 lo;
> +             u32 hi;
> +     } shared_page_gpa;
> +
> +     u32  rsv7[0x200 - 27];    /* pad to one page */
>  } __packed;
>  
>  #define vgtif_reg(x) \
> diff --git a/drivers/gpu/drm/i915/i915_vgpu.c 
> b/drivers/gpu/drm/i915/i915_vgpu.c
> index 219c7c0..63f70bf 100644
> --- a/drivers/gpu/drm/i915/i915_vgpu.c
> +++ b/drivers/gpu/drm/i915/i915_vgpu.c
> @@ -63,6 +63,7 @@ void i915_check_vgpu(struct drm_i915_private *dev_priv)
>       u64 magic;
>       u16 version_major;
>       u32 gvt_caps;
> +     u64 gpa;
>  
>       BUILD_BUG_ON(sizeof(struct vgt_if) != VGT_PVINFO_SIZE);
>  
> @@ -95,6 +96,28 @@ void i915_check_vgpu(struct drm_i915_private *dev_priv)
>       if (!dev_priv->vgpu.pv_caps)
>               return;
>  
> +     dev_priv->vgpu.shared_page =  (struct gvt_shared_page *)
> +                     get_zeroed_page(GFP_KERNEL);
> +     if (!dev_priv->vgpu.shared_page) {
> +             DRM_ERROR("out of memory for shared page memory\n");
> +             return;
> +     }
> +     gpa = __pa(dev_priv->vgpu.shared_page);
> +     __raw_i915_write32(dev_priv, vgtif_reg(shared_page_gpa.lo),
> +                     lower_32_bits(gpa));
> +     __raw_i915_write32(dev_priv, vgtif_reg(shared_page_gpa.hi),
> +                     upper_32_bits(gpa));
> +     if (gpa != __raw_i915_read64(dev_priv,
> +                     vgtif_reg(shared_page_gpa))) {
> +             DRM_ERROR("vgpu: passed shared_page_gpa failed\n");
> +             free_page((unsigned long)dev_priv->vgpu.shared_page);
> +             dev_priv->vgpu.pv_caps = 0;
> +             __raw_i915_write32(dev_priv, vgtif_reg(pvmmio_caps), 0);
> +             return;
> +     }
> +     __raw_i915_write32(dev_priv, vgtif_reg(g2v_notify),
> +                     VGT_G2V_SHARED_PAGE_SETUP);
> +     spin_lock_init(&dev_priv->vgpu.shared_page_lock);
>  
>       DRM_INFO("Virtual GPU for Intel GVT-g detected with pvmmio 0x%x\n",
>                       dev_priv->vgpu.pv_caps);
> -- 
> 2.7.4
> 
> _______________________________________________
> intel-gvt-dev mailing list
> [email protected]
> https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev

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