[Intel-gfx] [PATCH v3 7/8] drm/i915/gvt: GVTg support context submission pvmmio optimization

[Christophe de Dinechin]

> On 13 Nov 2018, at 09:35, Xiaolin Zhang <xiaolin.zhang at intel.com> wrote:
> 
> implemented context submission pvmmio optimizaiton with GVTg.
> 
> GVTg to read context submission data (elsp_data) from the shared_page
> directly without trap cost to improve guest GPU peformrnace.
> 
> v0: RFC
> v1: rebase
> v2: rebase
> v3: report pv context submission cap and handle VGT_G2V_ELSP_SUBMIT
> g2v pv notification.
> 
> Cc: Zhenyu Wang <zhenyuw at linux.intel.com>
> Cc: Zhi Wang <zhi.a.wang at intel.com>
> Cc: Min He <min.he at intel.com>
> Cc: Fei Jiang <fei.jiang at intel.com>
> Cc: Zhipeng Gong <zhipeng.gong at intel.com>
> Cc: Hang Yuan <hang.yuan at intel.com>
> Cc: Zhiyuan Lv <zhiyuan.lv at intel.com>
> Signed-off-by: Xiaolin Zhang <xiaolin.zhang at intel.com>
> ---
> drivers/gpu/drm/i915/gvt/gvt.h      |  4 ++++
> drivers/gpu/drm/i915/gvt/handlers.c | 39 ++++++++++++++++++++++++++++++++++++-
> drivers/gpu/drm/i915/gvt/vgpu.c     |  2 ++
> 3 files changed, 44 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
> index e013962..c8bd1f3 100644
> --- a/drivers/gpu/drm/i915/gvt/gvt.h
> +++ b/drivers/gpu/drm/i915/gvt/gvt.h
> @@ -55,6 +55,10 @@
> #define _vgtif_reg(x) \
> 	(VGT_PVINFO_PAGE + offsetof(struct vgt_if, x))
> 
> +#define VGPU_PVMMIO(vgpu, level)	\
> +	((vgpu_vreg_t(vgpu, vgtif_reg(pvmmio_caps)) & level) \
> +			&& vgpu->shared_page_enabled)
> +
> enum {
> 	INTEL_GVT_HYPERVISOR_XEN = 0,
> 	INTEL_GVT_HYPERVISOR_KVM,
> diff --git a/drivers/gpu/drm/i915/gvt/handlers.c b/drivers/gpu/drm/i915/gvt/handlers.c
> index 16ef41b..1659bd1 100644
> --- a/drivers/gpu/drm/i915/gvt/handlers.c
> +++ b/drivers/gpu/drm/i915/gvt/handlers.c
> @@ -1180,12 +1180,46 @@ static int pvinfo_mmio_read(struct intel_vgpu *vgpu, unsigned int offset,
> 	return 0;
> }
> 
> +static int intel_vgpu_g2v_pv_elsp_submit(struct intel_vgpu *vgpu)
> +{
> +	int ring_id;
> +	struct intel_vgpu_execlist *execlist;
> +	u32 elsp_data[4 * I915_NUM_ENGINES];
> +	u32 elsp_data_off;
> +	u32 ring_id_off;
> +	int ret = -EINVAL;
> +
> +	if (!VGPU_PVMMIO(vgpu, PVMMIO_ELSP_SUBMIT))
> +		return ret;
> +
> +	ring_id_off = offsetof(struct gvt_shared_page, ring_id);
> +	if (intel_gvt_read_shared_page(vgpu, ring_id_off, &ring_id, 4))
> +		return ret;
> +
> +	if (WARN_ON(ring_id < 0 || ring_id >= I915_NUM_ENGINES))
> +		return ret;
> +
> +	elsp_data_off = offsetof(struct gvt_shared_page, elsp_data);
> +	if (intel_gvt_read_shared_page(vgpu, elsp_data_off, &elsp_data,
> +			16 * I915_NUM_ENGINES))
> +		return ret;
> +
> +	execlist = &vgpu->submission.execlist[ring_id];
> +	execlist->elsp_dwords.data[3] = elsp_data[ring_id * 4 + 2];
> +	execlist->elsp_dwords.data[2] = elsp_data[ring_id * 4 + 3];
> +	execlist->elsp_dwords.data[1] = elsp_data[ring_id * 4 + 0];
> +	execlist->elsp_dwords.data[0] = elsp_data[ring_id * 4 + 1];

It wold be nice to have a named macro to express the intent behind this word swapping.
It’s probably not the only place where this happens?

> +
> +	return intel_vgpu_submit_execlist(vgpu, ring_id);
> +}
> +
> static int handle_g2v_notification(struct intel_vgpu *vgpu, int notification)
> {
> 	intel_gvt_gtt_type_t root_entry_type = GTT_TYPE_PPGTT_ROOT_L4_ENTRY;
> 	struct intel_vgpu_mm *mm;
> 	u64 *pdps;
> 	unsigned long gfn;
> +	int ret = 0;
> 
> 	pdps = (u64 *)&vgpu_vreg64_t(vgpu, vgtif_reg(pdp[0]));
> 
> @@ -1204,6 +1238,9 @@ static int handle_g2v_notification(struct intel_vgpu *vgpu, int notification)
> 		if (intel_gvt_hypervisor_is_valid_gfn(vgpu, gfn))
> 			vgpu->shared_page_enabled = true;
> 		break;
> +	case VGT_G2V_ELSP_SUBMIT:
> +		ret = intel_vgpu_g2v_pv_elsp_submit(vgpu);
> +		break;
> 	case VGT_G2V_EXECLIST_CONTEXT_CREATE:
> 	case VGT_G2V_EXECLIST_CONTEXT_DESTROY:
> 	case 1:	/* Remove this in guest driver. */
> @@ -1211,7 +1248,7 @@ static int handle_g2v_notification(struct intel_vgpu *vgpu, int notification)
> 	default:
> 		gvt_vgpu_err("Invalid PV notification %d\n", notification);
> 	}
> -	return 0;
> +	return ret;
> }
> 
> static int send_display_ready_uevent(struct intel_vgpu *vgpu, int ready)
> diff --git a/drivers/gpu/drm/i915/gvt/vgpu.c b/drivers/gpu/drm/i915/gvt/vgpu.c
> index 40aaae8..f98b591 100644
> --- a/drivers/gpu/drm/i915/gvt/vgpu.c
> +++ b/drivers/gpu/drm/i915/gvt/vgpu.c
> @@ -49,6 +49,8 @@ void populate_pvinfo_page(struct intel_vgpu *vgpu)
> 	vgpu_vreg_t(vgpu, vgtif_reg(vgt_caps)) |= VGT_CAPS_HUGE_GTT;
> 	vgpu_vreg_t(vgpu, vgtif_reg(vgt_caps)) |= VGT_CAPS_PVMMIO;
> 
> +	vgpu_vreg_t(vgpu, vgtif_reg(pvmmio_caps)) = PVMMIO_ELSP_SUBMIT;
> +
> 	vgpu_vreg_t(vgpu, vgtif_reg(avail_rs.mappable_gmadr.base)) =
> 		vgpu_aperture_gmadr_base(vgpu);
> 	vgpu_vreg_t(vgpu, vgtif_reg(avail_rs.mappable_gmadr.size)) =
> -- 
> 2.7.4
> 
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