[PATCH V2] drm/i915/gvt: save RING_HEAD into vreg when vgpu switched out

[Zhenyu Wang]

On 2019.05.22 13:08:00 +0800, Xiaolin Zhang wrote:
> to save RING_HEAD into vgpu reg when vgpu switched out and report
> it's value back to guest.
> 
> v2: save RING_TAIL as well during vgpu mmio switch to meet ring_is_idle
> condition. (Fred Gao)
> v1: based on input from Weinan. (Weinan Li)
> 
> Fixes: 519a019491b8 ("drm/i915/hangcheck: Replace hangcheck.seqno with RING_HEAD")
> 
> Signed-off-by: Xiaolin Zhang <xiaolin.zhang at intel.com>
> ---
>  drivers/gpu/drm/i915/gvt/mmio_context.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/mmio_context.c b/drivers/gpu/drm/i915/gvt/mmio_context.c
> index 96e1edf..758a8b3 100644
> --- a/drivers/gpu/drm/i915/gvt/mmio_context.c
> +++ b/drivers/gpu/drm/i915/gvt/mmio_context.c
> @@ -457,6 +457,7 @@ static void switch_mmio(struct intel_vgpu *pre,
>  	struct intel_vgpu_submission *s;
>  	struct engine_mmio *mmio;
>  	u32 old_v, new_v;
> +	u32 ring_base;
>  
>  	dev_priv = pre ? pre->gvt->dev_priv : next->gvt->dev_priv;
>  	if (INTEL_GEN(dev_priv) >= 9)
> @@ -519,6 +520,14 @@ static void switch_mmio(struct intel_vgpu *pre,
>  				  old_v, new_v);
>  	}
>  
> +	if (pre) {
> +		ring_base = dev_priv->engine[ring_id]->mmio_base;
> +		vgpu_vreg_t(pre, RING_HEAD(ring_base)) =
> +				I915_READ_FW(RING_HEAD(ring_base));
> +		vgpu_vreg_t(pre, RING_TAIL(ring_base)) =
> +				I915_READ_FW(RING_TAIL(ring_base));
> +	}
> +

I think we should put these into save_ring_hw_state() to capture each
state change, instead of lagging until switch time?

>  	if (next)
>  		handle_tlb_pending_event(next, ring_id);
>  }
> -- 
> 2.7.4
> 
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> intel-gvt-dev at lists.freedesktop.org
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-- 
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