[PATCH] drm/i915/gvt: addressed vGPU hang during OCL conformance test

[Zhenyu Wang]

Better change title on the driver issue this fixes.

On 2019.07.17 22:06:00 +0800, Xiaolin Zhang wrote:
> GPU hang observed during the guest OCL conformance test which is caused
> by THP GTT feature used durning the test.
> 
> it was observed the same GFN with different size (4K and 2M) requested
> from the quest in GVT. so during the guest page dma map stage, it is
> required to unmap first with orginal size and then remap again with
> requested size.
> 
> Signed-off-by: Xiaolin Zhang <xiaolin.zhang at intel.com>
> ---
>  drivers/gpu/drm/i915/gvt/kvmgt.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index a68addf..4a7cf86 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -1911,6 +1911,18 @@ static int kvmgt_dma_map_guest_page(unsigned long handle, unsigned long gfn,
>  		ret = __gvt_cache_add(info->vgpu, gfn, *dma_addr, size);
>  		if (ret)
>  			goto err_unmap;
> +	} else if (entry->size != size) {
> +		/* the same gfn with different size: unmap and re-map */
> +		gvt_dma_unmap_page(vgpu, gfn, entry->dma_addr, entry->size);
> +		__gvt_cache_remove_entry(vgpu, entry);
> +
> +		ret = gvt_dma_map_page(vgpu, gfn, dma_addr, size);
> +		if (ret)
> +			goto err_unlock;
> +
> +		ret = __gvt_cache_add(info->vgpu, gfn, *dma_addr, size);
> +		if (ret)
> +			goto err_unmap;

looks good to me. This should deserve to cc stable kernel.

Reviewed-by: Zhenyu Wang <zhenyuw at linux.intel.com>

>  	} else {
>  		kref_get(&entry->ref);
>  		*dma_addr = entry->dma_addr;
> -- 
> 1.8.3.1
> 
> _______________________________________________
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> intel-gvt-dev at lists.freedesktop.org
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-- 
Open Source Technology Center, Intel ltd.

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