[PATCH] drm/i915/gvt: clear the vGPU reset logic

[Christophe de Dinechin]

> On 20 Feb 2017, at 03:01, Ping Gao <ping.a.gao at intel.com> wrote:
> 
> Releasing shadow PPGTT pages is not enough when vGPU reset, the
> guest page table tracking data should has same life-cycle with
> all the shadow PPGTT pages; Otherwise there is no chance to
> re-shadow the PPGTT pages without free the guest page table
> tracking data.
> 
> This patch clear the PPGTT reset logic and make the vGPU reset in
> working order.
> 
> Signed-off-by: Ping Gao <ping.a.gao at intel.com>
> ---
> drivers/gpu/drm/i915/gvt/gtt.c | 33 ++++++++++++++++++++++++++++++++-
> 1 file changed, 32 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
> index 28c9234..77fe681 100644
> --- a/drivers/gpu/drm/i915/gvt/gtt.c
> +++ b/drivers/gpu/drm/i915/gvt/gtt.c
> @@ -2309,6 +2309,36 @@ void intel_vgpu_reset_ggtt(struct intel_vgpu *vgpu)
> }
> 
> /**
> + * intel_vgpu_reset_ppgtt - free all the ppgtt entries and the
> + * guest page table tracking data.
> + * @vgpu: a vGPU
> + *
> + * This function is called during vGPU reset.
> + *
> + */
> +static void intel_vgpu_reset_ppgtt(struct intel_vgpu *vgpu)
> +{
> +	struct list_head *pos, *n;
> +	struct intel_vgpu_mm *mm;
> +
> +	ppgtt_free_all_shadow_page(vgpu);
> +
> +	/* The guest page table tracking data should free also after
> +	 * free all the shadow pages, otherwise there is no chance
> +	 * to create those shadow pages again when it's need.
> +	 */

I don’t understand the comment as written. I believe you mean that the code creating the shadow pages does not trigger if there is some page table tracking data, so you need to clear that data so that the shadow pages are subsequently re-created. Is that right?

If that’s the case, I suggest something like:

Shadow pages are only created when there is no page table tracking data, so remove page tracking data after removing the shadow pages.

> +	list_for_each_safe(pos, n, &vgpu->gtt.mm_list_head) {
> +		mm = container_of(pos, struct intel_vgpu_mm, list);
> +		if (mm->type == INTEL_GVT_MM_PPGTT) {
> +			vgpu->gvt->gtt.mm_free_page_table(mm);
> +			list_del(&mm->list);
> +			list_del(&mm->lru_list);
> +			kfree(mm);
> +		}
> +	}
> +}
> +
> +/**
>  * intel_vgpu_reset_gtt - reset the all GTT related status
>  * @vgpu: a vGPU
>  * @dmlr: true for vGPU Device Model Level Reset, false for GT Reset
> @@ -2321,7 +2351,8 @@ void intel_vgpu_reset_gtt(struct intel_vgpu *vgpu, bool dmlr)
> {
> 	int i;
> 
> -	ppgtt_free_all_shadow_page(vgpu);
> +	intel_vgpu_reset_ppgtt(vgpu);
> +
> 	if (!dmlr)
> 		return;
> 
> -- 
> 2.7.4
> 
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