[PATCH v4 13/14] drm/i915/gvt: Fix error handling in ppgtt_populate_spt_by_guest_entry

[Zhenyu Wang]

On 2018.05.04 17:50:39 +0800, changbin.du at intel.com wrote:
> From: Changbin Du <changbin.du at intel.com>
> 
> Don't forget to free allocated spt if shadowing failed.
> 
> Signed-off-by: Changbin Du <changbin.du at intel.com>
> ---
>  drivers/gpu/drm/i915/gvt/gtt.c | 31 ++++++++++++++++++++-----------
>  1 file changed, 20 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
> index 2bf85be..4af6fee3 100644
> --- a/drivers/gpu/drm/i915/gvt/gtt.c
> +++ b/drivers/gpu/drm/i915/gvt/gtt.c
> @@ -912,10 +912,17 @@ static void ppgtt_get_spt(struct intel_vgpu_ppgtt_spt *spt)
>  	int v = atomic_read(&spt->refcount);
>  
>  	trace_spt_refcount(spt->vgpu->id, "inc", spt, v, (v + 1));
> -
>  	atomic_inc(&spt->refcount);
>  }
>  
> +static int ppgtt_put_spt(struct intel_vgpu_ppgtt_spt *spt)
> +{
> +	int v = atomic_read(&spt->refcount);
> +
> +	trace_spt_refcount(spt->vgpu->id, "dec", spt, v, (v - 1));
> +	return atomic_dec_return(&spt->refcount);
> +}

Use atomic_fetch_dec()

> +
>  static int ppgtt_invalidate_spt(struct intel_vgpu_ppgtt_spt *spt);
>  
>  static int ppgtt_invalidate_spt_by_shadow_entry(struct intel_vgpu *vgpu,
> @@ -967,14 +974,11 @@ static int ppgtt_invalidate_spt(struct intel_vgpu_ppgtt_spt *spt)
>  	struct intel_gvt_gtt_entry e;
>  	unsigned long index;
>  	int ret;
> -	int v = atomic_read(&spt->refcount);
>  
>  	trace_spt_change(spt->vgpu->id, "die", spt,
>  			spt->guest_page.gfn, spt->shadow_page.type);
>  
> -	trace_spt_refcount(spt->vgpu->id, "dec", spt, v, (v - 1));
> -
> -	if (atomic_dec_return(&spt->refcount) > 0)
> +	if (ppgtt_put_spt(spt) > 0)
>  		return 0;
>  
>  	for_each_present_shadow_entry(spt, &e, index) {
> @@ -1056,8 +1060,10 @@ static struct intel_vgpu_ppgtt_spt *ppgtt_populate_spt_by_guest_entry(
>  			gvt_dbg_mm("reshadow PDE since ips changed\n");
>  			clear_page(spt->shadow_page.vaddr);
>  			ret = ppgtt_populate_spt(spt);
> -			if (ret)
> -				goto fail;
> +			if (ret) {
> +				ppgtt_put_spt(spt);
> +				goto err;
> +			}
>  		}
>  	} else {
>  		int type = get_next_pt_type(we->type);
> @@ -1065,22 +1071,25 @@ static struct intel_vgpu_ppgtt_spt *ppgtt_populate_spt_by_guest_entry(
>  		spt = ppgtt_alloc_spt_gfn(vgpu, type, ops->get_pfn(we), ips);
>  		if (IS_ERR(spt)) {
>  			ret = PTR_ERR(spt);
> -			goto fail;
> +			goto err;
>  		}
>  
>  		ret = intel_vgpu_enable_page_track(vgpu, spt->guest_page.gfn);
>  		if (ret)
> -			goto fail;
> +			goto err_free_spt;
>  
>  		ret = ppgtt_populate_spt(spt);
>  		if (ret)
> -			goto fail;
> +			goto err_free_spt;
>  
>  		trace_spt_change(vgpu->id, "new", spt, spt->guest_page.gfn,
>  				 spt->shadow_page.type);
>  	}
>  	return spt;
> -fail:
> +
> +err_free_spt:
> +	ppgtt_free_spt(spt);
> +err:
>  	gvt_vgpu_err("fail: shadow page %p guest entry 0x%llx type %d\n",
>  		     spt, we->val64, we->type);
>  	return ERR_PTR(ret);
> -- 
> 2.7.4
> 
> _______________________________________________
> intel-gvt-dev mailing list
> intel-gvt-dev at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev

-- 
Open Source Technology Center, Intel ltd.

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