Hi Wanghaibin,

On 06/09/2017 15:05, wanghaibin wrote:
> This patch fix the migrate restore tables failure.
> 
> The same scene, at the destination, the restore tables interface traversal 
> guest
> memory, and check the dte/ite is valid or not.
> If all dtes/ites are invalid, we will do try next one, and the last it will 
> take
> the 1 return value, but currently, it be treated as error. That's not correct.
There's indeed a bug here! In case all entries are invalid we shouldn't
return an error.

One solution could be to relax the error checking in scan_its_table()
and do not return 1 when the whole length has been scanned. This would
fix your issue.

drawback of that change:
at the moment we check the consistency of the entry data (next offset
field). At the moment if the next_offset points to an entry outside of
the table scope we are able to return an error (for top level tables).

Otherwise, if we want to keep that check, I think we would need to add a
bool *valid parameter to entry_fn_t. in scan_its_table() we would return
1 only if last fn() call returns valid and len <= 0.

Thanks

Eric

> 
> This patch try to fix this problem.
> 
> Signed-off-by: wanghaibin <wanghaibin.w...@huawei.com>
> ---
>  virt/kvm/arm/vgic/vgic-its.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index 5c20352..2c69aeb 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -2025,7 +2025,7 @@ static int vgic_its_restore_dte(struct vgic_its *its, 
> u32 id,
>               return PTR_ERR(dev);
>  
>       ret = vgic_its_restore_itt(its, dev);
> -     if (ret) {
> +     if (ret < 0) {
>               vgic_its_free_device(its->dev->kvm, dev);
>               return ret;
>       }
> @@ -2147,9 +2147,6 @@ static int vgic_its_restore_device_tables(struct 
> vgic_its *its)
>                                    vgic_its_restore_dte, NULL);
>       }
>  
> -     if (ret > 0)
> -             ret = -EINVAL;
> -
>       return ret;
>  }
>  
> 
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