Re: [RFC v8 5/5] memory: Skip bad range assertion if notifier is DEVIOTLB type

[Auger Eric <eric.auger@redhat.com>]

Hi Eugenio,

On 9/1/20 4:26 PM, Eugenio Pérez wrote:
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Please could you explain in the commit message why you need to remove
the assert()? I know you described the assert() in the cover letter but
the commit msg is the one that remains.
> ---
>  softmmu/memory.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/softmmu/memory.c b/softmmu/memory.c
> index 09b3443eac..3ee99b4dc0 100644
> --- a/softmmu/memory.c
> +++ b/softmmu/memory.c
> @@ -1895,6 +1895,7 @@ void memory_region_notify_iommu_one(IOMMUNotifier *notifier,
>  {
>      IOMMUTLBEntry *entry = &event->entry;
>      hwaddr entry_end = entry->iova + entry->addr_mask;
> +    IOMMUTLBEntry tmp = *entry;
>  
>      /*
>       * Skip the notification if the notification does not overlap
> @@ -1904,10 +1905,18 @@ void memory_region_notify_iommu_one(IOMMUNotifier *notifier,
>          return;
>      }
>  
> -    assert(entry->iova >= notifier->start && entry_end <= notifier->end);
> +    if (notifier->notifier_flags & IOMMU_NOTIFIER_DEVIOTLB) {
> +        /* Crop (iova, addr_mask) to range */
> +        tmp.iova = MAX(tmp.iova, notifier->start);
> +        tmp.addr_mask = MIN(entry_end, notifier->end) - tmp.iova;
> +        /* Confirm no underflow */
> +        assert(MIN(entry_end, notifier->end) >= tmp.iova);
> +    } else {
> +        assert(entry->iova >= notifier->start && entry_end <= notifier->end);
> +    }
>  
>      if (event->type & notifier->notifier_flags) {
> -        notifier->notify(notifier, entry);
> +        notifier->notify(notifier, &tmp);
>      }
>  }
>  
> 
Thanks

Eric