Hi Yan,
On 6/29/19 12:19 AM, Yan Zhao wrote:
> if an entry has non inclusive overlap with the notifier, print warning
> message and do not do notification for it.
>
> Out of scope mapping/unmapping would cause problem, as in below case:
>
> 1. initially there are two notifiers with ranges
> 0-0xfedfffff, 0xfef00000-0xffffffffffffffff,
> IOVAs from 0x3c000000 - 0x3c1fffff is in shadow page table.
>
> 2. in vfio, memory_region_register_iommu_notifier() is followed by
> memory_region_iommu_replay(), which will first call address space
> unmap,
> and walk and add back all entries in vtd shadow page table. e.g.
> (1) for notifier 0-0xfedfffff,
> IOVAs from 0 - 0xffffffff get unmapped,
> and IOVAs from 0x3c000000 - 0x3c1fffff get mapped
> (2) for notifier 0xfef00000-0xffffffffffffffff
> IOVAs from 0 - 0x7fffffffff get unmapped,
> but IOVAs from 0x3c000000 - 0x3c1fffff cannot get mapped back.
>
> Cc: Eric Auger <eric.au...@redhat.com>
> Cc: Peter Xu <pet...@redhat.com>
> Signed-off-by: Yan Zhao <yan.y.z...@intel.com>
Reviewed-by: Eric Auger <eric.au...@redhat.com>
Thanks
Eric
>
> ---
> v5:
> 1. still using warn_report instead of "assert"
> 2. returning at the end to refuse notification for entry which has non
> inclusive overlap with the notifier.
> 3. updated commit title and warning message.
>
> v4:
> 1. modified commit title
> 2. using "assert" instead of printing warning message
>
> v3:
> refined code style and message format
>
> v2:
> 1. added a local variable entry_end (Eric Auger)
> 2. using PRIx64 as format for address range in warning message
> (Eric Auger)
> ---
> memory.c | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/memory.c b/memory.c
> index 0a089a7..fe0d08d 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -1937,13 +1937,13 @@ void memory_region_notify_one(IOMMUNotifier *notifier,
> IOMMUTLBEntry *entry)
> {
> IOMMUNotifierFlag request_flags;
> + hwaddr entry_end = entry->iova + entry->addr_mask;
>
> /*
> * Skip the notification if the notification does not overlap
> * with registered range.
> */
> - if (notifier->start > entry->iova + entry->addr_mask ||
> - notifier->end < entry->iova) {
> + if (notifier->start > entry_end || notifier->end < entry->iova) {
> return;
> }
>
> @@ -1953,6 +1953,18 @@ void memory_region_notify_one(IOMMUNotifier *notifier,
> request_flags = IOMMU_NOTIFIER_UNMAP;
> }
>
> + if (entry->iova < notifier->start || entry_end > notifier->end) {
> + warn_report("IOMMUTLBEntry 0x%" PRIx64 " - 0x%" PRIx64
> + " has non inclusive overlap with notifier 0x%" PRIx64
> + " - 0x%" PRIx64 ". %s is not allowed."
> + " Try to divide it into smaller sections.",
> + entry->iova, entry_end,
> + notifier->start, notifier->end,
> + (request_flags == IOMMU_NOTIFIER_MAP) ?
> + "Mapping" : "Unmapping");
> + return;
> + }
> +
> if (notifier->notifier_flags & request_flags) {
> notifier->notify(notifier, entry);
> }
>
