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memory: assert on out of scope notification 

It is wrong for an entry to have parts out of scope of notifier's range.
assert this condition.

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.auger@redhat.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>

Message-Id: <1561432878-13754-1-git-send-email-yan.y.zhao@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Yan Zhao 2019-06-25 11:21:18 +08:00 committed by Paolo Bonzini
parent e502fe96ac
commit 03c7140c1a
1 changed files with 4 additions and 2 deletions
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6
memory.c
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@ -1942,16 +1942,18 @@ 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;
}
assert(entry->iova >= notifier->start && entry_end <= notifier->end);
if (entry->perm & IOMMU_RW) {
request_flags = IOMMU_NOTIFIER_MAP;
} else {