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KVM: Fix user memslot overlap check 

Prior to memory slot sorting this loop compared all of the user memory
slots for overlap with new entries.  With memory slot sorting, we're
just checking some number of entries in the array that may or may not
be user slots.  Instead, walk all the slots with kvm_for_each_memslot,
which has the added benefit of terminating early when we hit the first
empty slot, and skip comparison to private slots.

Cc: stable@vger.kernel.org
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Alex Williamson 2012-11-29 14:07:59 -07:00 committed by Marcelo Tosatti
parent 5a560f8b5e
commit 5419369ed6
1 changed files with 5 additions and 8 deletions
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13
virt/kvm/kvm_main.c
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@ -714,8 +714,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
int r;
gfn_t base_gfn;
unsigned long npages;
unsigned long i;
struct kvm_memory_slot *memslot;
struct kvm_memory_slot *memslot, *slot;
struct kvm_memory_slot old, new;
struct kvm_memslots *slots, *old_memslots;
@ -766,13 +765,11 @@ int __kvm_set_memory_region(struct kvm *kvm,
/* Check for overlaps */
r = -EEXIST;
for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
struct kvm_memory_slot *s = &kvm->memslots->memslots[i];
if (s == memslot || !s->npages)
kvm_for_each_memslot(slot, kvm->memslots) {
if (slot->id >= KVM_MEMORY_SLOTS || slot == memslot)
continue;
if (!((base_gfn + npages <= s->base_gfn) ||
(base_gfn >= s->base_gfn + s->npages)))
if (!((base_gfn + npages <= slot->base_gfn) ||
(base_gfn >= slot->base_gfn + slot->npages)))
goto out_free;
}