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Commit 5419369e authored by Alex Williamson's avatar Alex Williamson Committed by Marcelo Tosatti
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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: default avatarAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 5a560f8b

virt/kvm/kvm_main.c

+5 −8
Original line number Diff line number Diff line
@@ -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;

	}