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authorAlex Williamson <alex.williamson@redhat.com>2012-12-21 08:20:16 -0700
committerGleb Natapov <gleb@redhat.com>2012-12-23 10:17:38 +0200
commit116c14c0191f3378e6567af296529ac287e85aa2 (patch)
tree98b6f582d2d2f83da21918a95bfea48f1d37d84e /virt
parent871a069db9f29938071b3d214cb964980071ffbf (diff)
downloadlinux-116c14c0191f3378e6567af296529ac287e85aa2.tar.gz
kvm: Fix memory slot generation updates
Previous patch "kvm: Minor memory slot optimization" (b7f69c555ca43) overlooked the generation field of the memory slots. Re-using the original memory slots left us with with two slightly different memory slots with the same generation. To fix this, make update_memslots() take a new parameter to specify the last generation. This also makes generation management more explicit to avoid such problems in the future. Reported-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index bd31096e369..14cbae83be6 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -672,7 +672,8 @@ static void sort_memslots(struct kvm_memslots *slots)
slots->id_to_index[slots->memslots[i].id] = i;
}
-void update_memslots(struct kvm_memslots *slots, struct kvm_memory_slot *new)
+void update_memslots(struct kvm_memslots *slots, struct kvm_memory_slot *new,
+ u64 last_generation)
{
if (new) {
int id = new->id;
@@ -684,7 +685,7 @@ void update_memslots(struct kvm_memslots *slots, struct kvm_memory_slot *new)
sort_memslots(slots);
}
- slots->generation++;
+ slots->generation = last_generation + 1;
}
static int check_memory_region_flags(struct kvm_userspace_memory_region *mem)
@@ -819,7 +820,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
slot = id_to_memslot(slots, mem->slot);
slot->flags |= KVM_MEMSLOT_INVALID;
- update_memslots(slots, NULL);
+ update_memslots(slots, NULL, kvm->memslots->generation);
old_memslots = kvm->memslots;
rcu_assign_pointer(kvm->memslots, slots);
@@ -867,7 +868,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
memset(&new.arch, 0, sizeof(new.arch));
}
- update_memslots(slots, &new);
+ update_memslots(slots, &new, kvm->memslots->generation);
old_memslots = kvm->memslots;
rcu_assign_pointer(kvm->memslots, slots);
synchronize_srcu_expedited(&kvm->srcu);