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-rw-r--r--include/linux/kvm_host.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 401439bb21e3..b0b38744c4b0 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -963,6 +963,15 @@ static inline struct kvm_io_bus *kvm_get_bus(struct kvm *kvm, enum kvm_bus idx)
static inline struct kvm_vcpu *kvm_get_vcpu(struct kvm *kvm, int i)
{
int num_vcpus = atomic_read(&kvm->online_vcpus);
+
+ /*
+ * Explicitly verify the target vCPU is online, as the anti-speculation
+ * logic only limits the CPU's ability to speculate, e.g. given a "bad"
+ * index, clamping the index to 0 would return vCPU0, not NULL.
+ */
+ if (i >= num_vcpus)
+ return NULL;
+
i = array_index_nospec(i, num_vcpus);
/* Pairs with smp_wmb() in kvm_vm_ioctl_create_vcpu. */