KVM: fix spectrev1 gadgets

[ Upstream commit 1d487e9bf8ba66a7174c56a0029c54b1eca8f99c ]

These were found with smatch, and then generalized when applicable.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

1 files changed, 6 insertions, 4 deletions

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 23c242a7ac52..30efb3663892 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -28,6 +28,7 @@
 #include <linux/irqbypass.h>
 #include <linux/swait.h>
 #include <linux/refcount.h>
+#include <linux/nospec.h>
 #include <asm/signal.h>
 
 #include <linux/kvm.h>
@@ -491,10 +492,10 @@ 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)
 {
-	/* Pairs with smp_wmb() in kvm_vm_ioctl_create_vcpu, in case
-	 * the caller has read kvm->online_vcpus before (as is the case
-	 * for kvm_for_each_vcpu, for example).
-	 */
+	int num_vcpus = atomic_read(&kvm->online_vcpus);
+	i = array_index_nospec(i, num_vcpus);
+
+	/* Pairs with smp_wmb() in kvm_vm_ioctl_create_vcpu.  */
 	smp_rmb();
 	return kvm->vcpus[i];
 }
@@ -578,6 +579,7 @@ void kvm_put_kvm(struct kvm *kvm);
 
 static inline struct kvm_memslots *__kvm_memslots(struct kvm *kvm, int as_id)
 {
+	as_id = array_index_nospec(as_id, KVM_ADDRESS_SPACE_NUM);
 	return srcu_dereference_check(kvm->memslots[as_id], &kvm->srcu,
 			lockdep_is_held(&kvm->slots_lock) ||
 			!refcount_read(&kvm->users_count));