[PATCH RFC 02/10] KVM: Allow reading memslots while holding slots_arch_lock

[Marco Elver]

kvm_swap_active_memslots() updates kvm->memslots[as_id] while holding both
kvm->slots_lock and kvm->slots_arch_lock. Holding either lock guarantees
that memslots cannot be concurrently modified.

Allow reading memslots in __kvm_memslots() when kvm->slots_arch_lock is
held.

Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
---
 include/linux/kvm_host.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 03bfc92864b6..5ed8260ef01f 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1089,6 +1089,7 @@ static inline struct kvm_memslots *__kvm_memslots(struct kvm *kvm, int as_id)
 	as_id = array_index_nospec(as_id, KVM_MAX_NR_ADDRESS_SPACES);
 	return srcu_dereference_check(kvm->memslots[as_id], &kvm->srcu,
 			lockdep_is_held(&kvm->slots_lock) ||
+			lockdep_is_held(&kvm->slots_arch_lock) ||
 			!refcount_read(&kvm->users_count));
 }
 
-- 
2.55.0.1003.g10538fe699-goog