The EAGAIN errno is returned when an application processor was
blocked because of an uninitialized MP state [1].

[1] commit c5ec153402b6 ("KVM: enable in-kernel APIC INIT/SIPI handling")

Signed-off-by: Changyuan Lyu <changyuan.lv@gmail.com>
---
 Documentation/virt/kvm/api.rst | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 7025b3751027..fccdbb366770 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -370,6 +370,8 @@ Errors:
 
   =======    ==============================================================
   EINTR      an unmasked signal is pending
+  EAGAIN     the vcpu is an application processor (AP) and had not received
+             an INIT signal [x86]
   ENOEXEC    the vcpu hasn't been initialized or the guest tried to execute
              instructions from device memory (arm64)
   ENOSYS     data abort outside memslots with no syndrome info and
-- 
2.43.0.472.g3155946c3a-goog