documentation/kvm: additional explanations on KVM_SET_BOOT_CPU_ID

The ioctl KVM_SET_BOOT_CPU_ID fails when called after vcpu creation.
Add this explanation in the documentation.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20210319091650.11967-1-eesposit@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 2898d3e..307f2fc 100644 (file)
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -1495,7 +1495,8 @@ Fails if any VCPU has already been created.
 
 Define which vcpu is the Bootstrap Processor (BSP).  Values are the same
 as the vcpu id in KVM_CREATE_VCPU.  If this ioctl is not called, the default
-is vcpu 0.
+is vcpu 0. This ioctl has to be called before vcpu creation,
+otherwise it will return EBUSY error.
 
 
 4.42 KVM_GET_XSAVE