Commit 8a08b9c7 authored by Cornelia Huck's avatar Cornelia Huck Committed by Christian Borntraeger

KVM: s390: usage hint for adapter mappings

The interface for adapter mappings was designed with code in mind
that maps each address only once; let's document this.

Otherwise, duplicate mappings are added to the list, which makes
the code ineffective and uses up the limited amount of mapping
needlessly.
Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent eaf2b656
...@@ -88,6 +88,8 @@ struct kvm_s390_io_adapter_req { ...@@ -88,6 +88,8 @@ struct kvm_s390_io_adapter_req {
perform a gmap translation for the guest address provided in addr, perform a gmap translation for the guest address provided in addr,
pin a userspace page for the translated address and add it to the pin a userspace page for the translated address and add it to the
list of mappings list of mappings
Note: A new mapping will be created unconditionally; therefore,
the calling code should avoid making duplicate mappings.
KVM_S390_IO_ADAPTER_UNMAP KVM_S390_IO_ADAPTER_UNMAP
release a userspace page for the translated address specified in addr release a userspace page for the translated address specified in addr
......
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