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| author | Cornelia Huck <cornelia.huck@de.ibm.com> | 2016-01-26 10:48:59 +0100 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2016-02-10 13:12:56 +0100 |
| commit | 8a08b9c7379dc881ff5f00c086877353888a982f (patch) | |
| tree | 8bafb02cc1ccc18f884f6b70a39faea51d0d0643 /Documentation/virtual | |
| parent | eaf2b656cf14c2088b1b3193742c40a399b1df14 (diff) | |
| download | lwn-8a08b9c7379dc881ff5f00c086877353888a982f.tar.gz lwn-8a08b9c7379dc881ff5f00c086877353888a982f.zip | |
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: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'Documentation/virtual')
| -rw-r--r-- | Documentation/virtual/kvm/devices/s390_flic.txt | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/devices/s390_flic.txt b/Documentation/virtual/kvm/devices/s390_flic.txt index d1ad9d5cae46..e3e314cb83e8 100644 --- a/Documentation/virtual/kvm/devices/s390_flic.txt +++ b/Documentation/virtual/kvm/devices/s390_flic.txt @@ -88,6 +88,8 @@ struct kvm_s390_io_adapter_req { perform a gmap translation for the guest address provided in addr, pin a userspace page for the translated address and add it to the 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 release a userspace page for the translated address specified in addr |