diff options
| author | Jason Wang <jasowang@redhat.com> | 2015-09-15 14:41:59 +0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2015-10-01 15:06:31 +0200 |
| commit | e9ea5069d9e569c32ab913c39467df32e056b3a7 (patch) | |
| tree | 1e3e34946e2875564aa7a85a454f851d1575dac8 /Documentation | |
| parent | 931c33b178b091cced2a6b3f57f04655f8ff5207 (diff) | |
kvm: add capability for any-length ioeventfds
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/virtual/kvm/api.txt | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index e3e9c41721a2..34cc068e81ea 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -1604,7 +1604,7 @@ provided event instead of triggering an exit. struct kvm_ioeventfd { __u64 datamatch; __u64 addr; /* legal pio/mmio address */ - __u32 len; /* 1, 2, 4, or 8 bytes */ + __u32 len; /* 0, 1, 2, 4, or 8 bytes */ __s32 fd; __u32 flags; __u8 pad[36]; @@ -1627,6 +1627,10 @@ to the registered address is equal to datamatch in struct kvm_ioeventfd. For virtio-ccw devices, addr contains the subchannel id and datamatch the virtqueue index. +With KVM_CAP_IOEVENTFD_ANY_LENGTH, a zero length ioeventfd is allowed, and +the kernel will ignore the length of guest write and may get a faster vmexit. +The speedup may only apply to specific architectures, but the ioeventfd will +work anyway. 4.60 KVM_DIRTY_TLB |