Signed-off-by: Peng Hao <peng.hao2@xxxxxxxxxx> --- Documentation/virtual/kvm/00-INDEX | 2 ++ Documentation/virtual/kvm/coalesced-pio.txt | 15 +++++++++++++++ 2 files changed, 17 insertions(+) create mode 100644 Documentation/virtual/kvm/coalesced-pio.txt diff --git a/Documentation/virtual/kvm/00-INDEX b/Documentation/virtual/kvm/00-INDEX index 3492458..4b7a37b 100644 --- a/Documentation/virtual/kvm/00-INDEX +++ b/Documentation/virtual/kvm/00-INDEX @@ -9,6 +9,8 @@ arm - internal ABI between the kernel and HYP (for arm/arm64) cpuid.txt - KVM-specific cpuid leaves (x86). +coalesced-pio.txt + - KVM_CAP_COALESCED_PIO devices/ - KVM_CAP_DEVICE_CTRL userspace API. halt-polling.txt diff --git a/Documentation/virtual/kvm/coalesced-pio.txt b/Documentation/virtual/kvm/coalesced-pio.txt new file mode 100644 index 0000000..38dac11 --- /dev/null +++ b/Documentation/virtual/kvm/coalesced-pio.txt @@ -0,0 +1,15 @@ +Linux KVM Coalesced PIO: +============================ +Coalesced pio is base on coalesced mmio. When the write access to a port +of a device does a simple work (just like setting a register ID or address +index), then we can use coalesced pio. + +Setting a port as coalesced pio, the write access to the port don't need to +exit to userspace, and just record the value in shared coalesced ring in kernel. +Then following access to another port of the same device which relys on the +first port's setting or a read access to the first port will set the previous +write value of the first port firstly in usersapce according to the shared +coalesced ring. + +Coalesced pio can be used for rtc 0x70 port, pci-host config port, virtio-pci +config port and so on. -- 1.8.3.1
