The current MMIO transport layer uses a single, dedicated interrupt signal, which brings performance penalty. Add a feature bit (40) for introducing MSI capability.
Co-developed-by: Chao Peng <chao.p.p...@linux.intel.com> Signed-off-by: Chao Peng <chao.p.p...@linux.intel.com> Co-developed-by: Liu Jiang <ge...@linux.alibaba.com> Signed-off-by: Liu Jiang <ge...@linux.alibaba.com> Co-developed-by: Zha Bin <zha...@linux.alibaba.com> Signed-off-by: Zha Bin <zha...@linux.alibaba.com> Signed-off-by: Jing Liu <jing2....@linux.intel.com> --- content.tex | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/content.tex b/content.tex index 5881253..ff151ba 100644 --- a/content.tex +++ b/content.tex @@ -5840,6 +5840,9 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits} \item[VIRTIO_F_MMIO_NOTIFICATION(39)] This feature indicates that the device supports enhanced notification mechanism on MMIO transport layer. + \item[VIRTIO_F_MMIO_MSI(40)] This feature indicates that the + device supports Message Signal Interrupts (MSI) mechanism on + MMIO transport layer. \drivernormative{\section}{Reserved Feature Bits}{Reserved Feature Bits} @@ -5875,6 +5878,10 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits} A driver SHOULD accept VIRTIO_F_MMIO_NOTIFICATION if it is offered. +A driver SHOULD accept VIRTIO_F_MMIO_MSI if it is offered. +If VIRTIO_F_MMIO_MSI has been negotiated, a driver MUST try to +set up MSI at first priority. + \devicenormative{\section}{Reserved Feature Bits}{Reserved Feature Bits} A device MUST offer VIRTIO_F_VERSION_1. A device MAY fail to operate further -- 2.7.4