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diff --git a/content.tex b/content.tex index 356a1d5..3b39602 100644 --- a/content.tex +++ b/content.tex @@ -2343,6 +2343,8 @@ features. \item[VIRTIO_NET_F_MQ(22)] Device supports multiqueue with automatic receive steering. +\item[VIRTIO_NET_F_CTRL_MAC_ADDR(23)] Set MAC address through control + channel. \end{description} \subsubsection{Legacy Interface: Feature bits}\label{sec:Device Types / Network Device / Feature bits / Legacy Interface: Feature bits} @@ -2681,6 +2683,7 @@ off. The command-specific-data is one byte containing 0 (off) or #define VIRTIO_NET_CTRL_MAC 1 #define VIRTIO_NET_CTRL_MAC_TABLE_SET 0 + #define VIRTIO_NET_CTRL_MAC_ADDR_SET 1 \end{lstlisting} The device can filter incoming packets by any number of destination @@ -2693,10 +2696,40 @@ command-specific-data is two variable length tables of 6-byte MAC addresses. The first table contains unicast addresses, and the second contains multicast addresses. +When VIRTIO_NET_F_MAC_ADDR is not negotiated, the mac field in +config space is writeable and is used to set the default MAC +address which rx filtering accepts. +When VIRTIO_NET_F_MAC_ADDR is negotiated, the mac field in +config space becomes read-only. +The VIRTIO_NET_CTRL_MAC_ADDR_SET command is used to set the +default MAC address which rx filtering +accepts + +Depending on whether VIRTIO_NET_F_MAC_ADDR has been negotiated, +the mac field in config space or the VIRTIO_NET_CTRL_MAC_ADDR_SET +is used to set the default MAC address which rx filtering +accepts. +The command-specific-data for VIRTIO_NET_CTRL_MAC_ADDR_SET is +the 6-byte MAC address. + +The +VIRTIO_NET_CTRL_MAC_ADDR_SET command is atomic whereas the +mac field in config space is not, therefore drivers +MUST negotiate VIRTIO_NET_F_MAC_ADDR if they change +mac address when device is accepting incoming packets. + \subparagraph{Legacy Interface: Setting MAC Address Filtering}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Setting MAC Address Filtering / Legacy Interface: Setting MAC Address Filtering} For legacy devices, the entries field in struct virtio_net_ctrl_mac is the native endian of the guest rather than (necessarily) little-endian. +Legacy drivers that didn't negotiate VIRTIO_NET_F_MAC_ADDR +changed the mac field in config space when NIC is accepting +incoming packets. These drivers always wrote the mac value from +first to last byte, therefore after detecting such drivers, +a transitional device CAN defer MAC update, or CAN defer +processing incoming packets until driver writes the last byte +of the mac field in config space. + \paragraph{VLAN Filtering}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / VLAN Filtering} If the driver negotiates the VIRTION_NET_F_CTRL_VLAN feature, it |