ethernet/google/gve.rst

1 .. SPDX-License-Identifier: GPL-2.0+
12 +--------------+----------+---------+
16 +--------------+----------+---------+
18 +--------------+----------+---------+
19 |Sub-vendor ID | `0x1AE0` | Google  |
20 +--------------+----------+---------+
21 |Sub-device ID | `0x0058` |         |
22 +--------------+----------+---------+
24 +--------------+----------+---------+
26 +--------------+----------+---------+
30 The gVNIC PCI device exposes three 32-bit memory BARS:
31 - Bar0 - Device configuration and status registers.
32 - Bar1 - MSI-X vector table
33 - Bar2 - IRQ, RX and TX doorbells
38  - Registers
39     - A block of MMIO registers
40     - See gve_register.h for more detail
41  - Admin Queue
42     - See description below
43  - Reset
44     - At any time the device can be reset
45  - Interrupts
46     - See supported interrupts below
47  - Transmit and Receive Queues
48     - See description below
51 ------------------
56 ------------------
58 QPL ("queue-page-list") mode communicates data through a set of
59 pre-registered pages.
61 For RDA ("raw DMA addressing") mode, the set of pages is dynamic.
65 ---------
72 ----------
73 - Admin Queue messages and registers are all Big Endian.
74 - GQI descriptors and datapath registers are Big Endian.
75 - DQO descriptors and datapath registers are Little Endian.
78 ----------------
95 -------------
101 ----------
109 The handler for the management irq simply queues the service task in
115 the queues associated with that interrupt.
118 and poll the queues.
120 GQI Traffic Queues
121 ------------------
122 GQI queues are composed of a descriptor ring and a buffer and are assigned to a
125 The descriptor rings are power-of-two-sized ring buffers consisting of
126 fixed-size descriptors. They advance their head pointer using a __be32
128 descriptors in-order and updating a __be32 counter. Both the doorbell
145 DQO Traffic Queues
146 ------------------
147 - Every TX and RX queue is assigned a notification block.
149 - TX and RX buffers queues, which send descriptors to the device, use MMIO
152 - RX and TX completion queues, which receive descriptors from the device, use a
159 - It's the driver's responsibility to ensure that the RX and TX completion
160   queues are not overrun. This can be accomplished by limiting the number of
163 - TX packets have a 16 bit completion_tag and RX buffers have a 16 bit
164   buffer_id. These will be returned on the TX completion and RX queues
169 A packet's buffers are DMA mapped for the device to access before transmission.