gve: Add header split data path

Add header buffers and ethtool support to enable header split via the
tcp-data-split flag in ethtool's ringparam config. A coherent dma memory
is allocated for the header buffers. There is one header buffer per ring
entry by calculating the offset to the header-buffers starting address.
The header buffer is always copied directly into the skb and payload is
always added as frags. When there is a header buffer overflow or the
header length is 0, the driver places the whole unsplit packet in frags.

When toggling header split, the driver will call gve_adjust_config to
set its queues appropriately. If header split is enabled by the user and
the max packet buffer size is no less than 4KB, driver will set the
packet buffer size as 4KB to support TCP_ZEROCOPY_RECEIVE. Otherwise the
driver will use the default 2KB as the packet buffer size.

`ethtool -G <dev> tcp-data-split on/off` is the command to toggle header
split.
`ethtool -g <dev>` will show the status of header split with the field
of `tcp-data-split`.

Co-developed-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Add header split device option

To enable header split via ethtool, we first need to query the device to
get the max rx buffer size and header buffer size. Add a device option
to get these values and store them in the driver. If the header buffer
size received from the device is non-zero, it means header split is
supported in the device.

Currently the max rx buffer size will only be used when header split is
enabled which will set the data_buffer_size_dqo to be the max rx buffer
size. Also change the data_buffer_size_dqo from int to u16 since we are
modifying it and making it to be consistent with max_rx_buffer_size.

Co-developed-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Reviewed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Add page size register to the register_page_list command.

This register is required on platforms with page sizes greater than 4k.
This is because the tx side of the driver vmaps the entire queue page
list of pages into a single flat address space, then uses the entire
space. Without communicating the guest page size to the backend, the
backend will only access the first 4k of each page in the queue page list.

Signed-off-by: Jordan Kimbrough <jrkim@google.com>
Signed-off-by: John Fraker <jfraker@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20231128002648.320892-5-jfraker@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

gve: Remove obsolete checks that rely on page size.

These checks are safe to remove as they are no longer enforced by the
backend. Retaining them would require updating them to work differently
with page sizes larger than 4k.

Signed-off-by: Jordan Kimbrough <jrkim@google.com>
Signed-off-by: John Fraker <jfraker@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20231128002648.320892-4-jfraker@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

gve: Deprecate adminq_pfn for pci revision 0x1.

adminq_pfn assumes a page size of 4k, causing this mechanism to break in
kernels compiled with different page sizes. A new PCI device revision was
needed for the device to be able to communicate with the driver how to
set up the admin queue prior to having access to the admin queue.

Signed-off-by: Jordan Kimbrough <jrkim@google.com>
Signed-off-by: John Fraker <jfraker@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20231128002648.320892-3-jfraker@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

gve: Perform adminq allocations through a dma_pool.

This allows the adminq to be smaller than a page, paving the way for
non 4k page support. This is to support platforms where PAGE_SIZE
is not 4k, such as some ARM platforms.

Signed-off-by: Jordan Kimbrough <jrkim@google.com>
Signed-off-by: John Fraker <jfraker@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20231128002648.320892-2-jfraker@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

gve: Control path for DQO-QPL

GVE supports QPL ("queue-page-list") mode where
all data is communicated through a set of pre-registered
pages. Adding this mode to DQO descriptor format.

Add checks, abi-changes and device options to support
QPL mode for DQO in addition to GQI. Also, use
pages-per-qpl supplied by device-option to control the
size of the "queue-page-list".

Signed-off-by: Rushil Gupta <rushilg@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Praveen Kaligineedi <pkaligineedi@google.com>
Signed-off-by: Bailey Forrest <bcf@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Changes to add new TX queues

Changes to enable adding and removing TX queues without calling
gve_close() and gve_open().

Made the following changes:
1) priv->tx, priv->rx and priv->qpls arrays are allocated based on
max tx queues and max rx queues
2) Changed gve_adminq_create_tx_queues(), gve_adminq_destroy_tx_queues(),
gve_tx_alloc_rings() and gve_tx_free_rings() functions to add/remove a
subset of TX queues rather than all the TX queues.

Signed-off-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Jeroen de Borst <jeroendb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Adding a new AdminQ command to verify driver

Check whether the driver is compatible with the device
presented.

Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: fix the wrong AdminQ buffer queue index check

The 'tail' and 'head' are 'unsigned int' type free-running count, when
'head' is overflow, the 'int i (= tail) < u32 head' will be false:

Only '- loop 0: idx = 63' result is shown, so it needs to use 'int' type
to compare, it can handle the overflow correctly.

typedef uint32_t u32;

int main()
{
u32 tail, head;
int stail, shead;
int i, loop;

tail = 0xffffffff;
head = 0x00000000;

for (i = tail, loop = 0; i < head; i++) {
unsigned int idx = i & 63;

printf("+ loop %d: idx = %u\n", loop++, idx);
}

stail = tail;
shead = head;
for (i = stail, loop = 0; i < shead; i++) {
unsigned int idx = i & 63;

printf("- loop %d: idx = %u\n", loop++, idx);
}

return 0;
}

Fixes: 5cdad90de62c ("gve: Batch AQ commands for creating and destroying queues.")
Signed-off-by: Haiyue Wang <haiyue.wang@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Move the irq db indexes out of the ntfy block struct

Giving the device access to other kernel structs is not ideal.
Move the indexes into their own array and just keep pointers to
them in the ntfy block struct.

Signed-off-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David Awogbemila <awogbemila@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Correct order of processing device options

The legacy raw addressing device option was processed before the
new RDA queue format option. This caused the supported features mask,
which is provided only on the RDA queue format option, not to be set.

This disabled jumbo-frame support when using raw adressing.

Fixes: 255489f5b33c ("gve: Add a jumbo-frame device option")
Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Correct order of processing device options

The legacy raw addressing device option was processed before the
new RDA queue format option. This caused the supported features mask,
which is provided only on the RDA queue format option, not to be set.

This disabled jumbo-frame support when using raw adressing.

Fixes: 255489f5b33c ("gve: Add a jumbo-frame device option")
Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Link: https://lore.kernel.org/r/20211220192746.2900594-1-jeroendb@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

gve: Add a jumbo-frame device option.

A widely deployed driver has a bug that will cause the driver not
to load when a max_mtu > 2048 is present in the device descriptor.

To avoid this bug while still enabling jumbo frames, we present a lower
max_mtu in the device descriptor and pass the actual max_mtu in
a separate device option.

The driver supports 2 different queue formats. To enable features
on one queue format, but not the other, a supported_features mask
was added to the device options in the device descriptor.

Signed-off-by: Shailend Chand <shailend@google.com>
Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Implement packet continuation for RX.

This enables the driver to receive RX packets spread across multiple
buffers:

For a given multi-fragment packet the "packet continuation" bit is set
on all descriptors except the last one. These descriptors' payloads are
combined into a single SKB before the SKB is handed to the
networking stack.

This change adds a "packet buffer size" notion for RX queues. The
CreateRxQueue AdminQueue command sent to the device now includes the
packet_buffer_size.

We opt for a packet_buffer_size of PAGE_SIZE / 2 to give the
driver the opportunity to flip pages where we can instead of copying.

Signed-off-by: David Awogbemila <awogbemila@google.com>
Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ethernet: use eth_hw_addr_set() instead of ether_addr_copy()

Convert Ethernet from ether_addr_copy() to eth_hw_addr_set():

@@
expression dev, np;
@@
- ether_addr_copy(dev->dev_addr, np)
+ eth_hw_addr_set(dev, np)

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: fix the wrong AdminQ buffer overflow check

The 'tail' pointer is also free-running count, so it needs to be masked
as 'adminq_prod_cnt' does, to become an index value of AdminQ buffer.

Fixes: 5cdad90de62c ("gve: Batch AQ commands for creating and destroying queues.")
Signed-off-by: Haiyue Wang <haiyue.wang@intel.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: DQO: Add core netdev features

Add napi netdev device registration, interrupt handling and initial tx
and rx polling stubs. The stubs will be filled in follow-on patches.

Also:
- LRO feature advertisement and handling
- Also update ethtool logic

Signed-off-by: Bailey Forrest <bcf@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Update adminq commands to support DQO queues

DQO queue creation requires additional parameters:
- TX completion/RX buffer queue size
- TX completion/RX buffer queue address
- TX/RX queue size
- RX buffer size

Signed-off-by: Bailey Forrest <bcf@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Add support for DQO RX PTYPE map

Unlike GQI, DQO RX descriptors do not contain the L3 and L4 type of the
packet. L3 and L4 types are necessary in order to set the hash and csum
on RX SKBs correctly.

DQO RX descriptors instead contain a 10 bit PTYPE index. The PTYPE map
enables the device to tell the driver how to map from PTYPE index to
L3/L4 type.

The device doesn't provide any guarantees about the range of possible
PTYPEs, so we just use a 1024 entry array to implement a fast mapping
structure.

Signed-off-by: Bailey Forrest <bcf@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: adminq: DQO specific device descriptor logic

- In addition to TX and RX queues, DQO has TX completion and RX buffer
queues.
- TX completions are received when the device has completed sending a
packet on the wire.
- RX buffers are posted on a separate queue form the RX completions.
- DQO descriptor rings are allowed to be smaller than PAGE_SIZE.

Signed-off-by: Bailey Forrest <bcf@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Introduce per netdev `enum gve_queue_format`

The currently supported queue formats are:
- GQI_RDA - GQI with raw DMA addressing
- GQI_QPL - GQI with queue page list
- DQO_RDA - DQO with raw DMA addressing

The old `gve_priv.raw_addressing` value is only used for GQI_RDA, so we
remove it in favor of just checking against GQI_RDA

Signed-off-by: Bailey Forrest <bcf@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Introduce a new model for device options

The current model uses an integer ID and a fixed size struct for the
parameters of each device option.

The new model allows the device option structs to grow in size over
time. A driver may assume that changes to device option structs will
always be appended.

New device options will also generally have a
`supported_features_mask` so that the driver knows which fields within a
particular device option are enabled.

`gve_device_option.feat_mask` is changed to `required_features_mask`,
and it is a bitmask which must match the value expected by the driver.
This gives the device the ability to break backwards compatibility with
old drivers for certain features by blocking the old drivers from trying
to use the feature.

We maintain ABI compatibility with the old model for
GVE_DEV_OPT_ID_RAW_ADDRESSING in case a driver is using a device which
does not support the new model.

This patch introduces some new terminology:

RDA - Raw DMA Addressing - Buffers associated with SKBs are directly DMA
mapped and read/updated by the device.

QPL - Queue Page Lists - Driver uses bounce buffers which are DMA mapped
with the device for read/write and data is copied from/to SKBs.

Signed-off-by: Bailey Forrest <bcf@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Add support for raw addressing in the tx path

During TX, skbs' data addresses are dma_map'ed and passed to the NIC.
This means that the device can perform DMA directly from these addresses
and the driver does not have to copy the buffer content into
pre-allocated buffers/qpls (as in qpl mode).

Reviewed-by: Yangchun Fu <yangchun@google.com>
Signed-off-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David Awogbemila <awogbemila@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Add support for raw addressing to the rx path

Add support to use raw dma addresses in the rx path. Due to this new
support we can alloc a new buffer instead of making a copy.

RX buffers are handed to the networking stack and are
re-allocated as needed, avoiding the need to use
skb_copy_to_linear_data() as in "qpl" mode.

Reviewed-by: Yangchun Fu <yangchun@google.com>
Signed-off-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David Awogbemila <awogbemila@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Add support for raw addressing device option

Add support to describe device for parsing device options. As
the first device option, add raw addressing.

"Raw Addressing" mode (as opposed to the current "qpl" mode) is an
operational mode which allows the driver avoid bounce buffer copies
which it currently performs using pre-allocated qpls (queue_page_lists)
when sending and receiving packets.
For egress packets, the provided skb data addresses will be dma_map'ed and
passed to the device, allowing the NIC can perform DMA directly - the
driver will not have to copy the buffer content into pre-allocated
buffers/qpls (as in qpl mode).
For ingress packets, copies are also eliminated as buffers are handed to
the networking stack and then recycled or re-allocated as
necessary, avoiding the use of skb_copy_to_linear_data().

This patch only introduces the option to the driver.
Subsequent patches will add the ingress and egress functionality.

Reviewed-by: Yangchun Fu <yangchun@google.com>
Signed-off-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David Awogbemila <awogbemila@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Enable Link Speed Reporting in the driver.

This change allows the driver to report the device link speed
when the ethtool command:
ethtool <nic name>
is run.
Getting the link speed is done via a new admin queue command:
ReportLinkSpeed.

Reviewed-by: Yangchun Fu <yangchun@google.com>
Signed-off-by: David Awogbemila <awogbemila@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Batch AQ commands for creating and destroying queues.

Adds support for batching AQ commands and uses it for creating and
destroying queues.

Reviewed-by: Yangchun Fu <yangchun@google.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
Signed-off-by: David Awogbemila <awogbemila@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Add Gvnic stats AQ command and ethtool show/set-priv-flags.

This adds functionality to report driver stats to Hypervisor.
(Users may want to turn this feature off as a matter of privacy
so a "report-stats" flag is added as an ethtool priv option.
It is also disabled by default.)
The hypervisor would trigger a stats report in case "too many"
packets dropped; the stats would be useful in debugging stuck
queues.
A "stats_report_trigger_cnt" stat is added to count the number of times
the hypervisor attempts to trigger stats report.

A timer is also added so that when report-stats is enabled, stat are
updated once every 20 seconds.

Reviewed-by: Yangchun Fu <yangchun@google.com>
Signed-off-by: Kuo Zhao <kuozhao@google.com>
Signed-off-by: David Awogbemila <awogbemila@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Use dev_info/err instead of netif_info/err.

Update the driver to use dev_info/err instead of netif_info/err.

Reviewed-by: Yangchun Fu <yangchun@google.com>
Signed-off-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David Awogbemila <awogbemila@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Add stats for gve.

Sample output of "ethtool -S <interface-name>" with 1 RX queue and 1 TX
queue:
NIC statistics:
rx_packets: 1039
tx_packets: 37
rx_bytes: 822071
tx_bytes: 4100
rx_dropped: 0
tx_dropped: 0
tx_timeouts: 0
rx_skb_alloc_fail: 0
rx_buf_alloc_fail: 0
rx_desc_err_dropped_pkt: 0
interface_up_cnt: 1
interface_down_cnt: 0
reset_cnt: 0
page_alloc_fail: 0
dma_mapping_error: 0
rx_posted_desc[0]: 1365
rx_completed_desc[0]: 341
rx_bytes[0]: 215094
rx_dropped_pkt[0]: 0
rx_copybreak_pkt[0]: 3
rx_copied_pkt[0]: 3
tx_posted_desc[0]: 6
tx_completed_desc[0]: 6
tx_bytes[0]: 420
tx_wake[0]: 0
tx_stop[0]: 0
tx_event_counter[0]: 6
adminq_prod_cnt: 34
adminq_cmd_fail: 0
adminq_timeouts: 0
adminq_describe_device_cnt: 1
adminq_cfg_device_resources_cnt: 1
adminq_register_page_list_cnt: 16
adminq_unregister_page_list_cnt: 0
adminq_create_tx_queue_cnt: 8
adminq_create_rx_queue_cnt: 8
adminq_destroy_tx_queue_cnt: 0
adminq_destroy_rx_queue_cnt: 0
adminq_dcfg_device_resources_cnt: 0
adminq_set_driver_parameter_cnt: 0

Reviewed-by: Yangchun Fu <yangchun@google.com>
Signed-off-by: Kuo Zhao <kuozhao@google.com>
Signed-off-by: David Awogbemila <awogbemila@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Add transmit and receive support

Add support for passing traffic.

Signed-off-by: Catherine Sullivan <csully@google.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
Signed-off-by: Jon Olson <jonolson@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Luigi Rizzo <lrizzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

gve: Add basic driver framework for Compute Engine Virtual NIC

Add a driver framework for the Compute Engine Virtual NIC that will be
available in the future.

At this point the only functionality is loading the driver.

Signed-off-by: Catherine Sullivan <csully@google.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
Signed-off-by: Jon Olson <jonolson@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Luigi Rizzo <lrizzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>