2020-02-29 17:14:31

by Yuri Benditovich

[permalink] [raw]
Subject: [PATCH 2/3] virtio-net: Introduce RSS receive steering feature

RSS (Receive-side scaling) defines hash calculation
rules and decision on receive virtqueue according to
the calculated hash, provided mask to apply and
provided indirection table containing indices of
receive virqueues. The driver sends the control
command to enable multiqueue and provide parameters
for receive steering.

Signed-off-by: Yuri Benditovich <[email protected]>
---
include/uapi/linux/virtio_net.h | 42 +++++++++++++++++++++++++++++++--
1 file changed, 40 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
index 6e26a2cc6ad0..7a342657fb6c 100644
--- a/include/uapi/linux/virtio_net.h
+++ b/include/uapi/linux/virtio_net.h
@@ -57,6 +57,7 @@
* Steering */
#define VIRTIO_NET_F_CTRL_MAC_ADDR 23 /* Set MAC address */

+#define VIRTIO_NET_F_RSS 60 /* Supports RSS RX steering */
#define VIRTIO_NET_F_RSC_EXT 61 /* extended coalescing info */
#define VIRTIO_NET_F_STANDBY 62 /* Act as standby for another device
* with the same MAC.
@@ -70,6 +71,17 @@
#define VIRTIO_NET_S_LINK_UP 1 /* Link is up */
#define VIRTIO_NET_S_ANNOUNCE 2 /* Announcement is needed */

+/* supported/enabled hash types */
+#define VIRTIO_NET_RSS_HASH_TYPE_IPv4 (1 << 0)
+#define VIRTIO_NET_RSS_HASH_TYPE_TCPv4 (1 << 1)
+#define VIRTIO_NET_RSS_HASH_TYPE_UDPv4 (1 << 2)
+#define VIRTIO_NET_RSS_HASH_TYPE_IPv6 (1 << 3)
+#define VIRTIO_NET_RSS_HASH_TYPE_TCPv6 (1 << 4)
+#define VIRTIO_NET_RSS_HASH_TYPE_UDPv6 (1 << 5)
+#define VIRTIO_NET_RSS_HASH_TYPE_IP_EX (1 << 6)
+#define VIRTIO_NET_RSS_HASH_TYPE_TCP_EX (1 << 7)
+#define VIRTIO_NET_RSS_HASH_TYPE_UDP_EX (1 << 8)
+
struct virtio_net_config {
/* The config defining mac address (if VIRTIO_NET_F_MAC) */
__u8 mac[ETH_ALEN];
@@ -93,6 +105,12 @@ struct virtio_net_config {
* Any other value stands for unknown.
*/
__u8 duplex;
+ /* maximal size of RSS key */
+ __u8 rss_max_key_size;
+ /* maximal number of indirection table entries */
+ __u16 rss_max_indirection_table_length;
+ /* bitmask of supported VIRTIO_NET_RSS_HASH_ types */
+ __u32 supported_hash_types;
} __attribute__((packed));

/*
@@ -236,7 +254,9 @@ struct virtio_net_ctrl_mac {

/*
* Control Receive Flow Steering
- *
+ */
+#define VIRTIO_NET_CTRL_MQ 4
+/*
* The command VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET
* enables Receive Flow Steering, specifying the number of the transmit and
* receive queues that will be used. After the command is consumed and acked by
@@ -249,11 +269,29 @@ struct virtio_net_ctrl_mq {
__virtio16 virtqueue_pairs;
};

-#define VIRTIO_NET_CTRL_MQ 4
#define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET 0
#define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN 1
#define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX 0x8000

+/*
+ * The command VIRTIO_NET_CTRL_MQ_RSS_CONFIG has the same effect as
+ * VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET does and additionally configures
+ * the receive steering to use a hash calculated for incoming packet
+ * to decide on receive virtqueue to place the packet. The command
+ * also provides parameters to calculate a hash and receive virtqueue.
+ */
+struct virtio_net_rss_config {
+ __virtio32 hash_types;
+ __virtio16 indirection_table_mask;
+ __virtio16 unclassified_queue;
+ __virtio16 indirection_table[1/* + indirection_table_mask*/];
+ __virtio16 max_tx_vq;
+ __u8 hash_key_length;
+ __u8 hash_key_data[/*hash_key_length*/];
+};
+
+ #define VIRTIO_NET_CTRL_MQ_RSS_CONFIG 1
+
/*
* Control network offloads
*
--
2.17.1


2020-03-01 08:50:17

by Michael S. Tsirkin

[permalink] [raw]
Subject: Re: [PATCH 2/3] virtio-net: Introduce RSS receive steering feature

On Sat, Feb 29, 2020 at 07:13:00PM +0200, Yuri Benditovich wrote:
> RSS (Receive-side scaling) defines hash calculation
> rules and decision on receive virtqueue according to
> the calculated hash, provided mask to apply and
> provided indirection table containing indices of
> receive virqueues. The driver sends the control
> command to enable multiqueue and provide parameters
> for receive steering.
>
> Signed-off-by: Yuri Benditovich <[email protected]>
> ---
> include/uapi/linux/virtio_net.h | 42 +++++++++++++++++++++++++++++++--
> 1 file changed, 40 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
> index 6e26a2cc6ad0..7a342657fb6c 100644
> --- a/include/uapi/linux/virtio_net.h
> +++ b/include/uapi/linux/virtio_net.h
> @@ -57,6 +57,7 @@
> * Steering */
> #define VIRTIO_NET_F_CTRL_MAC_ADDR 23 /* Set MAC address */
>
> +#define VIRTIO_NET_F_RSS 60 /* Supports RSS RX steering */
> #define VIRTIO_NET_F_RSC_EXT 61 /* extended coalescing info */
> #define VIRTIO_NET_F_STANDBY 62 /* Act as standby for another device
> * with the same MAC.
> @@ -70,6 +71,17 @@
> #define VIRTIO_NET_S_LINK_UP 1 /* Link is up */
> #define VIRTIO_NET_S_ANNOUNCE 2 /* Announcement is needed */
>
> +/* supported/enabled hash types */
> +#define VIRTIO_NET_RSS_HASH_TYPE_IPv4 (1 << 0)
> +#define VIRTIO_NET_RSS_HASH_TYPE_TCPv4 (1 << 1)
> +#define VIRTIO_NET_RSS_HASH_TYPE_UDPv4 (1 << 2)
> +#define VIRTIO_NET_RSS_HASH_TYPE_IPv6 (1 << 3)
> +#define VIRTIO_NET_RSS_HASH_TYPE_TCPv6 (1 << 4)
> +#define VIRTIO_NET_RSS_HASH_TYPE_UDPv6 (1 << 5)
> +#define VIRTIO_NET_RSS_HASH_TYPE_IP_EX (1 << 6)
> +#define VIRTIO_NET_RSS_HASH_TYPE_TCP_EX (1 << 7)
> +#define VIRTIO_NET_RSS_HASH_TYPE_UDP_EX (1 << 8)
> +
> struct virtio_net_config {
> /* The config defining mac address (if VIRTIO_NET_F_MAC) */
> __u8 mac[ETH_ALEN];
> @@ -93,6 +105,12 @@ struct virtio_net_config {
> * Any other value stands for unknown.
> */
> __u8 duplex;
> + /* maximal size of RSS key */
> + __u8 rss_max_key_size;
> + /* maximal number of indirection table entries */
> + __u16 rss_max_indirection_table_length;

This mirrors spec language. However I just stumbled upon this:

https://en.wikipedia.org/wiki/Maximal_and_minimal_elements

which seems to say maximal means "local maximum".
So I think we should fix both the spec and this header to
say "maximum" instead of "maximal".

Thanks!



> + /* bitmask of supported VIRTIO_NET_RSS_HASH_ types */
> + __u32 supported_hash_types;
> } __attribute__((packed));
>
> /*
> @@ -236,7 +254,9 @@ struct virtio_net_ctrl_mac {
>
> /*
> * Control Receive Flow Steering
> - *
> + */
> +#define VIRTIO_NET_CTRL_MQ 4
> +/*
> * The command VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET
> * enables Receive Flow Steering, specifying the number of the transmit and
> * receive queues that will be used. After the command is consumed and acked by
> @@ -249,11 +269,29 @@ struct virtio_net_ctrl_mq {
> __virtio16 virtqueue_pairs;
> };
>
> -#define VIRTIO_NET_CTRL_MQ 4
> #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET 0
> #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN 1
> #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX 0x8000
>
> +/*
> + * The command VIRTIO_NET_CTRL_MQ_RSS_CONFIG has the same effect as
> + * VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET does and additionally configures
> + * the receive steering to use a hash calculated for incoming packet
> + * to decide on receive virtqueue to place the packet. The command
> + * also provides parameters to calculate a hash and receive virtqueue.
> + */
> +struct virtio_net_rss_config {
> + __virtio32 hash_types;
> + __virtio16 indirection_table_mask;
> + __virtio16 unclassified_queue;
> + __virtio16 indirection_table[1/* + indirection_table_mask*/];
> + __virtio16 max_tx_vq;
> + __u8 hash_key_length;
> + __u8 hash_key_data[/*hash_key_length*/];
> +};


Should use __le and not __virtio.
__virtio is for legacy types which sometimes have variable endian-ness.


> +
> + #define VIRTIO_NET_CTRL_MQ_RSS_CONFIG 1
> +
> /*
> * Control network offloads
> *
> --
> 2.17.1