Re: [PATCH v1 2/4] vdpa: Allow for printing negotiated features of a device

[Si-Wei Liu <si-wei.liu@oracle.com>]

On 2/10/2022 5:31 AM, Eli Cohen wrote:
> When reading the configuration of a vdpa device, check if the
> VDPA_ATTR_DEV_NEGOTIATED_FEATURES is available. If it is, parse the
> feature bits and print a string representation of each of the feature
> bits.
>
> We keep the strings in two different arrays. One for net device related
> devices and one for generic feature bits.
>
> In this patch we parse only net device specific features. Support for
> other devices can be added later. If the device queried is not a net
> device, we print its bit number only.
>
> Examples:
> 1.
> $ vdpa dev config show vdpa-a
> vdpa-a: mac 00:00:00:00:88:88 link up link_announce false max_vq_pairs 3 \
>          mtu 1500
>    negotiated_features CSUM GUEST_CSUM MTU MAC HOST_TSO4 HOST_TSO6 STATUS \
>                        CTRL_VQ MQ CTRL_MAC_ADDR VERSION_1 ACCESS_PLATFORM
>
> 2. json output
> $ vdpa -j dev config show vdpa-a
> {"config":{"vdpa-a":{"mac":"00:00:00:00:88:88","link":"up","link_announce":false, \
>    "max_vq_pairs":3,"mtu":1500,"negotiated_features":["CSUM","GUEST_CSUM","MTU", \
>    "MAC","HOST_TSO4","HOST_TSO6","STATUS","CTRL_VQ","MQ","CTRL_MAC_ADDR", \
>    "VERSION_1","ACCESS_PLATFORM"]}}}
>
> 3. pretty json
> $ vdpa -jp dev config show vdpa-a
> {
>      "config": {
>          "vdpa-a": {
>              "mac": "00:00:00:00:88:88",
>              "link ": "up",
>              "link_announce ": false,
>              "max_vq_pairs": 3,
>              "mtu": 1500,
>              "negotiated_features": [
> "CSUM","GUEST_CSUM","MTU","MAC","HOST_TSO4","HOST_TSO6","STATUS","CTRL_VQ", \
> "MQ","CTRL_MAC_ADDR","VERSION_1","ACCESS_PLATFORM" ]
>          }
>      }
> }
>
> Signed-off-by: Eli Cohen <elic@nvidia.com>
> ---
>   vdpa/include/uapi/linux/vdpa.h |   2 +
>   vdpa/vdpa.c                    | 126 +++++++++++++++++++++++++++++++--
>   2 files changed, 124 insertions(+), 4 deletions(-)
>
> diff --git a/vdpa/include/uapi/linux/vdpa.h b/vdpa/include/uapi/linux/vdpa.h
> index b7eab069988a..748c350450b2 100644
> --- a/vdpa/include/uapi/linux/vdpa.h
> +++ b/vdpa/include/uapi/linux/vdpa.h
> @@ -40,6 +40,8 @@ enum vdpa_attr {
>   	VDPA_ATTR_DEV_NET_CFG_MAX_VQP,		/* u16 */
>   	VDPA_ATTR_DEV_NET_CFG_MTU,		/* u16 */
>   
> +	VDPA_ATTR_DEV_NEGOTIATED_FEATURES,	/* u64 */
> +
>   	/* new attributes must be added above here */
>   	VDPA_ATTR_MAX,
>   };
> diff --git a/vdpa/vdpa.c b/vdpa/vdpa.c
> index 4ccb564872a0..7deab710913d 100644
> --- a/vdpa/vdpa.c
> +++ b/vdpa/vdpa.c
> @@ -10,6 +10,7 @@
>   #include <linux/virtio_net.h>
>   #include <linux/netlink.h>
>   #include <libmnl/libmnl.h>
> +#include <linux/virtio_ring.h>
>   #include "mnl_utils.h"
>   #include <rt_names.h>
>   
> @@ -78,6 +79,7 @@ static const enum mnl_attr_data_type vdpa_policy[VDPA_ATTR_MAX + 1] = {
>   	[VDPA_ATTR_DEV_VENDOR_ID] = MNL_TYPE_U32,
>   	[VDPA_ATTR_DEV_MAX_VQS] = MNL_TYPE_U32,
>   	[VDPA_ATTR_DEV_MAX_VQ_SIZE] = MNL_TYPE_U16,
> +	[VDPA_ATTR_DEV_NEGOTIATED_FEATURES] = MNL_TYPE_U64,
>   };
>   
>   static int attr_cb(const struct nlattr *attr, void *data)
> @@ -385,17 +387,120 @@ static const char *parse_class(int num)
>   	return class ? class : "< unknown class >";
>   }
>   
> +static const char * const net_feature_strs[64] = {
> +	[VIRTIO_NET_F_CSUM] = "CSUM",
> +	[VIRTIO_NET_F_GUEST_CSUM] = "GUEST_CSUM",
> +	[VIRTIO_NET_F_CTRL_GUEST_OFFLOADS] = "CTRL_GUEST_OFFLOADS",
> +	[VIRTIO_NET_F_MTU] = "MTU",
> +	[VIRTIO_NET_F_MAC] = "MAC",
> +	[VIRTIO_NET_F_GUEST_TSO4] = "GUEST_TSO4",
> +	[VIRTIO_NET_F_GUEST_TSO6] = "GUEST_TSO6",
> +	[VIRTIO_NET_F_GUEST_ECN] = "GUEST_ECN",
> +	[VIRTIO_NET_F_GUEST_UFO] = "GUEST_UFO",
> +	[VIRTIO_NET_F_HOST_TSO4] = "HOST_TSO4",
> +	[VIRTIO_NET_F_HOST_TSO6] = "HOST_TSO6",
> +	[VIRTIO_NET_F_HOST_ECN] = "HOST_ECN",
> +	[VIRTIO_NET_F_HOST_UFO] = "HOST_UFO",
> +	[VIRTIO_NET_F_MRG_RXBUF] = "MRG_RXBUF",
> +	[VIRTIO_NET_F_STATUS] = "STATUS",
> +	[VIRTIO_NET_F_CTRL_VQ] = "CTRL_VQ",
> +	[VIRTIO_NET_F_CTRL_RX] = "CTRL_RX",
> +	[VIRTIO_NET_F_CTRL_VLAN] = "CTRL_VLAN",
> +	[VIRTIO_NET_F_CTRL_RX_EXTRA] = "CTRL_RX_EXTRA",
> +	[VIRTIO_NET_F_GUEST_ANNOUNCE] = "GUEST_ANNOUNCE",
> +	[VIRTIO_NET_F_MQ] = "MQ",
> +	[VIRTIO_F_NOTIFY_ON_EMPTY] = "NOTIFY_ON_EMPTY",
> +	[VIRTIO_NET_F_CTRL_MAC_ADDR] = "CTRL_MAC_ADDR",
> +	[VIRTIO_F_ANY_LAYOUT] = "ANY_LAYOUT",
> +	[VIRTIO_NET_F_RSC_EXT] = "RSC_EXT",
> +	[VIRTIO_NET_F_HASH_REPORT] = "HASH_REPORT",
> +	[VIRTIO_NET_F_RSS] = "RSS",
> +	[VIRTIO_NET_F_STANDBY] = "STANDBY",
> +	[VIRTIO_NET_F_SPEED_DUPLEX] = "SPEED_DUPLEX",
> +};
> +
> +#define VIRTIO_F_IN_ORDER 35
> +#define VIRTIO_F_NOTIFICATION_DATA 38
> +#define VDPA_EXT_FEATURES_SZ (VIRTIO_TRANSPORT_F_END - \
> +			      VIRTIO_TRANSPORT_F_START + 1)
> +
> +static const char * const ext_feature_strs[VDPA_EXT_FEATURES_SZ] = {
> +	[VIRTIO_RING_F_INDIRECT_DESC - VIRTIO_TRANSPORT_F_START] = "RING_INDIRECT_DESC",
> +	[VIRTIO_RING_F_EVENT_IDX - VIRTIO_TRANSPORT_F_START] = "RING_EVENT_IDX",
> +	[VIRTIO_F_VERSION_1 - VIRTIO_TRANSPORT_F_START] = "VERSION_1",
> +	[VIRTIO_F_ACCESS_PLATFORM - VIRTIO_TRANSPORT_F_START] = "ACCESS_PLATFORM",
> +	[VIRTIO_F_RING_PACKED - VIRTIO_TRANSPORT_F_START] = "RING_PACKED",
> +	[VIRTIO_F_IN_ORDER - VIRTIO_TRANSPORT_F_START] = "IN_ORDER",
> +	[VIRTIO_F_ORDER_PLATFORM - VIRTIO_TRANSPORT_F_START] = "ORDER_PLATFORM",
> +	[VIRTIO_F_SR_IOV - VIRTIO_TRANSPORT_F_START] = "SR_IOV",
> +	[VIRTIO_F_NOTIFICATION_DATA - VIRTIO_TRANSPORT_F_START] = "NOTIFICATION_DATA",
> +};
> +
> +static void print_net_features(struct vdpa *vdpa, uint64_t features, bool maxf)
> +{
> +	const char *s;
> +	int i;
> +
> +	if (maxf)
This could use a better name. mgmtdevf maybe?
> +		pr_out_array_start(vdpa, "dev_features");
> +	else
> +		pr_out_array_start(vdpa, "negotiated_features");
> +
> +	for (i = 0; i < 64; i++) {
> +		if (!(features & (1ULL << i)))
> +			continue;
> +
> +		if (i >= VIRTIO_TRANSPORT_F_START && i <= VIRTIO_TRANSPORT_F_END)
> +			s = ext_feature_strs[i - VIRTIO_TRANSPORT_F_START];
> +		else
> +			s = net_feature_strs[i];
> +
> +		if (!s)
> +			print_uint(PRINT_ANY, NULL, " unrecognized_bit_%d", i);
> +		else
> +			print_string(PRINT_ANY, NULL, " %s", s);
> +	}
> +	pr_out_array_end(vdpa);
> +}
> +
> +static void print_generic_features(struct vdpa *vdpa, uint64_t features, bool maxf)
> +{
> +	const char *s;
> +	int i;
> +
> +	if (maxf)
> +		pr_out_array_start(vdpa, "dev_features");
> +	else
> +		pr_out_array_start(vdpa, "negotiated_features");
> +
> +	for (i = 0; i < 64; i++) {
> +		if (!(features & (1ULL << i)))
> +			continue;
> +
> +		if (i >= VIRTIO_TRANSPORT_F_START && i <= VIRTIO_TRANSPORT_F_END)
> +			s = ext_feature_strs[i - VIRTIO_TRANSPORT_F_START];
> +		else
> +			s = NULL;
> +
> +		if (!s)
> +			print_uint(PRINT_ANY, NULL, " bit_%d", i);
> +		else
> +			print_string(PRINT_ANY, NULL, " %s", s);
> +	}
> +	pr_out_array_end(vdpa);
> +}
> +
It looks like most of the implantation in the above two functions are 
the same and the rest are similar. I wonder if can consolidate into one 
by adding a virtio type (dev_id) argument? You may create another global 
static array that helps mapping VIRTIO_ID_NET to net_feature_strs?

>   static void pr_out_mgmtdev_show(struct vdpa *vdpa, const struct nlmsghdr *nlh,
>   				struct nlattr **tb)
>   {
> +	uint64_t classes = 0;
>   	const char *class;
>   	unsigned int i;
>   
>   	pr_out_handle_start(vdpa, tb);
>   
>   	if (tb[VDPA_ATTR_MGMTDEV_SUPPORTED_CLASSES]) {
> -		uint64_t classes = mnl_attr_get_u64(tb[VDPA_ATTR_MGMTDEV_SUPPORTED_CLASSES]);
> -
> +		classes = mnl_attr_get_u64(tb[VDPA_ATTR_MGMTDEV_SUPPORTED_CLASSES]);
>   		pr_out_array_start(vdpa, "supported_classes");
This looks like a minor adjustment to the existing code? Not sure if 
worth another patch though.

>   
>   		for (i = 1; i < 64; i++) {
> @@ -579,9 +684,10 @@ static int cmd_dev_del(struct vdpa *vdpa,  int argc, char **argv)
>   	return mnlu_gen_socket_sndrcv(&vdpa->nlg, nlh, NULL, NULL);
>   }
>   
> -static void pr_out_dev_net_config(struct nlattr **tb)
> +static void pr_out_dev_net_config(struct vdpa *vdpa, struct nlattr **tb)
>   {
>   	SPRINT_BUF(macaddr);
> +	uint64_t val_u64;
>   	uint16_t val_u16;
>   
>   	if (tb[VDPA_ATTR_DEV_NET_CFG_MACADDR]) {
> @@ -610,6 +716,18 @@ static void pr_out_dev_net_config(struct nlattr **tb)
>   		val_u16 = mnl_attr_get_u16(tb[VDPA_ATTR_DEV_NET_CFG_MTU]);
>   		print_uint(PRINT_ANY, "mtu", "mtu %d ", val_u16);
>   	}
> +	if (tb[VDPA_ATTR_DEV_NEGOTIATED_FEATURES]) {
> +		uint16_t dev_id = 0;
> +
> +		if (tb[VDPA_ATTR_DEV_ID])
> +			dev_id = mnl_attr_get_u32(tb[VDPA_ATTR_DEV_ID]);
> +
> +		val_u64 = mnl_attr_get_u64(tb[VDPA_ATTR_DEV_NEGOTIATED_FEATURES]);
> +		if (tb[VDPA_ATTR_DEV_NEGOTIATED_FEATURES] && dev_id == VIRTIO_ID_NET)
> +			print_net_features(vdpa, val_u64, false);
> +		else
> +			print_generic_features(vdpa, val_u64, true);
Why the last arg is true? That would output the dev_features line instead.

-Siwei

> +	}
>   }
>   
>   static void pr_out_dev_config(struct vdpa *vdpa, struct nlattr **tb)
> @@ -619,7 +737,7 @@ static void pr_out_dev_config(struct vdpa *vdpa, struct nlattr **tb)
>   	pr_out_vdev_handle_start(vdpa, tb);
>   	switch (device_id) {
>   	case VIRTIO_ID_NET:
> -		pr_out_dev_net_config(tb);
> +		pr_out_dev_net_config(vdpa, tb);
>   		break;
>   	default:
>   		break;