[dpdk-stable] [PATCH] net/virtio-user: check negotiated features before set

[eric zhang]

From: Eric Zhang <eric.zhang at windriver.com>

[ backported from upstream commit 1db4d2330bc849a19b9f18479ae7a5a75bc01df2 ]

This patch checks negotiated features to see if necessary to offload
before set the tap device offload capabilities. It also checks if kernel
support the TUNSETOFFLOAD operation.

Fixes: 5e97e4202563 ("net/virtio-user: enable offloading")
Cc: stable at dpdk.org

Signed-off-by: Eric Zhang <eric.zhang at windriver.com>
Reviewed-by: Tiwei Bie <tiwei.bie at intel.com>
---
 drivers/net/virtio/virtio_user/vhost_kernel.c     | 19 ++++---
 drivers/net/virtio/virtio_user/vhost_kernel_tap.c | 68 ++++++++++++++++++-----
 drivers/net/virtio/virtio_user/vhost_kernel_tap.h |  3 +-
 3 files changed, 68 insertions(+), 22 deletions(-)

diff --git a/drivers/net/virtio/virtio_user/vhost_kernel.c b/drivers/net/virtio/virtio_user/vhost_kernel.c
index 68d28b1..3502001 100644
--- a/drivers/net/virtio/virtio_user/vhost_kernel.c
+++ b/drivers/net/virtio/virtio_user/vhost_kernel.c
@@ -189,8 +189,8 @@ prepare_vhost_memory_kernel(void)
 	 (1ULL << VIRTIO_NET_F_HOST_TSO6) |	\
 	 (1ULL << VIRTIO_NET_F_CSUM))
 
-static int
-tap_supporte_mq(void)
+static unsigned int
+tap_support_features(void)
 {
 	int tapfd;
 	unsigned int tap_features;
@@ -209,7 +209,7 @@ tap_supporte_mq(void)
 	}
 
 	close(tapfd);
-	return tap_features & IFF_MULTI_QUEUE;
+	return tap_features;
 }
 
 static int
@@ -223,6 +223,7 @@ vhost_kernel_ioctl(struct virtio_user_dev *dev,
 	struct vhost_memory_kernel *vm = NULL;
 	int vhostfd;
 	unsigned int queue_sel;
+	unsigned int features;
 
 	PMD_DRV_LOG(INFO, "%s", vhost_msg_strings[req]);
 
@@ -276,17 +277,20 @@ vhost_kernel_ioctl(struct virtio_user_dev *dev,
 	}
 
 	if (!ret && req_kernel == VHOST_GET_FEATURES) {
+		features = tap_support_features();
 		/* with tap as the backend, all these features are supported
 		 * but not claimed by vhost-net, so we add them back when
 		 * reporting to upper layer.
 		 */
-		*((uint64_t *)arg) |= VHOST_KERNEL_GUEST_OFFLOADS_MASK;
-		*((uint64_t *)arg) |= VHOST_KERNEL_HOST_OFFLOADS_MASK;
+		if (features & IFF_VNET_HDR) {
+			*((uint64_t *)arg) |= VHOST_KERNEL_GUEST_OFFLOADS_MASK;
+			*((uint64_t *)arg) |= VHOST_KERNEL_HOST_OFFLOADS_MASK;
+		}
 
 		/* vhost_kernel will not declare this feature, but it does
 		 * support multi-queue.
 		 */
-		if (tap_supporte_mq())
+		if (features & IFF_MULTI_QUEUE)
 			*(uint64_t *)arg |= (1ull << VIRTIO_NET_F_MQ);
 	}
 
@@ -380,7 +384,8 @@ vhost_kernel_enable_queue_pair(struct virtio_user_dev *dev,
 	else
 		hdr_size = sizeof(struct virtio_net_hdr);
 
-	tapfd = vhost_kernel_open_tap(&dev->ifname, hdr_size, req_mq);
+	tapfd = vhost_kernel_open_tap(&dev->ifname, hdr_size, req_mq,
+			 (char *)dev->mac_addr, dev->features);
 	if (tapfd < 0) {
 		PMD_DRV_LOG(ERR, "fail to open tap for vhost kernel");
 		return -1;
diff --git a/drivers/net/virtio/virtio_user/vhost_kernel_tap.c b/drivers/net/virtio/virtio_user/vhost_kernel_tap.c
index 689a5cf..e9ee774 100644
--- a/drivers/net/virtio/virtio_user/vhost_kernel_tap.c
+++ b/drivers/net/virtio/virtio_user/vhost_kernel_tap.c
@@ -36,26 +36,64 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <net/if.h>
+#include <net/if_arp.h>
 #include <errno.h>
 #include <string.h>
 #include <limits.h>
 
+#include <rte_ether.h>
+
 #include "vhost_kernel_tap.h"
 #include "../virtio_logs.h"
+#include "../virtio_pci.h"
+
+static int
+vhost_kernel_tap_set_offload(int fd, uint64_t features)
+{
+	unsigned int offload = 0;
+
+	if (features & (1ULL << VIRTIO_NET_F_GUEST_CSUM)) {
+		offload |= TUN_F_CSUM;
+		if (features & (1ULL << VIRTIO_NET_F_GUEST_TSO4))
+			offload |= TUN_F_TSO4;
+		if (features & (1ULL << VIRTIO_NET_F_GUEST_TSO6))
+			offload |= TUN_F_TSO6;
+		if (features & ((1ULL << VIRTIO_NET_F_GUEST_TSO4) |
+			(1ULL << VIRTIO_NET_F_GUEST_TSO6)) &&
+			(features & (1ULL << VIRTIO_NET_F_GUEST_ECN)))
+			offload |= TUN_F_TSO_ECN;
+		if (features & (1ULL << VIRTIO_NET_F_GUEST_UFO))
+			offload |= TUN_F_UFO;
+	}
+
+	if (offload != 0) {
+		/* Check if our kernel supports TUNSETOFFLOAD */
+		if (ioctl(fd, TUNSETOFFLOAD, 0) != 0 && errno == EINVAL) {
+			PMD_DRV_LOG(ERR, "Kernel does't support TUNSETOFFLOAD\n");
+			return -ENOTSUP;
+		}
+
+		if (ioctl(fd, TUNSETOFFLOAD, offload) != 0) {
+			offload &= ~TUN_F_UFO;
+			if (ioctl(fd, TUNSETOFFLOAD, offload) != 0) {
+				PMD_DRV_LOG(ERR, "TUNSETOFFLOAD ioctl() failed: %s\n",
+					strerror(errno));
+				return -1;
+			}
+		}
+	}
+
+	return 0;
+}
 
 int
-vhost_kernel_open_tap(char **p_ifname, int hdr_size, int req_mq)
+vhost_kernel_open_tap(char **p_ifname, int hdr_size, int req_mq,
+			 const char *mac, uint64_t features)
 {
 	unsigned int tap_features;
 	int sndbuf = INT_MAX;
 	struct ifreq ifr;
 	int tapfd;
-	unsigned int offload =
-			TUN_F_CSUM |
-			TUN_F_TSO4 |
-			TUN_F_TSO6 |
-			TUN_F_TSO_ECN |
-			TUN_F_UFO;
 
 	/* TODO:
 	 * 1. verify we can get/set vnet_hdr_len, tap_probe_vnet_hdr_len
@@ -115,13 +153,15 @@ vhost_kernel_open_tap(char **p_ifname, int hdr_size, int req_mq)
 		goto error;
 	}
 
-	/* TODO: before set the offload capabilities, we'd better (1) check
-	 * negotiated features to see if necessary to offload; (2) query tap
-	 * to see if it supports the offload capabilities.
-	 */
-	if (ioctl(tapfd, TUNSETOFFLOAD, offload) != 0)
-		PMD_DRV_LOG(ERR, "TUNSETOFFLOAD ioctl() failed: %s",
-			   strerror(errno));
+	vhost_kernel_tap_set_offload(tapfd, features);
+
+	memset(&ifr, 0, sizeof(ifr));
+	ifr.ifr_hwaddr.sa_family = ARPHRD_ETHER;
+	memcpy(ifr.ifr_hwaddr.sa_data, mac, ETHER_ADDR_LEN);
+	if (ioctl(tapfd, SIOCSIFHWADDR, (void *)&ifr) == -1) {
+		PMD_DRV_LOG(ERR, "SIOCSIFHWADDR failed: %s", strerror(errno));
+		goto error;
+	}
 
 	if (!(*p_ifname))
 		*p_ifname = strdup(ifr.ifr_name);
diff --git a/drivers/net/virtio/virtio_user/vhost_kernel_tap.h b/drivers/net/virtio/virtio_user/vhost_kernel_tap.h
index eae340c..ea7a6c9 100644
--- a/drivers/net/virtio/virtio_user/vhost_kernel_tap.h
+++ b/drivers/net/virtio/virtio_user/vhost_kernel_tap.h
@@ -64,4 +64,5 @@
 /* Constants */
 #define PATH_NET_TUN	"/dev/net/tun"
 
-int vhost_kernel_open_tap(char **p_ifname, int hdr_size, int req_mq);
+int vhost_kernel_open_tap(char **p_ifname, int hdr_size, int req_mq,
+			 const char *mac, uint64_t features);
-- 
2.7.4