diff mbox series

[net-next,v9,6/6] vhost/net: Support VIRTIO_NET_F_HASH_REPORT

Message ID 20250307-rss-v9-6-df76624025eb@daynix.com (mailing list archive)
State New
Headers show
Series tun: Introduce virtio-net hashing feature | expand

Commit Message

Akihiko Odaki March 7, 2025, 11:01 a.m. UTC
VIRTIO_NET_F_HASH_REPORT allows to report hash values calculated on the
host. When VHOST_NET_F_VIRTIO_NET_HDR is employed, it will report no
hash values (i.e., the hash_report member is always set to
VIRTIO_NET_HASH_REPORT_NONE). Otherwise, the values reported by the
underlying socket will be reported.

VIRTIO_NET_F_HASH_REPORT requires VIRTIO_F_VERSION_1.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Tested-by: Lei Yang <leiyang@redhat.com>
---
 drivers/vhost/net.c | 49 +++++++++++++++++++++++++++++--------------------
 1 file changed, 29 insertions(+), 20 deletions(-)

Comments

Jason Wang March 10, 2025, 4:43 a.m. UTC | #1
On Fri, Mar 7, 2025 at 7:02 PM Akihiko Odaki <akihiko.odaki@daynix.com> wrote:
>
> VIRTIO_NET_F_HASH_REPORT allows to report hash values calculated on the
> host. When VHOST_NET_F_VIRTIO_NET_HDR is employed, it will report no
> hash values (i.e., the hash_report member is always set to
> VIRTIO_NET_HASH_REPORT_NONE). Otherwise, the values reported by the
> underlying socket will be reported.
>
> VIRTIO_NET_F_HASH_REPORT requires VIRTIO_F_VERSION_1.
>
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> Tested-by: Lei Yang <leiyang@redhat.com>
> ---
>  drivers/vhost/net.c | 49 +++++++++++++++++++++++++++++--------------------
>  1 file changed, 29 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index b9b9e9d40951856d881d77ac74331d914473cd56..16b241b44f89820a42c302f3586ea6bb5e0d4289 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -73,6 +73,7 @@ enum {
>         VHOST_NET_FEATURES = VHOST_FEATURES |
>                          (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
>                          (1ULL << VIRTIO_NET_F_MRG_RXBUF) |
> +                        (1ULL << VIRTIO_NET_F_HASH_REPORT) |
>                          (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
>                          (1ULL << VIRTIO_F_RING_RESET)
>  };
> @@ -1097,9 +1098,11 @@ static void handle_rx(struct vhost_net *net)
>                 .msg_controllen = 0,
>                 .msg_flags = MSG_DONTWAIT,
>         };
> -       struct virtio_net_hdr hdr = {
> -               .flags = 0,
> -               .gso_type = VIRTIO_NET_HDR_GSO_NONE
> +       struct virtio_net_hdr_v1_hash hdr = {
> +               .hdr = {
> +                       .flags = 0,
> +                       .gso_type = VIRTIO_NET_HDR_GSO_NONE
> +               }
>         };
>         size_t total_len = 0;
>         int err, mergeable;
> @@ -1110,7 +1113,6 @@ static void handle_rx(struct vhost_net *net)
>         bool set_num_buffers;
>         struct socket *sock;
>         struct iov_iter fixup;
> -       __virtio16 num_buffers;
>         int recv_pkts = 0;
>
>         mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_RX);
> @@ -1191,30 +1193,30 @@ static void handle_rx(struct vhost_net *net)
>                         vhost_discard_vq_desc(vq, headcount);
>                         continue;
>                 }
> +               hdr.hdr.num_buffers = cpu_to_vhost16(vq, headcount);
>                 /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */
>                 if (unlikely(vhost_hlen)) {
> -                       if (copy_to_iter(&hdr, sizeof(hdr),
> -                                        &fixup) != sizeof(hdr)) {
> +                       if (copy_to_iter(&hdr, vhost_hlen,
> +                                        &fixup) != vhost_hlen) {
>                                 vq_err(vq, "Unable to write vnet_hdr "
>                                        "at addr %p\n", vq->iov->iov_base);
>                                 goto out;

Is this an "issue" specific to RSS/HASH? If it's not, we need a separate patch.

Honestly, I'm not sure if it's too late to fix this.

Others look fine.

Thanks
Akihiko Odaki March 10, 2025, 7:04 a.m. UTC | #2
On 2025/03/10 13:43, Jason Wang wrote:
> On Fri, Mar 7, 2025 at 7:02 PM Akihiko Odaki <akihiko.odaki@daynix.com> wrote:
>>
>> VIRTIO_NET_F_HASH_REPORT allows to report hash values calculated on the
>> host. When VHOST_NET_F_VIRTIO_NET_HDR is employed, it will report no
>> hash values (i.e., the hash_report member is always set to
>> VIRTIO_NET_HASH_REPORT_NONE). Otherwise, the values reported by the
>> underlying socket will be reported.
>>
>> VIRTIO_NET_F_HASH_REPORT requires VIRTIO_F_VERSION_1.
>>
>> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
>> Tested-by: Lei Yang <leiyang@redhat.com>
>> ---
>>   drivers/vhost/net.c | 49 +++++++++++++++++++++++++++++--------------------
>>   1 file changed, 29 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
>> index b9b9e9d40951856d881d77ac74331d914473cd56..16b241b44f89820a42c302f3586ea6bb5e0d4289 100644
>> --- a/drivers/vhost/net.c
>> +++ b/drivers/vhost/net.c
>> @@ -73,6 +73,7 @@ enum {
>>          VHOST_NET_FEATURES = VHOST_FEATURES |
>>                           (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
>>                           (1ULL << VIRTIO_NET_F_MRG_RXBUF) |
>> +                        (1ULL << VIRTIO_NET_F_HASH_REPORT) |
>>                           (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
>>                           (1ULL << VIRTIO_F_RING_RESET)
>>   };
>> @@ -1097,9 +1098,11 @@ static void handle_rx(struct vhost_net *net)
>>                  .msg_controllen = 0,
>>                  .msg_flags = MSG_DONTWAIT,
>>          };
>> -       struct virtio_net_hdr hdr = {
>> -               .flags = 0,
>> -               .gso_type = VIRTIO_NET_HDR_GSO_NONE
>> +       struct virtio_net_hdr_v1_hash hdr = {
>> +               .hdr = {
>> +                       .flags = 0,
>> +                       .gso_type = VIRTIO_NET_HDR_GSO_NONE
>> +               }
>>          };
>>          size_t total_len = 0;
>>          int err, mergeable;
>> @@ -1110,7 +1113,6 @@ static void handle_rx(struct vhost_net *net)
>>          bool set_num_buffers;
>>          struct socket *sock;
>>          struct iov_iter fixup;
>> -       __virtio16 num_buffers;
>>          int recv_pkts = 0;
>>
>>          mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_RX);
>> @@ -1191,30 +1193,30 @@ static void handle_rx(struct vhost_net *net)
>>                          vhost_discard_vq_desc(vq, headcount);
>>                          continue;
>>                  }
>> +               hdr.hdr.num_buffers = cpu_to_vhost16(vq, headcount);
>>                  /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */
>>                  if (unlikely(vhost_hlen)) {
>> -                       if (copy_to_iter(&hdr, sizeof(hdr),
>> -                                        &fixup) != sizeof(hdr)) {
>> +                       if (copy_to_iter(&hdr, vhost_hlen,
>> +                                        &fixup) != vhost_hlen) {
>>                                  vq_err(vq, "Unable to write vnet_hdr "
>>                                         "at addr %p\n", vq->iov->iov_base);
>>                                  goto out;
> 
> Is this an "issue" specific to RSS/HASH? If it's not, we need a separate patch.
> 
> Honestly, I'm not sure if it's too late to fix this.

There is nothing wrong with the current implementation. The current 
implementation fills the header with zero except num_buffers, which it 
fills some real value. This functionality is working fine with 
VIRTIO_NET_F_MRG_RXBUF and VIRTIO_F_VERSION_1, which change the header size.

Now I'm adding VIRTIO_NET_F_HASH_REPORT and it adds the hash_report 
field, which also needs to be initialized with zero, so I'm making sure 
vhost_net will also initialize it.

Regards,
Akihiko Odaki

> 
> Others look fine.
> 
> Thanks
>
diff mbox series

Patch

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index b9b9e9d40951856d881d77ac74331d914473cd56..16b241b44f89820a42c302f3586ea6bb5e0d4289 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -73,6 +73,7 @@  enum {
 	VHOST_NET_FEATURES = VHOST_FEATURES |
 			 (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
 			 (1ULL << VIRTIO_NET_F_MRG_RXBUF) |
+			 (1ULL << VIRTIO_NET_F_HASH_REPORT) |
 			 (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
 			 (1ULL << VIRTIO_F_RING_RESET)
 };
@@ -1097,9 +1098,11 @@  static void handle_rx(struct vhost_net *net)
 		.msg_controllen = 0,
 		.msg_flags = MSG_DONTWAIT,
 	};
-	struct virtio_net_hdr hdr = {
-		.flags = 0,
-		.gso_type = VIRTIO_NET_HDR_GSO_NONE
+	struct virtio_net_hdr_v1_hash hdr = {
+		.hdr = {
+			.flags = 0,
+			.gso_type = VIRTIO_NET_HDR_GSO_NONE
+		}
 	};
 	size_t total_len = 0;
 	int err, mergeable;
@@ -1110,7 +1113,6 @@  static void handle_rx(struct vhost_net *net)
 	bool set_num_buffers;
 	struct socket *sock;
 	struct iov_iter fixup;
-	__virtio16 num_buffers;
 	int recv_pkts = 0;
 
 	mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_RX);
@@ -1191,30 +1193,30 @@  static void handle_rx(struct vhost_net *net)
 			vhost_discard_vq_desc(vq, headcount);
 			continue;
 		}
+		hdr.hdr.num_buffers = cpu_to_vhost16(vq, headcount);
 		/* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */
 		if (unlikely(vhost_hlen)) {
-			if (copy_to_iter(&hdr, sizeof(hdr),
-					 &fixup) != sizeof(hdr)) {
+			if (copy_to_iter(&hdr, vhost_hlen,
+					 &fixup) != vhost_hlen) {
 				vq_err(vq, "Unable to write vnet_hdr "
 				       "at addr %p\n", vq->iov->iov_base);
 				goto out;
 			}
-		} else {
+		} else if (likely(set_num_buffers)) {
 			/* Header came from socket; we'll need to patch
 			 * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF
 			 */
-			iov_iter_advance(&fixup, sizeof(hdr));
+			iov_iter_advance(&fixup, offsetof(struct virtio_net_hdr_v1, num_buffers));
+
+			if (copy_to_iter(&hdr.hdr.num_buffers, sizeof(hdr.hdr.num_buffers),
+					 &fixup) != sizeof(hdr.hdr.num_buffers)) {
+				vq_err(vq, "Failed num_buffers write");
+				vhost_discard_vq_desc(vq, headcount);
+				goto out;
+			}
 		}
 		/* TODO: Should check and handle checksum. */
 
-		num_buffers = cpu_to_vhost16(vq, headcount);
-		if (likely(set_num_buffers) &&
-		    copy_to_iter(&num_buffers, sizeof num_buffers,
-				 &fixup) != sizeof num_buffers) {
-			vq_err(vq, "Failed num_buffers write");
-			vhost_discard_vq_desc(vq, headcount);
-			goto out;
-		}
 		nvq->done_idx += headcount;
 		if (nvq->done_idx > VHOST_NET_BATCH)
 			vhost_net_signal_used(nvq);
@@ -1607,10 +1609,13 @@  static int vhost_net_set_features(struct vhost_net *n, u64 features)
 	size_t vhost_hlen, sock_hlen, hdr_len;
 	int i;
 
-	hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) |
-			       (1ULL << VIRTIO_F_VERSION_1))) ?
-			sizeof(struct virtio_net_hdr_mrg_rxbuf) :
-			sizeof(struct virtio_net_hdr);
+	if (features & (1ULL << VIRTIO_NET_F_HASH_REPORT))
+		hdr_len = sizeof(struct virtio_net_hdr_v1_hash);
+	else if (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) |
+			     (1ULL << VIRTIO_F_VERSION_1)))
+		hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
+	else
+		hdr_len = sizeof(struct virtio_net_hdr);
 	if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) {
 		/* vhost provides vnet_hdr */
 		vhost_hlen = hdr_len;
@@ -1691,6 +1696,10 @@  static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
 			return -EFAULT;
 		if (features & ~VHOST_NET_FEATURES)
 			return -EOPNOTSUPP;
+		if ((features & ((1ULL << VIRTIO_F_VERSION_1) |
+				 (1ULL << VIRTIO_NET_F_HASH_REPORT))) ==
+		    (1ULL << VIRTIO_NET_F_HASH_REPORT))
+			return -EINVAL;
 		return vhost_net_set_features(n, features);
 	case VHOST_GET_BACKEND_FEATURES:
 		features = VHOST_NET_BACKEND_FEATURES;