drivers/net/virtio_net.c | 15 +++++++++++++-- include/uapi/linux/virtio_net.h | 3 ++- 2 files changed, 15 insertions(+), 3 deletions(-)
From: "Michael S. Tsirkin" <mst@redhat.com>
Changing alignment of header would mean it's no longer safe to cast a
2 byte aligned pointer between formats. Use two 16 bit fields to make
it 2 byte aligned as previously.
This fixes the performance regression since
commit ("virtio_net: enable gso over UDP tunnel support.") as it uses
virtio_net_hdr_v1_hash_tunnel which embeds
virtio_net_hdr_v1_hash. Pktgen in guest + XDP_DROP on TAP + vhost_net
shows the TX PPS is recovered from 2.4Mpps to 4.45Mpps.
Fixes: 56a06bd40fab ("virtio_net: enable gso over UDP tunnel support.")
Cc: stable@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/net/virtio_net.c | 15 +++++++++++++--
include/uapi/linux/virtio_net.h | 3 ++-
2 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index a757cbcab87f..5e998d88db44 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2534,6 +2534,13 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
return NULL;
}
+static inline u32
+virtio_net_hash_value(const struct virtio_net_hdr_v1_hash *hdr_hash)
+{
+ return __le16_to_cpu(hdr_hash->hash_value_lo) |
+ (__le16_to_cpu(hdr_hash->hash_value_hi) << 16);
+}
+
static void virtio_skb_set_hash(const struct virtio_net_hdr_v1_hash *hdr_hash,
struct sk_buff *skb)
{
@@ -2560,7 +2567,7 @@ static void virtio_skb_set_hash(const struct virtio_net_hdr_v1_hash *hdr_hash,
default:
rss_hash_type = PKT_HASH_TYPE_NONE;
}
- skb_set_hash(skb, __le32_to_cpu(hdr_hash->hash_value), rss_hash_type);
+ skb_set_hash(skb, virtio_net_hash_value(hdr_hash), rss_hash_type);
}
static void virtnet_receive_done(struct virtnet_info *vi, struct receive_queue *rq,
@@ -3306,6 +3313,10 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb, bool orphan)
pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
+ /* Make sure it's safe to cast between formats */
+ BUILD_BUG_ON(__alignof__(*hdr) != __alignof__(hdr->hash_hdr));
+ BUILD_BUG_ON(__alignof__(*hdr) != __alignof__(hdr->hash_hdr.hdr));
+
can_push = vi->any_header_sg &&
!((unsigned long)skb->data & (__alignof__(*hdr) - 1)) &&
!skb_header_cloned(skb) && skb_headroom(skb) >= hdr_len;
@@ -6745,7 +6756,7 @@ static int virtnet_xdp_rx_hash(const struct xdp_md *_ctx, u32 *hash,
hash_report = VIRTIO_NET_HASH_REPORT_NONE;
*rss_type = virtnet_xdp_rss_type[hash_report];
- *hash = __le32_to_cpu(hdr_hash->hash_value);
+ *hash = virtio_net_hash_value(hdr_hash);
return 0;
}
diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
index 8bf27ab8bcb4..1db45b01532b 100644
--- a/include/uapi/linux/virtio_net.h
+++ b/include/uapi/linux/virtio_net.h
@@ -193,7 +193,8 @@ struct virtio_net_hdr_v1 {
struct virtio_net_hdr_v1_hash {
struct virtio_net_hdr_v1 hdr;
- __le32 hash_value;
+ __le16 hash_value_lo;
+ __le16 hash_value_hi;
#define VIRTIO_NET_HASH_REPORT_NONE 0
#define VIRTIO_NET_HASH_REPORT_IPv4 1
#define VIRTIO_NET_HASH_REPORT_TCPv4 2
--
2.42.0Hi Jason,
kernel test robot noticed the following build errors:
[auto build test ERROR on net/main]
url: https://github.com/intel-lab-lkp/linux/commits/Jason-Wang/virtio_net-fix-alignment-for-virtio_net_hdr_v1_hash/20251029-092814
base: net/main
patch link: https://lore.kernel.org/r/20251029012434.75576-1-jasowang%40redhat.com
patch subject: [PATCH net] virtio_net: fix alignment for virtio_net_hdr_v1_hash
config: x86_64-kexec (https://download.01.org/0day-ci/archive/20251029/202510292352.dvaYVyZt-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251029/202510292352.dvaYVyZt-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202510292352.dvaYVyZt-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from net/packet/af_packet.c:86:
>> include/linux/virtio_net.h:404:24: error: no member named 'hash_value' in 'struct virtio_net_hdr_v1_hash'
404 | vhdr->hash_hdr.hash_value = 0;
| ~~~~~~~~~~~~~~ ^
1 error generated.
vim +404 include/linux/virtio_net.h
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 376
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 377 /*
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 378 * vlan_hlen always refers to the outermost MAC header. That also
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 379 * means it refers to the only MAC header, if the packet does not carry
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 380 * any encapsulation.
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 381 */
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 382 static inline int
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 383 virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb,
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 384 struct virtio_net_hdr_v1_hash_tunnel *vhdr,
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 385 bool tnl_hdr_negotiated,
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 386 bool little_endian,
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 387 int vlan_hlen)
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 388 {
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 389 struct virtio_net_hdr *hdr = (struct virtio_net_hdr *)vhdr;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 390 unsigned int inner_nh, outer_th;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 391 int tnl_gso_type;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 392 int ret;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 393
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 394 tnl_gso_type = skb_shinfo(skb)->gso_type & (SKB_GSO_UDP_TUNNEL |
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 395 SKB_GSO_UDP_TUNNEL_CSUM);
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 396 if (!tnl_gso_type)
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 397 return virtio_net_hdr_from_skb(skb, hdr, little_endian, false,
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 398 vlan_hlen);
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 399
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 400 /* Tunnel support not negotiated but skb ask for it. */
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 401 if (!tnl_hdr_negotiated)
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 402 return -EINVAL;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 403
b2284768c6b32a Jason Wang 2025-10-22 @404 vhdr->hash_hdr.hash_value = 0;
b2284768c6b32a Jason Wang 2025-10-22 405 vhdr->hash_hdr.hash_report = 0;
b2284768c6b32a Jason Wang 2025-10-22 406 vhdr->hash_hdr.padding = 0;
b2284768c6b32a Jason Wang 2025-10-22 407
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 408 /* Let the basic parsing deal with plain GSO features. */
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 409 skb_shinfo(skb)->gso_type &= ~tnl_gso_type;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 410 ret = virtio_net_hdr_from_skb(skb, hdr, true, false, vlan_hlen);
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 411 skb_shinfo(skb)->gso_type |= tnl_gso_type;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 412 if (ret)
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 413 return ret;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 414
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 415 if (skb->protocol == htons(ETH_P_IPV6))
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 416 hdr->gso_type |= VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV6;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 417 else
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 418 hdr->gso_type |= VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV4;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 419
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 420 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM)
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 421 hdr->flags |= VIRTIO_NET_HDR_F_UDP_TUNNEL_CSUM;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 422
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 423 inner_nh = skb->inner_network_header - skb_headroom(skb);
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 424 outer_th = skb->transport_header - skb_headroom(skb);
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 425 vhdr->inner_nh_offset = cpu_to_le16(inner_nh);
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 426 vhdr->outer_th_offset = cpu_to_le16(outer_th);
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 427 return 0;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 428 }
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 429
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Hi Jason,
kernel test robot noticed the following build errors:
[auto build test ERROR on net/main]
url: https://github.com/intel-lab-lkp/linux/commits/Jason-Wang/virtio_net-fix-alignment-for-virtio_net_hdr_v1_hash/20251029-092814
base: net/main
patch link: https://lore.kernel.org/r/20251029012434.75576-1-jasowang%40redhat.com
patch subject: [PATCH net] virtio_net: fix alignment for virtio_net_hdr_v1_hash
config: openrisc-defconfig (https://download.01.org/0day-ci/archive/20251029/202510292058.zgpkfnPq-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 15.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251029/202510292058.zgpkfnPq-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202510292058.zgpkfnPq-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from net/packet/af_packet.c:86:
include/linux/virtio_net.h: In function 'virtio_net_hdr_tnl_from_skb':
>> include/linux/virtio_net.h:404:24: error: 'struct virtio_net_hdr_v1_hash' has no member named 'hash_value'; did you mean 'hash_value_lo'?
404 | vhdr->hash_hdr.hash_value = 0;
| ^~~~~~~~~~
| hash_value_lo
vim +404 include/linux/virtio_net.h
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 376
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 377 /*
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 378 * vlan_hlen always refers to the outermost MAC header. That also
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 379 * means it refers to the only MAC header, if the packet does not carry
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 380 * any encapsulation.
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 381 */
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 382 static inline int
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 383 virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb,
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 384 struct virtio_net_hdr_v1_hash_tunnel *vhdr,
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 385 bool tnl_hdr_negotiated,
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 386 bool little_endian,
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 387 int vlan_hlen)
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 388 {
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 389 struct virtio_net_hdr *hdr = (struct virtio_net_hdr *)vhdr;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 390 unsigned int inner_nh, outer_th;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 391 int tnl_gso_type;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 392 int ret;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 393
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 394 tnl_gso_type = skb_shinfo(skb)->gso_type & (SKB_GSO_UDP_TUNNEL |
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 395 SKB_GSO_UDP_TUNNEL_CSUM);
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 396 if (!tnl_gso_type)
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 397 return virtio_net_hdr_from_skb(skb, hdr, little_endian, false,
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 398 vlan_hlen);
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 399
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 400 /* Tunnel support not negotiated but skb ask for it. */
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 401 if (!tnl_hdr_negotiated)
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 402 return -EINVAL;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 403
b2284768c6b32a Jason Wang 2025-10-22 @404 vhdr->hash_hdr.hash_value = 0;
b2284768c6b32a Jason Wang 2025-10-22 405 vhdr->hash_hdr.hash_report = 0;
b2284768c6b32a Jason Wang 2025-10-22 406 vhdr->hash_hdr.padding = 0;
b2284768c6b32a Jason Wang 2025-10-22 407
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 408 /* Let the basic parsing deal with plain GSO features. */
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 409 skb_shinfo(skb)->gso_type &= ~tnl_gso_type;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 410 ret = virtio_net_hdr_from_skb(skb, hdr, true, false, vlan_hlen);
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 411 skb_shinfo(skb)->gso_type |= tnl_gso_type;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 412 if (ret)
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 413 return ret;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 414
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 415 if (skb->protocol == htons(ETH_P_IPV6))
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 416 hdr->gso_type |= VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV6;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 417 else
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 418 hdr->gso_type |= VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV4;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 419
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 420 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM)
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 421 hdr->flags |= VIRTIO_NET_HDR_F_UDP_TUNNEL_CSUM;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 422
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 423 inner_nh = skb->inner_network_header - skb_headroom(skb);
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 424 outer_th = skb->transport_header - skb_headroom(skb);
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 425 vhdr->inner_nh_offset = cpu_to_le16(inner_nh);
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 426 vhdr->outer_th_offset = cpu_to_le16(outer_th);
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 427 return 0;
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 428 }
a2fb4bc4e2a6a0 Paolo Abeni 2025-07-08 429
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On 10/29/25 2:24 AM, Jason Wang wrote:
> From: "Michael S. Tsirkin" <mst@redhat.com>
>
> Changing alignment of header would mean it's no longer safe to cast a
> 2 byte aligned pointer between formats. Use two 16 bit fields to make
> it 2 byte aligned as previously.
>
> This fixes the performance regression since
> commit ("virtio_net: enable gso over UDP tunnel support.") as it uses
> virtio_net_hdr_v1_hash_tunnel which embeds
> virtio_net_hdr_v1_hash. Pktgen in guest + XDP_DROP on TAP + vhost_net
> shows the TX PPS is recovered from 2.4Mpps to 4.45Mpps.
>
> Fixes: 56a06bd40fab ("virtio_net: enable gso over UDP tunnel support.")
> Cc: stable@vger.kernel.org
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Whoops, I replied to the older thread before reading this one.
Acked-by: Paolo Abeni <pabeni@redhat.com>
On Wed, Oct 29, 2025 at 4:20 PM Paolo Abeni <pabeni@redhat.com> wrote:
>
> On 10/29/25 2:24 AM, Jason Wang wrote:
> > From: "Michael S. Tsirkin" <mst@redhat.com>
> >
> > Changing alignment of header would mean it's no longer safe to cast a
> > 2 byte aligned pointer between formats. Use two 16 bit fields to make
> > it 2 byte aligned as previously.
> >
> > This fixes the performance regression since
> > commit ("virtio_net: enable gso over UDP tunnel support.") as it uses
> > virtio_net_hdr_v1_hash_tunnel which embeds
> > virtio_net_hdr_v1_hash. Pktgen in guest + XDP_DROP on TAP + vhost_net
> > shows the TX PPS is recovered from 2.4Mpps to 4.45Mpps.
> >
> > Fixes: 56a06bd40fab ("virtio_net: enable gso over UDP tunnel support.")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > Signed-off-by: Jason Wang <jasowang@redhat.com>
>
> Whoops, I replied to the older thread before reading this one.
>
> Acked-by: Paolo Abeni <pabeni@redhat.com>
I apologize, build will be broken since
commit b2284768c6b32aa224ca7d0ef0741beb434f03aa
Author: Jason Wang <jasowang@redhat.com>
Date: Wed Oct 22 11:44:21 2025 +0800
virtio-net: zero unused hash fields
I will prepare a new version.
Btw, it looks like there's an uAPI change that may break builds of the
userspace:
diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
index 8bf27ab8bcb4..1db45b01532b 100644
--- a/include/uapi/linux/virtio_net.h
+++ b/include/uapi/linux/virtio_net.h
@@ -193,7 +193,8 @@ struct virtio_net_hdr_v1 {
struct virtio_net_hdr_v1_hash {
struct virtio_net_hdr_v1 hdr;
- __le32 hash_value;
+ __le16 hash_value_lo;
+ __le16 hash_value_hi;
We can have a kernel only version for this but it probably means we
need a kernel only version for all the future extension of vnet
header?
Thanks
>
On Thu, Oct 30, 2025 at 10:40:13AM +0800, Jason Wang wrote:
> On Wed, Oct 29, 2025 at 4:20 PM Paolo Abeni <pabeni@redhat.com> wrote:
> >
> > On 10/29/25 2:24 AM, Jason Wang wrote:
> > > From: "Michael S. Tsirkin" <mst@redhat.com>
> > >
> > > Changing alignment of header would mean it's no longer safe to cast a
> > > 2 byte aligned pointer between formats. Use two 16 bit fields to make
> > > it 2 byte aligned as previously.
> > >
> > > This fixes the performance regression since
> > > commit ("virtio_net: enable gso over UDP tunnel support.") as it uses
> > > virtio_net_hdr_v1_hash_tunnel which embeds
> > > virtio_net_hdr_v1_hash. Pktgen in guest + XDP_DROP on TAP + vhost_net
> > > shows the TX PPS is recovered from 2.4Mpps to 4.45Mpps.
> > >
> > > Fixes: 56a06bd40fab ("virtio_net: enable gso over UDP tunnel support.")
> > > Cc: stable@vger.kernel.org
> > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > > Signed-off-by: Jason Wang <jasowang@redhat.com>
> >
> > Whoops, I replied to the older thread before reading this one.
> >
> > Acked-by: Paolo Abeni <pabeni@redhat.com>
>
> I apologize, build will be broken since
>
> commit b2284768c6b32aa224ca7d0ef0741beb434f03aa
> Author: Jason Wang <jasowang@redhat.com>
> Date: Wed Oct 22 11:44:21 2025 +0800
>
> virtio-net: zero unused hash fields
>
> I will prepare a new version.
>
> Btw, it looks like there's an uAPI change that may break builds of the
> userspace:
No, I think this has not been out long enough to matter.
QEMU imports linux headers extremely quickly but it can adapt.
> diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
> index 8bf27ab8bcb4..1db45b01532b 100644
> --- a/include/uapi/linux/virtio_net.h
> +++ b/include/uapi/linux/virtio_net.h
> @@ -193,7 +193,8 @@ struct virtio_net_hdr_v1 {
>
> struct virtio_net_hdr_v1_hash {
> struct virtio_net_hdr_v1 hdr;
> - __le32 hash_value;
> + __le16 hash_value_lo;
> + __le16 hash_value_hi;
>
> We can have a kernel only version for this but it probably means we
> need a kernel only version for all the future extension of vnet
> header?
>
> Thanks
>
Let's not complicate things too much please.
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