From ed9ecb0415b97b5f9f91f146e1977bb372c74c6d Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 13 Feb 2015 17:13:44 +1030 Subject: [PATCH] virtio: Don't expose legacy net features when VIRTIO_NET_NO_LEGACY defined. In particular, the virtio header always has the u16 num_buffers field. We define a new 'struct virtio_net_hdr_v1' for this (rather than simply calling it 'struct virtio_net_hdr', to avoid nasty type errors if some parts of a project define VIRTIO_NET_NO_LEGACY and some don't. Transitional devices (which can't define VIRTIO_NET_NO_LEGACY) will have to keep using struct virtio_net_hdr_mrg_rxbuf, which has the same byte layout as struct virtio_net_hdr_v1. Signed-off-by: Rusty Russell --- include/uapi/linux/virtio_net.h | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h index b5f1677b291c..4a9b58113d6e 100644 --- a/include/uapi/linux/virtio_net.h +++ b/include/uapi/linux/virtio_net.h @@ -35,7 +35,6 @@ #define VIRTIO_NET_F_CSUM 0 /* Host handles pkts w/ partial csum */ #define VIRTIO_NET_F_GUEST_CSUM 1 /* Guest handles pkts w/ partial csum */ #define VIRTIO_NET_F_MAC 5 /* Host has given MAC address. */ -#define VIRTIO_NET_F_GSO 6 /* Host handles pkts w/ any GSO type */ #define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */ #define VIRTIO_NET_F_GUEST_TSO6 8 /* Guest can handle TSOv6 in. */ #define VIRTIO_NET_F_GUEST_ECN 9 /* Guest can handle TSO[6] w/ ECN in. */ @@ -56,6 +55,10 @@ * Steering */ #define VIRTIO_NET_F_CTRL_MAC_ADDR 23 /* Set MAC address */ +#ifndef VIRTIO_NET_NO_LEGACY +#define VIRTIO_NET_F_GSO 6 /* Host handles pkts w/ any GSO type */ +#endif /* VIRTIO_NET_NO_LEGACY */ + #define VIRTIO_NET_S_LINK_UP 1 /* Link is up */ #define VIRTIO_NET_S_ANNOUNCE 2 /* Announcement is needed */ @@ -71,8 +74,9 @@ struct virtio_net_config { __u16 max_virtqueue_pairs; } __attribute__((packed)); +#ifndef VIRTIO_NET_NO_LEGACY /* This header comes first in the scatter-gather list. - * If VIRTIO_F_ANY_LAYOUT is not negotiated, it must + * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated, it must * be the first element of the scatter-gather list. If you don't * specify GSO or CSUM features, you can simply ignore the header. */ struct virtio_net_hdr { @@ -97,6 +101,30 @@ struct virtio_net_hdr_mrg_rxbuf { struct virtio_net_hdr hdr; __virtio16 num_buffers; /* Number of merged rx buffers */ }; +#else /* ... VIRTIO_NET_NO_LEGACY */ +/* + * This header comes first in the scatter-gather list. If you don't + * specify GSO or CSUM features, you can simply ignore the header. + * + * This is bitwise-equivalent to the legacy struct virtio_net_hdr_mrg_rxbuf. + */ +struct virtio_net_hdr_v1 { +#define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 /* Use csum_start, csum_offset */ +#define VIRTIO_NET_HDR_F_DATA_VALID 2 /* Csum is valid */ + __u8 flags; +#define VIRTIO_NET_HDR_GSO_NONE 0 /* Not a GSO frame */ +#define VIRTIO_NET_HDR_GSO_TCPV4 1 /* GSO frame, IPv4 TCP (TSO) */ +#define VIRTIO_NET_HDR_GSO_UDP 3 /* GSO frame, IPv4 UDP (UFO) */ +#define VIRTIO_NET_HDR_GSO_TCPV6 4 /* GSO frame, IPv6 TCP */ +#define VIRTIO_NET_HDR_GSO_ECN 0x80 /* TCP has ECN set */ + __u8 gso_type; + __virtio16 hdr_len; /* Ethernet + IP + tcp/udp hdrs */ + __virtio16 gso_size; /* Bytes to append to hdr_len per frame */ + __virtio16 csum_start; /* Position to start checksumming from */ + __virtio16 csum_offset; /* Offset after that to place checksum */ + __virtio16 num_buffers; /* Number of merged rx buffers */ +}; +#endif /* ...VIRTIO_NET_NO_LEGACY */ /* * Control virtqueue data structures -- 2.39.2