From: Alexander Bluhm <alexander.bluhm@gmx.net>
Subject: Re: em(4) TSO support -- 2nd try
To: Marcus Glocker <marcus@nazgul.ch>
Cc: tech@openbsd.org
Date: Fri, 16 Feb 2024 14:04:53 +0100

On Thu, Feb 15, 2024 at 08:07:00PM +0100, Marcus Glocker wrote:
> @@ -2403,6 +2429,73 @@ em_free_transmit_structures(struct em_so
>  		    0, que->tx.sc_tx_dma.dma_map->dm_mapsize,
>  		    BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
>  	}
> +}
> +
> +u_int
> +em_tso_setup(struct em_queue *que, struct mbuf *mp, u_int head,
> +    u_int32_t *olinfo_status, u_int32_t *cmd_type_len)
> +{
> +	struct ether_extracted ext;
> +	struct e1000_adv_tx_context_desc *TD;
> +	uint32_t vlan_macip_lens = 0, type_tucmd_mlhl = 0, mss_l4len_idx = 0;
> +
> +	*olinfo_status = 0;
> +	*cmd_type_len = 0;
> +	TD = (struct e1000_adv_tx_context_desc *)&que->tx.sc_tx_desc_ring[head];
> +
> +#if NVLAN > 0
> +	if (ISSET(mp->m_flags, M_VLANTAG)) {
> +		uint32_t vtag = mp->m_pkthdr.ether_vtag;
> +		vlan_macip_lens |= vtag << E1000_ADVTXD_VLAN_SHIFT;
> +		*cmd_type_len |= E1000_ADVTXD_DCMD_VLE;
> +	}
> +#endif
> +
> +	ether_extract_headers(mp, &ext);
> +	if (ext.tcp == NULL)
> +		goto out;
> +
> +	vlan_macip_lens |= (sizeof(*ext.eh) << E1000_ADVTXD_MACLEN_SHIFT);
> +
> +	if (ext.ip4) {
> +		type_tucmd_mlhl |= E1000_ADVTXD_TUCMD_IPV4;
> +		*olinfo_status |= E1000_TXD_POPTS_IXSM << 8;
> +#ifdef INET6
> +	} else if (ext.ip6) {
> +		type_tucmd_mlhl |= E1000_ADVTXD_TUCMD_IPV6;
> +#endif
> +	} else {
> +		goto out;
> +	}
> +
> +	*cmd_type_len |= E1000_ADVTXD_DTYP_DATA | E1000_ADVTXD_DCMD_IFCS;
> +	*cmd_type_len |= E1000_ADVTXD_DCMD_DEXT | E1000_ADVTXD_DCMD_TSE;
> +	*olinfo_status |= ext.paylen << E1000_ADVTXD_PAYLEN_SHIFT;
> +	vlan_macip_lens |= ext.iphlen;
> +	type_tucmd_mlhl |= E1000_ADVTXD_DCMD_DEXT | E1000_ADVTXD_DTYP_CTXT;
> +
> +	type_tucmd_mlhl |= E1000_ADVTXD_TUCMD_L4T_TCP;
> +	*olinfo_status |= E1000_TXD_POPTS_TXSM << 8;
> +
> +	mss_l4len_idx |= mp->m_pkthdr.ph_mss << E1000_ADVTXD_MSS_SHIFT;
> +	mss_l4len_idx |= (ext.tcp->th_off << 2) << E1000_ADVTXD_L4LEN_SHIFT;

Here it crashes on sparc64.  Use ext.tcphlen.

> +	/* 82575 needs the queue index added */
> +	if (que->sc->hw.mac_type == em_82575)
> +		mss_l4len_idx |= (que->me & 0xff) << 4;
> +
> +	htolem32(&TD->vlan_macip_lens, vlan_macip_lens);
> +	htolem32(&TD->type_tucmd_mlhl, type_tucmd_mlhl);
> +	htolem32(&TD->u.seqnum_seed, 0);
> +	htolem32(&TD->mss_l4len_idx, mss_l4len_idx);
> +
> +	tcpstat_add(tcps_outpkttso, (ext.paylen + mp->m_pkthdr.ph_mss - 1) /
> +	    mp->m_pkthdr.ph_mss);
> +
> +	return 1;
> +
> +out:
> +	tcpstat_inc(tcps_outbadtso);
> +	return 0;
>  }
>  
>  u_int
> Index: dev/pci/if_em.h
> ===================================================================
> RCS file: /cvs/src/sys/dev/pci/if_em.h,v
> diff -u -p -u -p -r1.82 if_em.h
> --- dev/pci/if_em.h	28 Jan 2024 18:42:58 -0000	1.82
> +++ dev/pci/if_em.h	15 Feb 2024 18:33:35 -0000
> @@ -55,11 +55,14 @@ POSSIBILITY OF SUCH DAMAGE.
>  
>  #include <net/if.h>
>  #include <net/if_media.h>
> +#include <net/route.h>
>  
>  #include <netinet/in.h>
>  #include <netinet/ip.h>
>  #include <netinet/if_ether.h>
>  #include <netinet/tcp.h>
> +#include <netinet/tcp_timer.h>
> +#include <netinet/tcp_var.h>
>  #include <netinet/udp.h>
>  
>  #if NBPFILTER > 0
> @@ -269,6 +272,7 @@ typedef int	boolean_t;
>  
>  #define EM_MAX_SCATTER		64
>  #define EM_TSO_SIZE		65535
> +#define EM_TSO_SEG_SIZE		4096	/* Max dma segment size */
>  
>  struct em_packet {
>  	int		 pkt_eop;	/* Index of the desc to watch */
> Index: dev/pci/if_em_hw.h
> ===================================================================
> RCS file: /cvs/src/sys/dev/pci/if_em_hw.h,v
> diff -u -p -u -p -r1.92 if_em_hw.h
> --- dev/pci/if_em_hw.h	28 Jan 2024 18:42:58 -0000	1.92
> +++ dev/pci/if_em_hw.h	15 Feb 2024 18:33:36 -0000
> @@ -2150,6 +2150,7 @@ struct e1000_adv_tx_context_desc {
>  #define E1000_ADVTXD_DCMD_IFCS	0x02000000 /* Insert FCS (Ethernet CRC) */
>  #define E1000_ADVTXD_DCMD_DEXT	0x20000000 /* Descriptor extension (1=Adv) */
>  #define E1000_ADVTXD_DCMD_VLE	0x40000000 /* VLAN pkt enable */
> +#define E1000_ADVTXD_DCMD_TSE	0x80000000 /* TCP Seg enable */
>  #define E1000_ADVTXD_PAYLEN_SHIFT	14 /* Adv desc PAYLEN shift */
>  
>  /* Adv Transmit Descriptor Config Masks */
> @@ -2159,6 +2160,10 @@ struct e1000_adv_tx_context_desc {
>  #define E1000_ADVTXD_TUCMD_IPV6		0x00000000  /* IP Packet Type: 0=IPv6 */
>  #define E1000_ADVTXD_TUCMD_L4T_UDP	0x00000000  /* L4 Packet TYPE of UDP */
>  #define E1000_ADVTXD_TUCMD_L4T_TCP	0x00000800  /* L4 Packet TYPE of TCP */
> +
> +/* Req requires Markers and CRC */
> +#define E1000_ADVTXD_L4LEN_SHIFT	8  /* Adv ctxt L4LEN shift */
> +#define E1000_ADVTXD_MSS_SHIFT		16 /* Adv ctxt MSS shift */
>  
>  /* Multiple Receive Queue Control */
>  #define E1000_MRQC_ENABLE_MASK              0x00000003