qemu-devel
[Top][All Lists]
Advanced
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH for 8.0] igb: Save more Tx states

From: Akihiko Odaki
Subject: Re: [PATCH for 8.0] igb: Save more Tx states
Date: Fri, 17 Mar 2023 23:20:30 +0900
User-agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 
On 2023/03/17 22:08, Sriram Yagnaraman wrote:




-----Original Message-----
From: Akihiko Odaki <akihiko.odaki@daynix.com>
Sent: Friday, 17 March 2023 13:25
Cc: qemu-devel@nongnu.org; Jason Wang <jasowang@redhat.com>; Dmitry
Fleytman <dmitry.fleytman@gmail.com>; quintela@redhat.com; Philippe
Mathieu-Daudé <philmd@linaro.org>; Sriram Yagnaraman
<sriram.yagnaraman@est.tech>; Akihiko Odaki <akihiko.odaki@daynix.com>
Subject: [PATCH for 8.0] igb: Save more Tx states

The current implementation of igb uses only part of a advanced Tx context
descriptor and first data descriptor because it misses some features and sniffs
the trait of the packet instead of respecting the packet type specified in the
descriptor. However, we will certainly need the entire Tx context descriptor
when we update igb to respect these ignored fields. Save the entire context
descriptor and first data descriptor except the buffer address to prepare for
such a change.

This also introduces the distinction of contexts with different indexes, which
was not present in e1000e but in igb.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
Supersedes: <20230316155707.27007-1-akihiko.odaki@daynix.com>

  hw/net/igb.c      | 25 ++++++++++++++++++-------
  hw/net/igb_core.c | 36 +++++++++++++++++++-----------------
  hw/net/igb_core.h |  8 +++-----
  3 files changed, 40 insertions(+), 29 deletions(-)

diff --git a/hw/net/igb.c b/hw/net/igb.c index c6d753df87..7c05896325
100644
--- a/hw/net/igb.c
+++ b/hw/net/igb.c
@@ -502,16 +502,27 @@ static int igb_post_load(void *opaque, int
version_id)
      return igb_core_post_load(&s->core);  }

-static const VMStateDescription igb_vmstate_tx = {
-    .name = "igb-tx",
+static const VMStateDescription igb_vmstate_tx_ctx = {
+    .name = "igb-tx-ctx",
      .version_id = 1,
      .minimum_version_id = 1,
      .fields = (VMStateField[]) {
-        VMSTATE_UINT16(vlan, struct igb_tx),
-        VMSTATE_UINT16(mss, struct igb_tx),
-        VMSTATE_BOOL(tse, struct igb_tx),
-        VMSTATE_BOOL(ixsm, struct igb_tx),
-        VMSTATE_BOOL(txsm, struct igb_tx),
+        VMSTATE_UINT32(vlan_macip_lens, struct e1000_adv_tx_context_desc),
+        VMSTATE_UINT32(seqnum_seed, struct e1000_adv_tx_context_desc),
+        VMSTATE_UINT32(type_tucmd_mlhl, struct
e1000_adv_tx_context_desc),
+        VMSTATE_UINT32(mss_l4len_idx, struct e1000_adv_tx_context_desc),
+    }
+};
+
+static const VMStateDescription igb_vmstate_tx = {
+    .name = "igb-tx",
+    .version_id = 2,
+    .minimum_version_id = 2,
+    .fields = (VMStateField[]) {
+        VMSTATE_STRUCT_ARRAY(ctx, struct igb_tx, 2, 0, igb_vmstate_tx_ctx,
+                             struct e1000_adv_tx_context_desc),
+        VMSTATE_UINT32(first_cmd_type_len, struct igb_tx),
+        VMSTATE_UINT32(first_olinfo_status, struct igb_tx),
          VMSTATE_BOOL(first, struct igb_tx),
          VMSTATE_BOOL(skip_cp, struct igb_tx),
          VMSTATE_END_OF_LIST()
diff --git a/hw/net/igb_core.c b/hw/net/igb_core.c index
a7c7bfdc75..36027c2b54 100644
--- a/hw/net/igb_core.c
+++ b/hw/net/igb_core.c
@@ -389,8 +389,10 @@ igb_rss_parse_packet(IGBCore *core, struct NetRxPkt
*pkt, bool tx,  static bool  igb_setup_tx_offloads(IGBCore *core, struct igb_tx
*tx)  {
-    if (tx->tse) {
-        if (!net_tx_pkt_build_vheader(tx->tx_pkt, true, true, tx->mss)) {
+    if (tx->first_cmd_type_len & E1000_ADVTXD_DCMD_TSE) {
+        uint32_t idx = (tx->first_olinfo_status >> 4) & 1;


[...] More below


+        uint32_t mss = tx->ctx[idx].mss_l4len_idx >> 16;
+        if (!net_tx_pkt_build_vheader(tx->tx_pkt, true, true, mss)) {
              return false;
          }

@@ -399,13 +401,13 @@ igb_setup_tx_offloads(IGBCore *core, struct igb_tx
*tx)
          return true;
      }

-    if (tx->txsm) {
+    if (tx->first_olinfo_status & E1000_ADVTXD_POTS_TXSM) {
          if (!net_tx_pkt_build_vheader(tx->tx_pkt, false, true, 0)) {
              return false;
          }
      }

-    if (tx->ixsm) {
+    if (tx->first_olinfo_status & E1000_ADVTXD_POTS_IXSM) {
          net_tx_pkt_update_ip_hdr_checksum(tx->tx_pkt);
      }

@@ -527,7 +529,7 @@ igb_process_tx_desc(IGBCore *core,  {
      struct e1000_adv_tx_context_desc *tx_ctx_desc;
      uint32_t cmd_type_len;
-    uint32_t olinfo_status;
+    uint32_t idx;
      uint64_t buffer_addr;
      uint16_t length;

@@ -538,20 +540,19 @@ igb_process_tx_desc(IGBCore *core,
              E1000_ADVTXD_DTYP_DATA) {
              /* advanced transmit data descriptor */
              if (tx->first) {
-                olinfo_status = le32_to_cpu(tx_desc->read.olinfo_status);
-
-                tx->tse = !!(cmd_type_len & E1000_ADVTXD_DCMD_TSE);
-                tx->ixsm = !!(olinfo_status & E1000_ADVTXD_POTS_IXSM);
-                tx->txsm = !!(olinfo_status & E1000_ADVTXD_POTS_TXSM);
-
+                tx->first_cmd_type_len = cmd_type_len;
+                tx->first_olinfo_status =
+ le32_to_cpu(tx_desc->read.olinfo_status);
                  tx->first = false;
              }
          } else if ((cmd_type_len & E1000_ADVTXD_DTYP_CTXT) ==
                     E1000_ADVTXD_DTYP_CTXT) {
              /* advanced transmit context descriptor */
              tx_ctx_desc = (struct e1000_adv_tx_context_desc *)tx_desc;
-            tx->vlan = le32_to_cpu(tx_ctx_desc->vlan_macip_lens) >> 16;
-            tx->mss = le32_to_cpu(tx_ctx_desc->mss_l4len_idx) >> 16;
+            idx = (tx_ctx_desc->mss_l4len_idx >> 4) & 1;


I do not know if there are any other drivers that use more than 2 contexts, but 
as I read 7.2.2.2.11 IDX (3), IDX is a 3 bit field.
The above line will interpret 3, 5 and 7 as 1 for e.g.


7.2.1.4 "Transmit Contexts" says:
> The 82576 supports 32 context register sets on-chip (two per queue)
DPDK also uses only two contexts while its design is extensible and can use more if the hardware allows. Therefore, it can be concluded that the device actually has only two contexts.
I don't know why IDX is defined as 3-bit field, but I think it's safe to ignore the other two bits as we do for the other reserved bits. 




+            tx->ctx[idx].vlan_macip_lens = le32_to_cpu(tx_ctx_desc-

vlan_macip_lens);

+            tx->ctx[idx].seqnum_seed = le32_to_cpu(tx_ctx_desc->seqnum_seed);
+            tx->ctx[idx].type_tucmd_mlhl = le32_to_cpu(tx_ctx_desc-

type_tucmd_mlhl);

+            tx->ctx[idx].mss_l4len_idx =
+ le32_to_cpu(tx_ctx_desc->mss_l4len_idx);
              return;
          } else {
              /* unknown descriptor type */ @@ -575,8 +576,10 @@
igb_process_tx_desc(IGBCore *core,
      if (cmd_type_len & E1000_TXD_CMD_EOP) {
          if (!tx->skip_cp && net_tx_pkt_parse(tx->tx_pkt)) {
              if (cmd_type_len & E1000_TXD_CMD_VLE) {
-                net_tx_pkt_setup_vlan_header_ex(tx->tx_pkt, tx->vlan,
-                    core->mac[VET] & 0xffff);
+                idx = (tx->first_olinfo_status >> 4) & 1;
+                uint16_t vlan = tx->ctx[idx].vlan_macip_lens >> 16;
+                uint16_t vet = core->mac[VET] & 0xffff;
+                net_tx_pkt_setup_vlan_header_ex(tx->tx_pkt, vlan, vet);
              }
              if (igb_tx_pkt_send(core, tx, queue_index)) {
                  igb_on_tx_done_update_stats(core, tx->tx_pkt); @@ -4024,8
+4027,7 @@ static void igb_reset(IGBCore *core, bool sw)
      for (i = 0; i < ARRAY_SIZE(core->tx); i++) {
          tx = &core->tx[i];
          net_tx_pkt_reset(tx->tx_pkt);
-        tx->vlan = 0;
-        tx->mss = 0;
+        memset(&tx->ctx, 0, sizeof(tx->ctx));
          tx->tse = false;
          tx->ixsm = false;
          tx->txsm = false;
diff --git a/hw/net/igb_core.h b/hw/net/igb_core.h index
814c1e264b..8914e0b801 100644
--- a/hw/net/igb_core.h
+++ b/hw/net/igb_core.h
@@ -72,11 +72,9 @@ struct IGBCore {
      QEMUTimer *autoneg_timer;

      struct igb_tx {
-        uint16_t vlan;  /* VLAN Tag */
-        uint16_t mss;   /* Maximum Segment Size */
-        bool tse;       /* TCP/UDP Segmentation Enable */
-        bool ixsm;      /* Insert IP Checksum */
-        bool txsm;      /* Insert TCP/UDP Checksum */
+        struct e1000_adv_tx_context_desc ctx[2];
+        uint32_t first_cmd_type_len;
+        uint32_t first_olinfo_status;

          bool first;
          bool skip_cp;
--
2.39.2
reply via email to
[Prev in Thread] Current Thread [Next in Thread]