[PATCH for 8.0] igb: Save more Tx states

Akihiko Odaki posted 1 patch 1 year, 1 month ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/20230317122456.43461-1-akihiko.odaki@daynix.com
Maintainers: Akihiko Odaki <akihiko.odaki@daynix.com>, Jason Wang <jasowang@redhat.com>
There is a newer version of this series
hw/net/igb.c      | 25 ++++++++++++++++++-------
hw/net/igb_core.c | 36 +++++++++++++++++++-----------------
hw/net/igb_core.h |  8 +++-----
3 files changed, 40 insertions(+), 29 deletions(-)
[PATCH for 8.0] igb: Save more Tx states
Posted by Akihiko Odaki 1 year, 1 month ago
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;
+        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;
+            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
RE: [PATCH for 8.0] igb: Save more Tx states
Posted by Sriram Yagnaraman 1 year, 1 month ago

> -----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.

> +            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

Re: [PATCH for 8.0] igb: Save more Tx states
Posted by Akihiko Odaki 1 year, 1 month ago
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
> 

RE: [PATCH for 8.0] igb: Save more Tx states
Posted by Sriram Yagnaraman 1 year, 1 month ago
> -----Original Message-----
> From: Akihiko Odaki <akihiko.odaki@daynix.com>
> Sent: Friday, 17 March 2023 15:21
> To: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
> 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>
> Subject: Re: [PATCH for 8.0] igb: Save more Tx states
> 
> 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.

7.2.1.4 also clearly specifies that "The IDX field contains an index to one of the two queue contexts".
Thanks for replying to my comments.

> 
> >
> >> +            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
> >

LGTM
Reviewed-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
RE: [PATCH for 8.0] igb: Save more Tx states
Posted by Sriram Yagnaraman 1 year ago
> -----Original Message-----
> From: qemu-devel-bounces+sriram.yagnaraman=est.tech@nongnu.org
> <qemu-devel-bounces+sriram.yagnaraman=est.tech@nongnu.org> On Behalf
> Of Sriram Yagnaraman
> Sent: Friday, 17 March 2023 16:26
> To: Akihiko Odaki <akihiko.odaki@daynix.com>
> 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>
> Subject: RE: [PATCH for 8.0] igb: Save more Tx states
> 
> 
> > -----Original Message-----
> > From: Akihiko Odaki <akihiko.odaki@daynix.com>
> > Sent: Friday, 17 March 2023 15:21
> > To: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
> > 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>
> > Subject: Re: [PATCH for 8.0] igb: Save more Tx states
> >
> > 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.
> 
> 7.2.1.4 also clearly specifies that "The IDX field contains an index to one of the
> two queue contexts".
> Thanks for replying to my comments.
> 
> >
> > >
> > >> +            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;

BTW, just noticed you will have to remove the above 3 lines as well. Doesn't compile otherwise.

> > >> 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
> > >
> 
> LGTM
> Reviewed-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>