Re: [PATCH v5 3/7] igb: Implement TRL register write and configuration

[Akihiko Odaki]

On 2026/06/17 7:35, Josh Hilke wrote:

Implement write handlers for TLDQSEL and TRLRC registers to allow the
guest to configure Transmit Rate Limiting. Translate the register Rate
Factor into a physical target rate (bytes/sec) per queue.  Disable TRL
and clear timers when the link status changes or when TRL is disabled by
the guest.

Signed-off-by: Josh Hilke <jrhi...@google.com>
---
  hw/net/igb_core.c | 38 +++++++++++++++++++++++++++++++++++++-
  1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/hw/net/igb_core.c b/hw/net/igb_core.c
index 44e8e58..fb31e37 100644
--- a/hw/net/igb_core.c
+++ b/hw/net/igb_core.c
@@ -2145,11 +2145,21 @@ static void igb_trl_reset(IGBCore *core)
      }
  }

+static void igb_trl_disable(IGBTrlQueue *q)

+{
+    q->trlrc &= ~E1000_TRLRC_RS_ENA;
+    timer_del(q->timer);

Don't do timer_del(q->timer) here; it will dismiss the pending request.

Regards,
Akihiko Odaki

+}
+
  void igb_core_set_link_status(IGBCore *core)
  {
      NetClientState *nc = qemu_get_queue(core->owner_nic);
      uint32_t old_status = core->mac[STATUS];

+ for (int i = 0; i < IGB_NUM_QUEUES; i++) {

+        igb_trl_disable(&core->trl[i]);
+    }
+
      trace_e1000e_link_status_changed(nc->link_down ? false : true);

if (nc->link_down) {

@@ -2632,6 +2642,29 @@ static void igb_set_vtivar(IGBCore *core, int index, 
uint32_t val)
       */
  }

+static uint32_t igb_get_trlrc(IGBCore *core, int index)

+{
+    const unsigned int qidx = core->mac[TRLDQSEL];
+
+    return core->trl[qidx].trlrc;
+}
+
+static void igb_set_trldqsel(IGBCore *core, int index, uint32_t val)
+{
+    core->mac[index] = extract32(val, 0, 4);
+}
+
+static void igb_set_trlrc(IGBCore *core, int index, uint32_t val)
+{
+    const unsigned int qidx = core->mac[TRLDQSEL];
+
+    core->trl[qidx].trlrc = val;
+
+    if (!igb_trl_enabled(&core->trl[qidx])) {
+        igb_trl_disable(&core->trl[qidx]);
+    }
+}
+
  static inline void
  igb_autoneg_timer(void *opaque)
  {
@@ -3687,6 +3720,7 @@ static const readops igb_macreg_readops[] = {
      [RQDPC15] = igb_mac_read_clr4,
      [VTIVAR ... VTIVAR + 7] = igb_mac_readreg,
      [VTIVAR_MISC ... VTIVAR_MISC + 7] = igb_mac_readreg,
+    [TRLRC] = igb_get_trlrc,
  };
  enum { IGB_NREADOPS = ARRAY_SIZE(igb_macreg_readops) };

@@ -4135,7 +4169,9 @@ static const writeops igb_macreg_writeops[] = {

      [PVTEICR6] = igb_set_vteicr,
      [PVTEICR7] = igb_set_vteicr,
      [VTIVAR ... VTIVAR + 7] = igb_set_vtivar,
-    [VTIVAR_MISC ... VTIVAR_MISC + 7] = igb_mac_writereg
+    [VTIVAR_MISC ... VTIVAR_MISC + 7] = igb_mac_writereg,
+    [TRLDQSEL] = igb_set_trldqsel,
+    [TRLRC]    = igb_set_trlrc,
  };
  enum { IGB_NWRITEOPS = ARRAY_SIZE(igb_macreg_writeops) };