Re: [PATCH net-next v7 5/6] net: ngbe: add sriov function support

2025年2月8日 09:19，Jakub Kicinski [off-list ref] 写道：

On Thu,  6 Feb 2025 18:37:49 +0800 mengyuanlou wrote:

quoted

static irqreturn_t ngbe_msix_other(int __always_unused irq, void *data)
{
- struct wx *wx = data;
+ struct wx_q_vector *q_vector;
+ struct wx *wx  = data;
+ u32 eicr;

- /* re-enable the original interrupt state, no lsc, no queues */
- if (netif_running(wx->netdev))
- ngbe_irq_enable(wx, false);
+ q_vector = wx->q_vector[0];
+
+ eicr = wx_misc_isb(wx, WX_ISB_MISC);
+
+ if (eicr & NGBE_PX_MISC_IC_VF_MBOX)
+ wx_msg_task(wx);
+
+ if (wx->num_vfs == 7) {
+ napi_schedule_irqoff(&q_vector->napi);
+ ngbe_irq_enable(wx, true);
+ } else {
+ /* re-enable the original interrupt state, no lsc, no queues */
+ if (netif_running(wx->netdev))
+ ngbe_irq_enable(wx, false);
+ }

return IRQ_HANDLED;
}

You need to explain in the commit message what's happening here.

IDK why the num_vfs == 7 is special.

Due to hardware design, when 6 vfs are assigned. 
+------------------------------------------------------------+
|        | pf | pf  | vf5 | vf4 | vf3 | vf2 | vf1 | vf0 | pf |
|--------|----|-----|-----|-----|-----|-----|-----|-----|----|
| vector | 0  | 1   | 2   | 3   | 4   | 5   | 6   | 7   | 8  |
+------------------------------------------------------------+

When 7 vfs are assigned. 
+------------------------------------------------------------+
|        | pf | vf6 | vf5 | vf4 | vf3 | vf2 | vf1 | vf0 | pf |
|--------|----|-----|-----|-----|-----|-----|-----|-----|----|
| vector | 0  | 1   | 2   | 3   | 4   | 5   | 6   | 7   | 8  |
+------------------------------------------------------------+

When num_vfs < 7, pf can use 0 for misc and 1 for queue.
But when num_vfs == 7, vector 1 is assigned to vf6.
1. Alloc 9 irq vectors, but only request_irq for 0 and 8. 
2. Reuse interrupt vector 0.

Also why are you now scheduling NAPI from a misc MSI-X handler?

The code used the second. Misc and queue reuse interrupt vector 0.

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