On 04-Jul-26 12:20 AM, Timur Kristóf wrote:
On 2026. július 3., péntek 20:11:59 közép-európai nyári idő Joshi, Mukul
wrote:
I still haven't found any explanation why we use a doorbell for the CAM in
the first
place? Lijo, Alex, Felix does anybody know that?


If I remember correctly, we weren't sure if the IH_RETRY_CAM_ACK register
would be available under
virtualization. And we were sure doorbells would
work for both bare-metal and virtualization.

Hi Mukul,

Can you clarify that please?

How are retry faults supposed to work under virtualization? Is the interrupt
processed by the guest or the host? Why is the IH_RETRY_CAM_ACK register not
available under virtualization?


For clarification - CAM entries are separate for PF/VF. ACK register also has PF/VF copies. However, in general host driver imposes MMIO register access restrictions to VF, possibly that's the reason.

Please note that IH_RETRY_INT_CAM_CNTL is PF only. With new versions, please make sure to add a VF check for programming.

Thanks,
Lijo

Thanks & best regards,
Timur




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