Re: [PATCH] ppc/xive: Trigger the pending interrupt for a guest after migration

[Nikhil Kumar Singh <nikhilks@linux.ibm.com>]

On 24/08/26 12:33, Gautam Menghani wrote:


Hi Gautam,

I was going through the implementation and had a small doubt regarding 
the scope of the fix for the TIMA rings. I can see that we are 
explicitly reading and setting the PIPR for TM_QW1_OS:

> +    } else {
> +        uint8_t pipr = tctx->regs[TM_QW1_OS + TM_PIPR];
> +        xive_tctx_pipr_set(tctx, TM_QW1_OS, pipr, 0);
>       }

I guess vmstate_xive_tctx_post_load is a shared device code, I was 
wondering what happens in the case of the other rings? Should we also 
force a re-evaluation for TM_QW3_HV_PHYS or TM_QW2_HV_POOL to avoid 
similar lockups in those configurations? Or is this issue strictly 
coming only in the OS ring in practical scenarios? Please let me know 
your thoughts on this.

Also, one minor suggestion. Since this logic is going inside the else 
block of if (kvm_irqchip_in_kernel()), I feel it would be better if we 
can add a line in the commit message mentioning that this specifically 
fixes state restoration for environments relying on QEMU's emulated XIVE.

Thanks
~ Nikhil