Re: [Qemu-devel] [PATCH] ioapic: clear irq_eoi when updating the ioapic redirect table entry

[Peter Xu <peterx@redhat.com>]

On Mon, Jun 24, 2019 at 08:16:35AM -0700, Li Qiang wrote:
> irq_eoi is used to count the number of irq injected during eoi
> broadcast. It should be set to 0 when updating the ioapic's redirect
> table entry.
> 
> Suggested-by: Peter Xu <peterx@redhat.com>
> Signed-off-by: Li Qiang <liq3ea@163.com>
> ---
>  hw/intc/ioapic.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/hw/intc/ioapic.c b/hw/intc/ioapic.c
> index 7074489fdf..db9e518602 100644
> --- a/hw/intc/ioapic.c
> +++ b/hw/intc/ioapic.c
> @@ -380,6 +380,7 @@ ioapic_mem_write(void *opaque, hwaddr addr, uint64_t val,
>                  /* restore RO bits */
>                  s->ioredtbl[index] &= IOAPIC_RW_BITS;
>                  s->ioredtbl[index] |= ro_bits;
> +                s->irq_eoi[index] = 0;

It'll be cleared for twice for each ioapic entry because it only
supports 32bit write to these registers.  Though it seems fine, e.g.,
when the guest only want to update the vector info we should still
clear it:

Reviewed-by: Peter Xu <peterx@redhat.com>

>                  ioapic_fix_edge_remote_irr(&s->ioredtbl[index]);
>                  ioapic_service(s);
>              }
> -- 
> 2.17.1
> 
> 

Regards,

-- 
Peter Xu