Re: [PATCH v10 8/8] apic: disable reentrancy detection for apic-msi

[Michael S. Tsirkin]

On Thu, Apr 27, 2023 at 05:10:13PM -0400, Alexander Bulekov wrote:
> As the code is designed for re-entrant calls to apic-msi, mark apic-msi
> as reentrancy-safe.
> 
> Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
> Reviewed-by: Darren Kenny <darren.kenny@oracle.com>

Acked-by: Michael S. Tsirkin <mst@redhat.com>


feel free to merge with rest of patchset - who's going to
merge it btw?

> ---
>  hw/intc/apic.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/hw/intc/apic.c b/hw/intc/apic.c
> index 20b5a94073..ac3d47d231 100644
> --- a/hw/intc/apic.c
> +++ b/hw/intc/apic.c
> @@ -885,6 +885,13 @@ static void apic_realize(DeviceState *dev, Error **errp)
>      memory_region_init_io(&s->io_memory, OBJECT(s), &apic_io_ops, s, 
> "apic-msi",
>                            APIC_SPACE_SIZE);
>  
> +    /*
> +     * apic-msi's apic_mem_write can call into ioapic_eoi_broadcast, which 
> can
> +     * write back to apic-msi. As such mark the apic-msi region re-entrancy
> +     * safe.
> +     */
> +    s->io_memory.disable_reentrancy_guard = true;
> +
>      s->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, apic_timer, s);
>      local_apics[s->id] = s;
>  
> -- 
> 2.39.0