Re: [PATCH] x86/ioapic: Don't return 0 as valid virq

[Saurabh Singh Sengar]

On Thu, Mar 02, 2023 at 11:34:46AM -0800, Saurabh Sengar wrote:
> Zero is invalid virq and should't be returned as a valid value for
> lower irq bound. If IO-APIC and gsi_top are not initialized return
> the 'from' value as virq.
> 
> Signed-off-by: Saurabh Sengar <ssengar@xxxxxxxxxxxxxxxxxxx>
> ---
>  arch/x86/kernel/apic/io_apic.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
> index a868b76cd3d4..000cc6159b8b 100644
> --- a/arch/x86/kernel/apic/io_apic.c
> +++ b/arch/x86/kernel/apic/io_apic.c
> @@ -2483,9 +2483,11 @@ unsigned int arch_dynirq_lower_bound(unsigned int from)
>  	/*
>  	 * dmar_alloc_hwirq() may be called before setup_IO_APIC(), so use
>  	 * gsi_top if ioapic_dynirq_base hasn't been initialized yet.
> +	 *
> +	 * Incase gsi_top is also not initialized return @from.
>  	 */
>  	if (!ioapic_initialized)
> -		return gsi_top;
> +		return gsi_top ? : from;
>  	/*
>  	 * For DT enabled machines ioapic_dynirq_base is irrelevant and not
>  	 * updated. So simply return @from if ioapic_dynirq_base == 0.
> -- 
> 2.34.1

Hi Maintainers,

May I get your feedback on this patch.

Regards,
Saurabh