Re: [PATCH 1/3] hw/openrisc/openrisc_sim: Use IRQ splitter when connecting IRQ to multiple CPUs

[Stafford Horne]

On Fri, Nov 27, 2020 at 10:51:25PM +0000, Peter Maydell wrote:
> openrisc_sim_net_init() attempts to connect the IRQ line from the
> ethernet device to both CPUs in an SMP configuration by simply caling
> sysbus_connect_irq() for it twice.  This doesn't work, because the
> second connection simply overrides the first.
> 
> Fix this by creating a TYPE_SPLIT_IRQ to split the IRQ in the SMP
> case.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  hw/openrisc/openrisc_sim.c | 13 +++++++++++--
>  hw/openrisc/Kconfig        |  1 +
>  2 files changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/openrisc/openrisc_sim.c b/hw/openrisc/openrisc_sim.c
> index d752282e675..a8adf6b70d7 100644
> --- a/hw/openrisc/openrisc_sim.c
> +++ b/hw/openrisc/openrisc_sim.c
> @@ -34,6 +34,7 @@
>  #include "hw/sysbus.h"
>  #include "sysemu/qtest.h"
>  #include "sysemu/reset.h"
> +#include "hw/core/split-irq.h"
>  
>  #define KERNEL_LOAD_ADDR 0x100
>  
> @@ -64,8 +65,16 @@ static void openrisc_sim_net_init(hwaddr base, hwaddr 
> descriptors,
>  
>      s = SYS_BUS_DEVICE(dev);
>      sysbus_realize_and_unref(s, &error_fatal);
> -    for (i = 0; i < num_cpus; i++) {
> -        sysbus_connect_irq(s, 0, cpu_irqs[i][irq_pin]);
> +    if (num_cpus > 1) {
> +        DeviceState *splitter = qdev_new(TYPE_SPLIT_IRQ);
> +        qdev_prop_set_uint32(splitter, "num-lines", num_cpus);
> +        qdev_realize_and_unref(splitter, NULL, &error_fatal);
> +        for (i = 0; i < num_cpus; i++) {
> +            qdev_connect_gpio_out(splitter, i, cpu_irqs[i][irq_pin]);
> +        }
> +        sysbus_connect_irq(s, 0, qdev_get_gpio_in(splitter, 0));
> +    } else {
> +        sysbus_connect_irq(s, 0, cpu_irqs[0][irq_pin]);
>      }
>      sysbus_mmio_map(s, 0, base);
>      sysbus_mmio_map(s, 1, descriptors);
> diff --git a/hw/openrisc/Kconfig b/hw/openrisc/Kconfig
> index 6c1e86884e2..8f284f3ba04 100644
> --- a/hw/openrisc/Kconfig
> +++ b/hw/openrisc/Kconfig
> @@ -3,3 +3,4 @@ config OR1K_SIM
>      select SERIAL
>      select OPENCORES_ETH
>      select OMPIC
> +    select SPLIT_IRQ
> -- 
> 2.20.1


This looks good to me, I don't think I ever tested networking with SMP.  Thanks
for the fix!

Reviewed-by: Stafford Horne <shorne@gmail.com>

Can you help merge the patch? I am not working a queue right now.