Re: [PATCH 11/11] hw/intc/loongarch_ipi: Fix mail send and any send function

[Richard Henderson]

On 7/1/22 15:04, Xiaojuan Yang wrote:
> By the document of ipi mailsend device, byte is written only when the mask bit
> is 0. The original code discards mask bit and overwrite the data always, this
> patch fixes the issue.
>
> Signed-off-by: Xiaojuan Yang <yangxiaojuan@loongson.cn>
> ---
>   hw/intc/loongarch_ipi.c | 45 ++++++++++++++++++++++-------------------
>   1 file changed, 24 insertions(+), 21 deletions(-)
>
> diff --git a/hw/intc/loongarch_ipi.c b/hw/intc/loongarch_ipi.c
> index 553e88703d..e4b1fb5366 100644
> --- a/hw/intc/loongarch_ipi.c
> +++ b/hw/intc/loongarch_ipi.c
> @@ -50,35 +50,40 @@ static uint64_t loongarch_ipi_readl(void *opaque, hwaddr 
> addr, unsigned size)
>       return ret;
>   }
>   
> -static int get_ipi_data(target_ulong val)
> +static void send_ipi_data(CPULoongArchState *env, target_ulong val, 
> target_ulong addr)
>   {
>       int i, mask, data;
>   
> -    data = val >> 32;
> -    mask = (val >> 27) & 0xf;
> -
> +    data = address_space_ldl(&env->address_space_iocsr, addr,
> +                             MEMTXATTRS_UNSPECIFIED, NULL);
> +    mask  = 0;
>       for (i = 0; i < 4; i++) {
> -        if ((mask >> i) & 1) {
> -            data &= ~(0xff << (i * 8));
> +        /* bit 27 - 30 is mask for byte write */
> +        if (val & (0x1UL << (27 + i))) {

UL suffix is never correct, since it means different things on different hosts.
Anyway, you don't any suffix here.

How often does mask == 0, so that all of val is written?  In which case you could skip the 
load.

r~