On Wed, Dec 21, 2016 at 02:45:53PM +0800, fu....@linaro.org wrote:
[...]

> -     if (is_hyp_mode_available() || !arch_timer_ppi[ARCH_TIMER_VIRT_PPI]) {
> -             bool has_ppi;
> +     if (is_hyp_mode_available() && is_kernel_in_hyp_mode())
> +             return ARCH_TIMER_HYP_PPI;
>  
> -             if (is_kernel_in_hyp_mode()) {
> -                     arch_timer_uses_ppi = ARCH_TIMER_HYP_PPI;
> -                     has_ppi = !!arch_timer_ppi[ARCH_TIMER_HYP_PPI];
> -             } else {
> -                     arch_timer_uses_ppi = ARCH_TIMER_PHYS_SECURE_PPI;
> -                     has_ppi = (!!arch_timer_ppi[ARCH_TIMER_PHYS_SECURE_PPI] 
> ||
> -                                
> !!arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI]);
> -             }
> +     if (arch_timer_ppi[ARCH_TIMER_VIRT_PPI])
> +             return ARCH_TIMER_VIRT_PPI;
>  
> -             if (!has_ppi) {
> -                     pr_warn("No interrupt available, giving up\n");
> -                     return -EINVAL;
> -             }
> -     }
> +     if (IS_ENABLED(CONFIG_ARM64))
> +             return ARCH_TIMER_PHYS_NONSECURE_PPI;
> +
> +     return ARCH_TIMER_PHYS_SECURE_PPI;

For a 32-bit platform booted at hyp (with a virt PPI available), the new
logic will select ARCH_TIMER_VIRT_PPI. I beleive that will break KVM.

I think the logic should be:

        if (is_kernel_in_hyp_mode())
                return ARCH_TIMER_HYP_PPI;

        if (!is_hyp_mode_available() &&
            arch_timer_ppi[ARCH_TIMER_VIRT_PPI])
                return ARCH_TIMER_VIRT_PPI;
        
        if (IS_ENABLED(CONFIG_ARM64))
                return ARCH_TIMER_PHYS_NONSECURE_PPI;
        
        return ARCH_TIMER_PHYS_SECURE_PPI;

Please use that instead (keeping the comment you retained).

> +static int __init arch_timer_init(void)
> +{
> +     int ret;
>  
>       ret = arch_timer_register();
>       if (ret)
> @@ -904,6 +906,13 @@ static int __init arch_timer_of_init(struct device_node 
> *np)
>       if (IS_ENABLED(CONFIG_ARM) &&
>           of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
>               arch_timer_uses_ppi = ARCH_TIMER_PHYS_SECURE_PPI;
> +     else
> +             arch_timer_uses_ppi = arch_timer_select_ppi();
> +
> +     if (!arch_timer_ppi[arch_timer_uses_ppi]) {
> +             pr_err("No interrupt available, giving up\n");
> +             return -EINVAL;
> +     }
>  
>       /* On some systems, the counter stops ticking when in suspend. */
>       arch_counter_suspend_stop = of_property_read_bool(np,
> @@ -1049,6 +1058,12 @@ static int __init arch_timer_acpi_init(struct 
> acpi_table_header *table)
>       /* Get the frequency from CNTFRQ */
>       arch_timer_detect_rate(NULL, NULL);
>  
> +     arch_timer_uses_ppi = arch_timer_select_ppi();
> +     if (!arch_timer_ppi[arch_timer_uses_ppi]) {
> +             pr_err("No interrupt available, giving up\n");
> +             return -EINVAL;
> +     }

I see that we have to duplicate this so we can special-case the
DT-specific behaviour, so that's fine by me.

If you can fix the arch_timer_select_ppi() logic as above, this should
be fine.

Thanks,
Mark.

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