Re: [PATCH v9 07/18] x86/virt/tdx: Do TDX module per-cpu initialization

Dave Hansen
2023-02-13T22:43:24Z

On 2/13/23 13:19, Huang, Kai wrote:
>> On 2/13/23 03:59, Kai Huang wrote:
>>> To avoid duplicated code, add a
>>> helper to call SEAMCALL on all online cpus one by one but with a skip
>>> function to check whether to skip certain cpus, and use that helper to
>>> do the per-cpu initialization.
>> ...
>>> +/*
>>> + * Call @func on all online cpus one by one but skip those cpus
>>> + * when @skip_func is valid and returns true for them.
>>> + */
>>> +static int tdx_on_each_cpu_cond(int (*func)(void *), void *func_data,
>>> + bool (*skip_func)(int cpu, void *),
>>> + void *skip_data)
>> I only see one caller of this. Where is the duplicated code?
> The other caller is in patch 15 (x86/virt/tdx: Configure global KeyID on all packages).
>
> I kinda mentioned this in the changelog:
>
> " Similar to the per-cpu module initialization, a later step to config the key for the global KeyID..."
>
> If we don't have this helper, then we can end up with having below loop in two functions:
>
> for_each_online(cpu) {
> if (should_skip(cpu))
> continue;
>
> // call @func on @cpu.
> }

I don't think saving two lines of actual code is worth the opacity that
results from this abstraction.