Il 15/08/2013 09:59, Arthur Chunqi Li ha scritto:
>> > volatile u32 stage? And we have barrier() to avoid reordering.
> Reordering here is not a big deal here, though it is actually needed
> here. I occurred the following problem:
>
> stage = 1;
> do something that causes vmexit;
> stage = 2;
>
> Then the compiler will optimize "stage = 1" and "stage = 2" to one
> instruction "stage =2", since instructions between them don't use
> "stage". Can volatile solve this problem?
I'm not sure if volatile stores are reordered against non-volatile stores.
Better keep set_stage() but write it as
barrier();
stage = s;
barrier();
Paolo
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