Re: [Qemu-devel] [PATCH 4/5] tcg: reorder removal from lists in tb_phys_invalidate

[Sergey Fedorov]

On 17/03/16 16:46, address@hidden wrote:
> First the translation block is invalidated, for which a simple write
> to tb->pc is enough.  This means that cpu-exec will not pick up anymore
> the block, though it may still execute it through chained jumps.  This
> also replaces the NULLing out of the pointer in the CPUs' local cache.

Although, using 'tb->pc' to mark a TB as invalid is probably not such a
good idea. There may be some cases when PC could become equal to -1. For
example, ARMv6-M uses PC >= 0xFFFFFFF0 to perform exception return. So
we'd better introduce a separate 'tb->valid' or 'tb->invalid' flag.

Kind regards,
Sergey