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References: <1458222382-6498-1-git-send-email-sergey.fedorov@linaro.org>
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From: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <56EAC8A2.7060700@redhat.com>
Date: Thu, 17 Mar 2016 16:09:22 +0100
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Subject: Re: [Qemu-devel] [PATCH 4/5] tcg: reorder removal from lists in
	tb_phys_invalidate
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To: sergey.fedorov@linaro.org, qemu-devel@nongnu.org
Cc: Sergey Fedorov <serge.fdrv@gmail.com>, Richard Henderson <rth@twiddle.net>, Peter Crosthwaite <crosthwaite.peter@gmail.com>



On 17/03/2016 14:46, sergey.fedorov@linaro.org wrote:
>  void tb_phys_invalidate(TranslationBlock *tb, tb_page_addr_t page_addr=
)
>  {
> -    CPUState *cpu;
>      PageDesc *p;
>      unsigned int h, n1;
> +    tb_page_addr_t pc;
>      tb_page_addr_t phys_pc;
>      TranslationBlock *tb1, *tb2;
> =20
> -    /* remove the TB from the hash list */
> -    phys_pc =3D tb->page_addr[0] + (tb->pc & ~TARGET_PAGE_MASK);
> -    h =3D tb_phys_hash_func(phys_pc);
> -    tb_hash_remove(&tcg_ctx.tb_ctx.tb_phys_hash[h], tb);
> -
> -    /* remove the TB from the page list */
> -    if (tb->page_addr[0] !=3D page_addr) {
> -        p =3D page_find(tb->page_addr[0] >> TARGET_PAGE_BITS);
> -        tb_page_remove(&p->first_tb, tb);
> -        invalidate_page_bitmap(p);
> -    }
> -    if (tb->page_addr[1] !=3D -1 && tb->page_addr[1] !=3D page_addr) {
> -        p =3D page_find(tb->page_addr[1] >> TARGET_PAGE_BITS);
> -        tb_page_remove(&p->first_tb, tb);
> -        invalidate_page_bitmap(p);
> -    }
> -
> -    tcg_ctx.tb_ctx.tb_invalidated_flag =3D 1;
> -

Did you investigate the removal of this setting of tb_invalidated_flag?

My recollection is that it is okay to remove it because at worse it
would cause a tb_add_jump from an invalidated source to a valid
destination.  This should be harmless as long as the source has been
tb_phys_invalidated and not tb_flushed.  But this needs to be checked.

Paolo