Re: [Xen-devel] [PATCH] xen/arm: correct flush_tlb_mask behaviour

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Thu, 2014-01-09 at 16:58 +0000, Julien Grall wrote:
> On ARM, flush_tlb_mask is used in the common code:
>     - alloc_heap_pages: the flush is only be called if the new allocated
>     page was used by a domain before. So we need to flush only TLB non-secure
> non-hyp inner-shareable.
>     - common/grant-table.c: every calls to flush_tlb_mask are used with
>     the current domain. A flush TLB by current VMID inner-shareable is enough.
> 
> The current code only flush hypervisor TLB on the current PCPU. For now,
> flush TLBs non-secure non-hyp on every PCPUs.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>

Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

> ---
>     This patch is bug fix for Xen 4.4. We were safe because there is already
> a flush in create_p2m_entries if the previous mapping was valid.
> 
> For Xen 4.5, we should optimize the function to avoid flush for every VMIDs
> each time we allocated a new page.

Right, this whole are is ripe for rationalisation and optimisation.

Ian.


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