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Ping: [PATCH] x86/EPT: squash meaningless TLB flush


  • To: Kevin Tian <kevin.tian@xxxxxxxxx>, Jun Nakajima <jun.nakajima@xxxxxxxxx>
  • From: Jan Beulich <jbeulich@xxxxxxxx>
  • Date: Fri, 10 Dec 2021 10:32:23 +0100
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  • Cc: "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
  • Delivery-date: Fri, 10 Dec 2021 09:32:44 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On 30.11.2021 17:10, Jan Beulich wrote:
> ept_free_entry() gets called after a flush - if one is necessary in the
> first place - was already issued. That behavior is similar to NPT, which
> also doesn't have any further flush in p2m_free_entry(). (Furthermore,
> the function being recursive, in case of recursiveness way too many
> flushes would have been issued.)
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

May I ask for an ack or otherwise here? From all I can tell I have addressed
Andrew's comment.

Jan

> --- a/xen/arch/x86/mm/p2m-ept.c
> +++ b/xen/arch/x86/mm/p2m-ept.c
> @@ -246,8 +246,7 @@ static void ept_free_entry(struct p2m_do
>              ept_free_entry(p2m, epte + i, level - 1);
>          unmap_domain_page(epte);
>      }
> -    
> -    p2m_tlb_flush_sync(p2m);
> +
>      p2m_free_ptp(p2m, mfn_to_page(_mfn(ept_entry->mfn)));
>  }
>  




 


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