Re: [Xen-devel] [PATCH RFC 25/55] x86_64/mm: introduce pl2e in setup_m2p_table

["Nuernberger, Stefan" <snu@xxxxxxxxx>]

On Thu, 2019-02-07 at 16:44 +0000, Wei Liu wrote:
> Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> ---
>  xen/arch/x86/x86_64/mm.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
> index 55fa338d71..d3e2398b6c 100644
> --- a/xen/arch/x86/x86_64/mm.c
> +++ b/xen/arch/x86/x86_64/mm.c
> @@ -397,7 +397,7 @@ static int setup_m2p_table(struct mem_hotadd_info
> *info)
>  {
>      unsigned long i, va, smap, emap;
>      unsigned int n;
> -    l2_pgentry_t *l2_ro_mpt = NULL;
> +    l2_pgentry_t *pl2e = NULL, *l2_ro_mpt;

nit: Here too, the next patch will add the NULL initialization back in.

>      l3_pgentry_t *l3_ro_mpt = NULL;
>      int ret = 0;
>  
> @@ -458,7 +458,7 @@ static int setup_m2p_table(struct mem_hotadd_info
> *info)
>                    _PAGE_PSE));
>              if ( l3e_get_flags(l3_ro_mpt[l3_table_offset(va)]) &
>                _PAGE_PRESENT )
> -                l2_ro_mpt =
> l3e_to_l2e(l3_ro_mpt[l3_table_offset(va)]) +
> +                pl2e = l3e_to_l2e(l3_ro_mpt[l3_table_offset(va)]) +
>                    l2_table_offset(va);
>              else
>              {
> @@ -473,11 +473,12 @@ static int setup_m2p_table(struct
> mem_hotadd_info *info)
>                  l3e_write(&l3_ro_mpt[l3_table_offset(va)],
>                            l3e_from_paddr(__pa(l2_ro_mpt),
>                                           __PAGE_HYPERVISOR_RO |
> _PAGE_USER));
> -                l2_ro_mpt += l2_table_offset(va);
> +                pl2e = l2_ro_mpt;
> +                pl2e += l2_table_offset(va);

nit: These could also be on a single line.

- Stefan

>              }
>  
>              /* NB. Cannot be GLOBAL: guest user mode should not see
> it. */
> -            l2e_write(l2_ro_mpt, l2e_from_mfn(mfn,
> +            l2e_write(pl2e, l2e_from_mfn(mfn,
>                     /*_PAGE_GLOBAL|*/_PAGE_PSE|_PAGE_USER|_PAGE_PRESE
> NT));
>          }
>          i += ( 1UL << (L2_PAGETABLE_SHIFT - 3));



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