Re: [PATCH 4/6] x86/smpboot: map and unmap page tables in cleanup_cpu_root_pgt

[Julien Grall <julien@xxxxxxx>]

Hi,

On 17/04/2020 10:52, Hongyan Xia wrote:
> From: Wei Liu <wei.liu2@xxxxxxxxxx>
>
> Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> Signed-off-by: Hongyan Xia <hongyxia@xxxxxxxxxx>
Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>

> ---
>   xen/arch/x86/smpboot.c | 25 +++++++++++++++++--------
>   1 file changed, 17 insertions(+), 8 deletions(-)
>
> diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
> index 09264b02d1..275ce7661d 100644
> --- a/xen/arch/x86/smpboot.c
> +++ b/xen/arch/x86/smpboot.c
> @@ -858,23 +858,27 @@ static void cleanup_cpu_root_pgt(unsigned int cpu)
>             r < root_table_offset(HYPERVISOR_VIRT_END); ++r )
>       {
>           l3_pgentry_t *l3t;
> +        mfn_t l3mfn;
>           unsigned int i3;
>   
>           if ( !(root_get_flags(rpt[r]) & _PAGE_PRESENT) )
>               continue;
>   
> -        l3t = l4e_to_l3e(rpt[r]);
> +        l3mfn = l4e_get_mfn(rpt[r]);
> +        l3t = map_domain_page(l3mfn);
>   
>           for ( i3 = 0; i3 < L3_PAGETABLE_ENTRIES; ++i3 )
>           {
>               l2_pgentry_t *l2t;
> +            mfn_t l2mfn;
>               unsigned int i2;
>   
>               if ( !(l3e_get_flags(l3t[i3]) & _PAGE_PRESENT) )
>                   continue;
>   
>               ASSERT(!(l3e_get_flags(l3t[i3]) & _PAGE_PSE));
> -            l2t = l3e_to_l2e(l3t[i3]);
> +            l2mfn = l3e_get_mfn(l3t[i3]);
> +            l2t = map_domain_page(l2mfn);
>   
>               for ( i2 = 0; i2 < L2_PAGETABLE_ENTRIES; ++i2 )
>               {
> @@ -882,13 +886,15 @@ static void cleanup_cpu_root_pgt(unsigned int cpu)
>                       continue;
>   
>                   ASSERT(!(l2e_get_flags(l2t[i2]) & _PAGE_PSE));
> -                free_xen_pagetable(l2e_to_l1e(l2t[i2]));
> +                free_xen_pagetable_new(l2e_get_mfn(l2t[i2]));
>               }
>   
> -            free_xen_pagetable(l2t);
> +            unmap_domain_page(l2t);
> +            free_xen_pagetable_new(l2mfn);
>           }
>   
> -        free_xen_pagetable(l3t);
> +        unmap_domain_page(l3t);
> +        free_xen_pagetable_new(l3mfn);
>       }
>   
>       free_xen_pagetable(rpt);
> @@ -896,11 +902,14 @@ static void cleanup_cpu_root_pgt(unsigned int cpu)
>       /* Also zap the stub mapping for this CPU. */
>       if ( stub_linear )
>       {
> -        l3_pgentry_t *l3t = l4e_to_l3e(common_pgt);
> -        l2_pgentry_t *l2t = l3e_to_l2e(l3t[l3_table_offset(stub_linear)]);
> -        l1_pgentry_t *l1t = l2e_to_l1e(l2t[l2_table_offset(stub_linear)]);
> +        l3_pgentry_t l3e = l3e_from_l4e(common_pgt,
> +                                        l3_table_offset(stub_linear));
> +        l2_pgentry_t l2e = l2e_from_l3e(l3e, l2_table_offset(stub_linear));
> +        l1_pgentry_t *l1t = map_l1t_from_l2e(l2e);
>   
>           l1t[l1_table_offset(stub_linear)] = l1e_empty();
> +
> +        unmap_domain_page(l1t);
>       }
>   }
>   
Cheers,

--
Julien Grall