Re: [PATCH 2/5] x86_64/mm: map and unmap page tables in m2p_mapped

[Jan Beulich <jbeulich@xxxxxxxx>]

On 23.03.2020 10:41, Hongyan Xia wrote:
> --- a/xen/arch/x86/x86_64/mm.c
> +++ b/xen/arch/x86/x86_64/mm.c
> @@ -131,27 +131,33 @@ static int m2p_mapped(unsigned long spfn)
>      unsigned long va;
>      l3_pgentry_t *l3_ro_mpt;
>      l2_pgentry_t *l2_ro_mpt;
> +    int rc = M2P_NO_MAPPED;
>  
>      va = RO_MPT_VIRT_START + spfn * sizeof(*machine_to_phys_mapping);
> -    l3_ro_mpt = l4e_to_l3e(idle_pg_table[l4_table_offset(va)]);
> +    l3_ro_mpt = map_l3t_from_l4e(idle_pg_table[l4_table_offset(va)]);

Along the lines of what I've said for patch 1 - read the l3e
here and unmap again right away. No need for converting
"return" to "goto" further down. Same for the l2e then.

Jan