Re: [PATCH RFC 5/6] xen/arm: mm: Don't open-code Xen PT update in remove_early_mappings

[Stefano Stabellini <sstabellini@kernel.org>]

On Thu, 19 Nov 2020, Julien Grall wrote:
> From: Julien Grall <julien.grall@arm.com>
> 
> Now that xen_pt_update_entry() is able to deal with different mapping
> size, we can replace the open-coding of the page-tables update by a call
> to modify_xen_mappings().
> 
> As the function is not meant to fail, a BUG_ON is added to check the
> return.
> 
> Signed-off-by: Julien Grall <julien.grall@arm.com>
> Signed-off-by: Julien Grall <julien.grall@amazon.com>

Acked-by: Stefano Stabellini <sstabellini@kernel.org>


> ---
>  xen/arch/arm/mm.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> index af0f12b6e6d3..aee6d410ac4f 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -598,11 +598,11 @@ void * __init early_fdt_map(paddr_t fdt_paddr)
>  
>  void __init remove_early_mappings(void)
>  {
> -    lpae_t pte = {0};
> -    write_pte(xen_second + second_table_offset(BOOT_FDT_VIRT_START), pte);
> -    write_pte(xen_second + second_table_offset(BOOT_FDT_VIRT_START + SZ_2M),
> -              pte);
> -    flush_xen_tlb_range_va(BOOT_FDT_VIRT_START, BOOT_FDT_SLOT_SIZE);
> +    int rc;
> +
> +    rc = modify_xen_mappings(BOOT_FDT_VIRT_START, BOOT_FDT_VIRT_END,
> +                             _PAGE_BLOCK);
> +    BUG_ON(rc);
>  }
>  
>  /*
> -- 
> 2.17.1
>