Re: [PATCH v3 19/19] xen/arm: mm: Re-implement setup_frame_table_mappings() with map_pages_to_xen()

[Julien Grall <julien@xen.org>]

Hi Stefano,

On 06/04/2022 01:01, Stefano Stabellini wrote:
> On Mon, 21 Feb 2022, Julien Grall wrote:
>>       frametable_base_pdx = mfn_to_pdx(maddr_to_mfn(ps));
>>       /* Round up to 2M or 32M boundary, as appropriate. */
>>       frametable_size = ROUNDUP(frametable_size, mapping_size);
>>       base_mfn = alloc_boot_pages(frametable_size >> PAGE_SHIFT, 32<<(20-12));
>>   
>> -#ifdef CONFIG_ARM_64
>> -    /* Compute the number of second level pages. */
>> -    nr_second = ROUNDUP(frametable_size, FIRST_SIZE) >> FIRST_SHIFT;
>> -    second_base = alloc_boot_pages(nr_second, 1);
>> -    second = mfn_to_virt(second_base);
>> -    for ( i = 0; i < nr_second; i++ )
>> -    {
>> -        clear_page(mfn_to_virt(mfn_add(second_base, i)));
>> -        pte = mfn_to_xen_entry(mfn_add(second_base, i), MT_NORMAL);
>> -        pte.pt.table = 1;
>> -        write_pte(&xen_first[first_table_offset(FRAMETABLE_VIRT_START)+i], pte);
>> -    }
>> -    create_mappings(second, 0, mfn_x(base_mfn), frametable_size >> PAGE_SHIFT,
>> -                    mapping_size);
>> -#else
>> -    create_mappings(xen_second, FRAMETABLE_VIRT_START, mfn_x(base_mfn),
>> -                    frametable_size >> PAGE_SHIFT, mapping_size);
>> -#endif
>> +    rc = map_pages_to_xen(FRAMETABLE_VIRT_START, base_mfn,
>> +                          frametable_size >> PAGE_SHIFT, PAGE_HYPERVISOR_RW);
> 
> Doesn't it need to be PAGE_HYPERVISOR_RW | _PAGE_BLOCK ?

You are right. Otherwise, it would only use small pages. I will fix it 
in the next version.

Cheers,

-- 
Julien Grall