Hi Julien, On Mon, May 30, 2016 at 10:53:24PM +0100, Julien Grall wrote: >Hi Peng, > >On 27/05/2016 06:31, Peng Fan wrote: >>To ARM64, setup_xenheap_mappings may call alloc_boot_pages to allocate >>first level page table, if there is a big chunk memory (ie, >512GB). > >Out of interest, have you found the bug by testing Xen on a platform with >512GB of RAM? :)
Actually not. My board does not have so large memory. When I am reading the piece code, I think there is possibility that setup_xenheap_mappings may need boot pages, but boot pages are not ready. > >>So, need to make sure boot pages are ready before setup xenheap mappings. > >init_boot_pages is using mfn_to_virt (see bootmem_region_add), which cannot >work until xenheap_mfn_start is initialized. This is done by >setup_xenheap_mappings. My bad. I did not catch this point. Thanks for correcting me. > >I would be happy to give you hint on how to solve this, but I am not sure to >fully understand your issue. Can you give more details? I did not met issue on my platform. I just think the logic of this piece code may cause errors on platform with large memory (>512GB). How about the following patch? First loop all the memory banks and calculate ram_size/ram_start/ram_end, then set xenheap_virt_end/start and xenheap_mfn_end. Now readly for init boot pages and setup_xenheap_mappings. diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c index dcb23b7..d3a3af3 100644 --- a/xen/arch/arm/setup.c +++ b/xen/arch/arm/setup.c @@ -635,13 +635,24 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size) paddr_t bank_start = bootinfo.mem.bank[bank].start; paddr_t bank_size = bootinfo.mem.bank[bank].size; paddr_t bank_end = bank_start + bank_size; - paddr_t s, e; ram_size = ram_size + bank_size; ram_start = min(ram_start,bank_start); ram_end = max(ram_end,bank_end); + } - setup_xenheap_mappings(bank_start>>PAGE_SHIFT, bank_size>>PAGE_SHIFT); + total_pages += ram_size >> PAGE_SHIFT; + + xenheap_virt_end = XENHEAP_VIRT_START + ram_end - ram_start; + xenheap_mfn_start = ram_start >> PAGE_SHIFT; + xenheap_mfn_end = ram_end >> PAGE_SHIFT; + + for ( bank = 0 ; bank < bootinfo.mem.nr_banks; bank++ ) + { + paddr_t bank_start = bootinfo.mem.bank[bank].start; + paddr_t bank_size = bootinfo.mem.bank[bank].size; + paddr_t bank_end = bank_start + bank_size; + paddr_t s, e; s = bank_start; while ( s < bank_end ) @@ -658,18 +669,12 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size) if ( e > bank_end ) e = bank_end; - xenheap_mfn_end = e; - dt_unreserved_regions(s, e, init_boot_pages, 0); s = n; } - } - - total_pages += ram_size >> PAGE_SHIFT; - xenheap_virt_end = XENHEAP_VIRT_START + ram_end - ram_start; - xenheap_mfn_start = ram_start >> PAGE_SHIFT; - xenheap_mfn_end = ram_end >> PAGE_SHIFT; + setup_xenheap_mappings(bank_start>>PAGE_SHIFT, bank_size>>PAGE_SHIFT); + } /* * Need enough mapped pages for copying the DTB. Thanks, Peng. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel