On Fri, 28 Jul, at 07:26:03PM, Baoquan He wrote: > Hi Matt, > > On 07/28/17 at 11:55am, Ingo Molnar wrote: > > > > * Matt Fleming <m...@codeblueprint.co.uk> wrote: > > > > > On Fri, 21 Jul, at 09:19:56PM, Baoquan He wrote: > > > > > > > > There are places where the efi map is getting and used like this. E.g > > > > in efi_high_alloc() of drivers/firmware/efi/libstub/efi-stub-helper.c. > > > > EFI developers worry the size of efi_memory_desc_t could not be the same > > > > as e->efi_memdesc_size? > > > > > > > > Hi Matt, > > > > > > > > Could you help have a look at this? > > > > > > You're exactly right. The code guards against the size of the > > > efi_memory_desc_t struct changing. The UEFI spec says to traverse the > > > memory map this way. > > > > This is not obvious and looks pretty ugly as well, and open coded in > > several > > places. > > > > At minimum we should have an efi_memdesc_ptr(efi, i) wrapper inline (or so) > > that > > gives us the entry pointer, plus a comment that points out that > > ->memdesc_size > > might not be equal to sizeof(efi_memory_memdesc_t). > > I can make a efi_memdesc_ptr(efi, i) wrapper as Ingo suggested and use > it here if you agree. Seems it might be not good to add another > for_each_efi_memory_desc_xxxx wrapper since there are different memmap > data structures in x86 boot and in general efi libstub. Or any other > idea?
I think adding a wrapper is fine, but I'd suggest including the word "early" (or something similar) to explain that it should only be used during bootup -- we want everyone else to use the for_each_efi_memory_*() API.
