On Mon, Aug 05, 2013 at 11:26:46PM +0200, Laszlo Ersek wrote: > What happens if you pass "memblock=debug" on the kernel command line > (see early_memblock() in "mm/memblock.c")? > > (I just tried it in my Fedora 19 guest, and it in fact produced the message > > [ 0.000000] efi: Could not reserve boot range [0x0000800000-0x0000ffffff] Note to self: Always look for bugs in Linux' UEFI code first, before going anywhere else! Yes, very good analysis and good job Laszlo! I'll write what I see now but will doublecheck it tomorrow because I'm almost half asleep. [ 0.000000] efi: efi_reserve_boot_services: -> start: 0x7e0ad000, size: 0x1f000 [ 0.000000] efi: Could not reserve boot range [0x007e0ad000-0x007e0cbfff] And yes, this fails because memblock_is_region_reserved(start, size) returns true. And why is that: [ 0.000000] memblock_reserve: [0x000000036be000-0x000000036c3000] setup_arch+0x60e/0xa63 [ 0.000000] MEMBLOCK configuration: [ 0.000000] memory size = 0x7fef1000 reserved size = 0x1724570 [ 0.000000] memory.cnt = 0x4 [ 0.000000] memory[0x0] [0x00000000001000-0x0000000009ffff], 0x9f000 bytes [ 0.000000] memory[0x1] [0x00000000100000-0x0000007e667fff], 0x7e568000 bytes [ 0.000000] memory[0x2] [0x0000007e692000-0x0000007fb11fff], 0x1480000 bytes [ 0.000000] memory[0x3] [0x0000007fb76000-0x0000007ffdffff], 0x46a000 bytes [ 0.000000] reserved.cnt = 0x3 [ 0.000000] reserved[0x0] [0x0000000009f000-0x000000000fffff], 0x61000 bytes [ 0.000000] reserved[0x1] [0x00000002000000-0x000000036c2fff], 0x16c3000 bytes [ 0.000000] reserved[0x2] [0x0000007e0ad018-0x0000007e0ad587], 0x570 bytes ^^^^^^^^^ There are 0x570 bytes right in this region which are memblock-reserved and so we truncate it in efi_reserve_boot_services(). This makes me say words which will offend this list so I'll instead go out on the balcony and wake up the neighbors. :-) Ok, thanks again for finding it, I'll go and try to figure out the whole mess tomorrow. Good night! > BTW, regarding Michael's answer, I think this is just one of several > ways in which Linux manipulates the EFI memmap between (b) and (c). > For example it seems to merge ranges in the map. Yes, it does so in efi_enter_virtual_mode(). That was my initial suspicion, that's why I dumped the regions before the merging. Thanks. -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html