On 12/03/19 at 12:45am, Michael Weiser wrote: > Hi Dave, > > On Mon, Dec 02, 2019 at 05:05:20PM +0800, Dave Young wrote: > > > > It seems a serious problem, the EFI modified memmap does not get an > > > /proc/iomem resource update, but kexec_file relies on /proc/iomem in > > > X86. > > > > > > There is an question from Sai about why add_efi_memmap is not enabled by > > > default: > > > https://www.spinics.net/lists/linux-mm/msg185166.html > > Incidentally, a data point I did not think to mention: I do boot the > kernel as EFI application directly from the firmware as a boot entry > with compiled in initrd and command line: > > $ grep EFI nobak/kernel/linux/.config > CONFIG_EFI=y > CONFIG_EFI_STUB=y > # CONFIG_EFI_MIXED is not set > CONFIG_DMI_SCAN_MACHINE_NON_EFI_FALLBACK=y > # EFI (Extensible Firmware Interface) Support > CONFIG_EFI_VARS=m > CONFIG_EFI_ESRT=y > CONFIG_EFI_VARS_PSTORE=m > # CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE is not set > CONFIG_EFI_RUNTIME_MAP=y > # CONFIG_EFI_FAKE_MEMMAP is not set > CONFIG_EFI_RUNTIME_WRAPPERS=y > # CONFIG_EFI_BOOTLOADER_CONTROL is not set > # CONFIG_EFI_CAPSULE_LOADER is not set > # CONFIG_EFI_TEST is not set > # CONFIG_EFI_RCI2_TABLE is not set > # end of EFI (Extensible Firmware Interface) Support > CONFIG_UEFI_CPER=y > CONFIG_UEFI_CPER_X86=y > CONFIG_EFI_EARLYCON=y > CONFIG_EFI_PARTITION=y > CONFIG_FB_EFI=y > CONFIG_EFIVAR_FS=y > # CONFIG_EFI_PGT_DUMP is not set > > $ grep CMDLINE nobak/kernel/linux/.config > CONFIG_CMDLINE_BOOL=y > CONFIG_CMDLINE="root=UUID=97[...]e4 rd.luks.uuid=8a[...]c3 rd.luks.allow-discards=8a[...]c3 mem_sleep_default=deep resume=UUID=97[...]e4 resume_offset=96256 efi=debug memblock=debug" > CONFIG_CMDLINE_OVERRIDE=y > # CONFIG_BLK_CMDLINE_PARSER is not set > # CONFIG_CMDLINE_PARTITION is not set > CONFIG_FB_CMDLINE=y > > $ efibootmgr -v > BootCurrent: 000A > Timeout: 2 seconds > BootOrder: 000A,0009,0008,0005,0007,0006,0004,0002,0001,0000,0003 > [...] > Boot0005* gentoo-5.4.0-next-20191127+-clear > HD(1,GPT,e7[...]f2,0x800,0x64000)/File(\kernel-5.4.0-next-20191127+-clear) > [...] > Boot000A* gentoo-5.4.1-gentoo > HD(1,GPT,e7[...]f2,0x800,0x64000)/File(\kernel-5.4.1-gentoo) > > So there's no boot loader that could construct an e820 table for the > kernel to consume. I understand it's then up to the EFI stub to come up > with a e820 table from the EFI memory map. > > > > Long time ago the add_efi_memmap is only enabled in case we explict > > > enable it on cmdline, I'm not sure if we can do it by default, maybe we > > > should. Need opinion from X86 maintainers.. > > > Can you try below diff see if it works for you? (not tested, and need > > > explicitly 'add_efi_memmap' in kernel cmdline param) > > Neither adding add_efi_memmap nor adding your patch and setting that option > does make the ESRT memory region appear in /proc/iomem. kexec_file still > loads the kernel across the ESRT region. > Hmm, sorry, my bad, actuall add_efi_memmap does not consider the EFI_MEMORY_RUNTIME attribute, it only reads the memory descriptor types. Will read your replied information later, did not get time today, but probably below chunk can help? diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c index 3b9fd679cea9..516307617621 100644 --- a/arch/x86/platform/efi/quirks.c +++ b/arch/x86/platform/efi/quirks.c @@ -293,6 +293,8 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size) early_memunmap(new, new_size); efi_memmap_install(new_phys, num_entries); + e820__range_update(addr, size, E820_TYPE_RAM, E820_TYPE_RESERVED); + e820__update_table(e820_table); } /* Thanks Dave
