When installing a distro via EFI HTTP boot some OS installers expect the .iso image to be preserved and treat it as a "CDROM" to install packages.
This is problematic in EFI, since U-Boot mounts the image, starts the installer, and eventually calls ExitBootServices. At that point the image U-Boot mounted disappears. Some distros don't care and download the missing packages from a web archive, while others halt the installation complaining they can't find certain packages. If the firmware uses ACPI, this is supported by using NFIT which provides NVDIMM ramdisks to the OS and preserves the image. We don't have anything in place for Device Trees though. Since DT supports persistent memory nodes (pmem) use those and preserve the .iso for installers. The issue can be reproduced by attempting an EFI HTTP boot with Ubuntu live server ISO, or a Rocky Linux ISO. The installation would fail with the failure to locate certain packages. The patches are adding support for adding the pmem node to the DT that is being passed to the OS, along with removing the memory region containing the ISO image from the EFI memory map. This is being done through a helper function in the blkmap driver which scans for all blkmap mappings and does the above configurations for the relevant mappings. Changes since V5: * Move the failure message to the callback function instead of printing it in blkmap_get_preserved_pmem_slice() * Move the check for the callback function before entering the loop in blkmap_get_preserved_pmem_slice() * Return the error code returned by the callback function in blkmap_get_preserved_pmem_slice() Ilias Apalodimas (2): efi_loader: add a function to remove memory from the EFI map efi_loader: preserve installer images in pmem Masahisa Kojima (1): fdt: add support for adding pmem nodes Sughosh Ganu (3): blkmap: store type of blkmap slice in corresponding structure blkmap: add an attribute to preserve the mem mapping blkmap: pass information on ISO image to the OS boot/fdt_support.c | 41 +++++++++++++++++++++- boot/image-fdt.c | 7 ++++ cmd/blkmap.c | 9 +++-- drivers/block/blkmap.c | 65 ++++++++++++++++++++++++++++++++--- drivers/block/blkmap_helper.c | 2 +- include/blkmap.h | 21 ++++++++++- include/efi.h | 13 +++++++ include/efi_loader.h | 18 ++++++++++ include/fdt_support.h | 14 ++++++++ lib/efi_loader/efi_bootmgr.c | 22 +++++++++--- lib/efi_loader/efi_helper.c | 40 +++++++++++++++++++++ lib/efi_loader/efi_memory.c | 56 +++++++++++++++++++++--------- 12 files changed, 278 insertions(+), 30 deletions(-) -- 2.34.1
