Hi Heinrich, On Fri, 7 Jul 2023 at 15:34, Heinrich Schuchardt <xypron.g...@gmx.de> wrote: > > On 7/7/23 06:00, Masahisa Kojima wrote: > > This series introduces the EFI_RAM_DISK_PROTOCOL implementation. > > The major purpose of this series is a preparation for EFI HTTP(S) boot. > > > > Now U-Boot can download the distro installer ISO image > > via wget or tftpboot commands, but U-Boot can not mount > > the downloaded ISO image. > > By calling EFI_RAM_DISK_PROTOCOL->register API, user can > > mount the ISO image and boot the distro installer. > > If I understand you correctly, with your design RAM disks will only > exist in the EFI sub-system.
Yes, RAM disk can be accessed through the EFI sub-system. > > We strive to synchronize what is happening on the driver model level and > on the UEFI level. I would prefer a design where we have a UCLASS_BLK > driver ram disks and the EFI_RAM_DISK_PROTOCOL is a one method of > managing ram disk devices. The current EFI_RAM_DIISK_PROTOCOL implementation is the same as what EDK2 reference implementation does, and I'm not yet fully convinced how much the native U-Boot gets the benefit of RAM disk support. > > A big issue we have is RAM management. malloc() can only assign limited > amount of memory which is probably too small for the RAM disk you are > looking at. We manage page sized memory in the EFI sub-system but this > is not integrated with the LMB memory checks. OK, when we think about EFI HTTP boot and hand-off the RAM disk to the kernel, we need to consider the memory allocation for the big ISO image. But as far as EFI_RAM_DISK_PROTOCOL is concerned, can we leave the memory management issue? Thanks, Masahisa Kojima > > The necessary sequence of development is probably: > > * Rework memory management > * Implement ramdisks as UCLASS_BLK driver > * Implement the EFI_RAM_DISK_PROTOCOL based on the UCLASS_BLK driver. > > Best regards > > Heinrich > > > > > Note that the installation process may not proceed > > after the distro installer calls ExitBootServices() > > since there is no hand-off process for the block device of > > memory mapped ISO image. > > > > The EFI_RAM_DISK_PROTOCOL was tested with the > > debian network installer[1] on qemu_arm64 platform. > > The example procedure is as follows. > > => tftpboot 41000000 mini.iso > > => efidebug disk load 41000000 $filesize > > > > After these commands, ISO image is mounted like: > > > > => efidebug dh > > > > 000000007eec5910 (efiblk#0) > > > > /RamDisk(0x41000000,4974afff,3d5abd30-4175-87ce-6d64-d2ade523c4bb,0x0) > > Block IO > > > > 000000007eec6140 (efiblk#0:1) > > > > /RamDisk(0x41000000,4974afff,3d5abd30-4175-87ce-6d64-d2ade523c4bb,0x0)/HD(1,0x01,0,0x0,0x33800) > > Block IO > > > > 000000007eec62b0 (efiblk#0:2) > > > > /RamDisk(0x41000000,4974afff,3d5abd30-4175-87ce-6d64-d2ade523c4bb,0x0)/HD(2,0x01,0,0x33800,0x10000) > > Block IO > > System Partition > > Simple File System > > > > => dm tree > > > > blk 0 [ + ] efi_blk `-- efiblk#0 > > partition 0 [ + ] blk_partition |-- efiblk#0:1 > > partition 1 [ + ] blk_partition `-- efiblk#0:2 > > > > Debian can be successfully installed with this RAM disk on QEMU. > > > > [TODO] > > - udevices created in ./lib/efi_driver/efi_block_device.c::efi_bl_bind() > > are not removed when the efi_handle is removed. > > So after unload the RAM disk, udevices still exist. > > I plan to add a udevice removal process in > > ./lib/efi_driver/efi_uclass.c::efi_uc_stop(). > > In addition, I also plan to add unbind() callback in struct > > efi_driver_ops. > > > > > > [1] > > https://deb.debian.org/debian/dists/bookworm/main/installer-arm64/current/images/netboot/mini.iso > > > > Masahisa Kojima (4): > > efi_loader: add RAM disk device path > > efi_loader: add EFI_RAM_DISK_PROTOCOL implementation > > cmd: efidebug: add RAM disk mount command > > efi_selftest: add EFI_RAM_DISK_PROTOCOL selftest > > > > cmd/efidebug.c | 117 ++++++ > > include/efi_api.h | 32 ++ > > include/efi_loader.h | 4 + > > lib/efi_driver/efi_uclass.c | 7 +- > > lib/efi_loader/Kconfig | 6 + > > lib/efi_loader/Makefile | 1 + > > lib/efi_loader/efi_device_path_to_text.c | 14 + > > lib/efi_loader/efi_ram_disk.c | 334 +++++++++++++++ > > lib/efi_loader/efi_setup.c | 6 + > > lib/efi_selftest/Makefile | 1 + > > lib/efi_selftest/efi_selftest_ram_disk.c | 511 +++++++++++++++++++++++ > > lib/uuid.c | 4 + > > 12 files changed, 1035 insertions(+), 2 deletions(-) > > create mode 100644 lib/efi_loader/efi_ram_disk.c > > create mode 100644 lib/efi_selftest/efi_selftest_ram_disk.c > > > > > > base-commit: e2e2aea5733f0d23cd9593bbefe5c803c552dcb9 >
