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Trammell Hudson
8a71d50ed4
This patch adds support for bundling the xen.efi hypervisor, the xen.cfg configuration file, the Linux kernel and initrd, as well as the XSM, and architectural specific files into a single "unified" EFI executable. This allows an administrator to update the components independently without requiring rebuilding xen, as well as to replace the components in an existing image. The resulting EFI executable can be invoked directly from the UEFI Boot Manager, removing the need to use a separate loader like grub as well as removing dependencies on local filesystem access. And since it is a single file, it can be signed and validated by UEFI Secure Boot without requring the shim protocol. It is inspired by systemd-boot's unified kernel technique and borrows the function to locate PE sections from systemd's LGPL'ed code. During EFI boot, Xen looks at its own loaded image to locate the PE sections for the Xen configuration (`.config`), dom0 kernel (`.kernel`), dom0 initrd (`.ramdisk`), and XSM config (`.xsm`), which are included after building xen.efi using objcopy to add named sections for each input file. For x86, the CPU ucode can be included in a section named `.ucode`, which is loaded in the efi_arch_cfg_file_late() stage of the boot process. On ARM systems the Device Tree can be included in a section named `.dtb`, which is loaded during the efi_arch_cfg_file_early() stage of the boot process. Note that the system will fall back to loading files from disk if the named sections do not exist. This allows distributions to continue with the status quo if they want a signed kernel + config, while still allowing a user provided initrd (which is how the shim protocol currently works as well). This patch also adds constness to the section parameter of efi_arch_cfg_file_early() and efi_arch_cfg_file_late(), changes pe_find_section() to use a const CHAR16 section name, and adds pe_name_compare() to match section names. Signed-off-by: Trammell Hudson <hudson@trmm.net> Reviewed-by: Jan Beulich <jbeulich@suse.com> [Fix ARM build by including pe.init.o] Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
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