On Tue, Jul 8, 2025 at 9:02 PM Frediano Ziglio via Grub-devel
<grub-devel@gnu.org> wrote:
>
> Allows to load modules using LoadFile2 protocol.
> Add and use a new GUID for kernel media device.
> This will allow Xen to pick up additional modules using
> EFI interface instead of using multiboot2 interface (not
> available on x86_64).
>
> Signed-off-by: Frediano Ziglio <frediano.zig...@cloud.com>
> ---
> grub-core/loader/arm64/xen_boot.c | 172 +++++++++++++++++++++++++++++-
> include/grub/efi/api.h | 5 +
> 2 files changed, 176 insertions(+), 1 deletion(-)
>
> diff --git a/grub-core/loader/arm64/xen_boot.c
> b/grub-core/loader/arm64/xen_boot.c
> index 2975a546e..64f685de6 100644
> --- a/grub-core/loader/arm64/xen_boot.c
> +++ b/grub-core/loader/arm64/xen_boot.c
> @@ -68,6 +68,56 @@ enum module_type
> };
> typedef enum module_type module_type_t;
>
> +static grub_guid_t load_file2_guid = GRUB_EFI_LOAD_FILE2_PROTOCOL_GUID;
> +static grub_guid_t device_path_guid = GRUB_EFI_DEVICE_PATH_GUID;
> +
> +static initrd_media_device_path_t initrd_lf2_device_path = {
> + {
> + {
> + GRUB_EFI_MEDIA_DEVICE_PATH_TYPE,
> + GRUB_EFI_VENDOR_MEDIA_DEVICE_PATH_SUBTYPE,
> + sizeof(grub_efi_vendor_media_device_path_t),
> + },
> + LINUX_EFI_INITRD_MEDIA_GUID
> + }, {
> + GRUB_EFI_END_DEVICE_PATH_TYPE,
> + GRUB_EFI_END_ENTIRE_DEVICE_PATH_SUBTYPE,
> + sizeof(grub_efi_device_path_t)
> + }
> +};
> +
> +static initrd_media_device_path_t kernel_lf2_device_path = {
> + {
> + {
> + GRUB_EFI_MEDIA_DEVICE_PATH_TYPE,
> + GRUB_EFI_VENDOR_MEDIA_DEVICE_PATH_SUBTYPE,
> + sizeof(grub_efi_vendor_media_device_path_t),
> + },
> + XEN_EFI_KERNEL_MEDIA_GUID
> + }, {
> + GRUB_EFI_END_DEVICE_PATH_TYPE,
> + GRUB_EFI_END_ENTIRE_DEVICE_PATH_SUBTYPE,
> + sizeof(grub_efi_device_path_t)
> + }
> +};
> +
> +typedef struct lf2
> +{
> + grub_efi_load_file2_t lf2;
> + grub_efi_handle_t handle;
> + initrd_media_device_path_t *media;
> +} lf2_t;
> +
> +static grub_efi_status_t __grub_efi_api
> +grub_efi_load_file2 (grub_efi_load_file2_t *this,
> + grub_efi_device_path_t *device_path,
> + grub_efi_boolean_t boot_policy,
> + grub_efi_uintn_t *buffer_size,
> + void *buffer);
> +static void lf2_init(lf2_t *lf2, initrd_media_device_path_t *media);
> +static grub_err_t lf2_start(lf2_t *lf2);
> +static void lf2_done(lf2_t *lf2);
> +
> struct xen_boot_binary
> {
> struct xen_boot_binary *next;
> @@ -80,6 +130,8 @@ struct xen_boot_binary
>
> char *cmdline;
> int cmdline_size;
> +
> + lf2_t lf2;
> };
>
> static grub_dl_t my_mod;
> @@ -289,6 +341,8 @@ single_binary_unload (struct xen_boot_binary *binary)
> binary->cmdline, binary->cmdline_size);
> }
>
> + lf2_done (&binary->lf2);
> +
> if (!binary->is_hypervisor)
> grub_list_remove (GRUB_AS_LIST (binary));
>
> @@ -393,6 +447,7 @@ grub_cmd_xen_module (grub_command_t cmd
> __attribute__((unused)),
> struct xen_boot_binary *module = NULL;
> grub_file_t file = 0;
> int nounzip = 0;
> + initrd_media_device_path_t *media;
>
> if (!argc)
> {
> @@ -427,6 +482,19 @@ grub_cmd_xen_module (grub_command_t cmd
> __attribute__((unused)),
>
> module->is_hypervisor = false;
> module->align = 4096;
> + switch (grub_list_length (GRUB_AS_LIST (module_head)))
> + {
> + case MODULE_IMAGE:
> + media = &kernel_lf2_device_path;
> + break;
> + case MODULE_INITRD:
> + media = &initrd_lf2_device_path;
> + break;
> + default:
> + media = NULL;
> + break;
> + }
> + lf2_init(&module->lf2, media);
>
> grub_dprintf ("xen_loader", "Init module and node info\n");
>
> @@ -438,7 +506,10 @@ grub_cmd_xen_module (grub_command_t cmd
> __attribute__((unused)),
>
> xen_boot_binary_load (module, file, argc, argv);
> if (grub_errno == GRUB_ERR_NONE)
> - grub_list_push (GRUB_AS_LIST_P (&module_head), GRUB_AS_LIST (module));
> + {
> + grub_list_push (GRUB_AS_LIST_P (&module_head), GRUB_AS_LIST (module));
> + lf2_start (&module->lf2);
> + }
>
> fail:
> if (file)
> @@ -505,6 +576,105 @@ fail:
> return grub_errno;
> }
>
> +static void
> +lf2_init(lf2_t *lf2, initrd_media_device_path_t *media)
> +{
> + lf2->lf2.load_file = grub_efi_load_file2;
> + lf2->handle = NULL;
> + lf2->media = media;
> +}
> +
> +static grub_err_t
> +lf2_start(lf2_t *lf2)
> +{
> + grub_efi_boot_services_t *b = grub_efi_system_table->boot_services;
> + grub_efi_status_t status;
> +
> + if (lf2->handle)
> + return GRUB_ERR_NONE;
> +
> + status = b->install_multiple_protocol_interfaces (&lf2->handle,
> + &load_file2_guid,
> + &lf2->lf2,
> + &device_path_guid,
> + lf2->media,
> + NULL);
> + if (status == GRUB_EFI_OUT_OF_RESOURCES)
> + {
> + grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory"));
> + return grub_errno;
> + }
> + else if (status != GRUB_EFI_SUCCESS)
> + {
> + grub_error (GRUB_ERR_BAD_ARGUMENT, N_("failed to install protocols"));
> + return grub_errno;
> + }
> +
> + return GRUB_ERR_NONE;
> +}
> +
> +static void
> +lf2_done(lf2_t *lf2)
> +{
> + grub_efi_boot_services_t *b = grub_efi_system_table->boot_services;
> +
> + if (!lf2->handle)
> + return;
> +
> + b->uninstall_multiple_protocol_interfaces (lf2->handle,
> + &load_file2_guid,
> + &lf2->lf2,
> + &device_path_guid,
> + lf2->media,
> + NULL);
> + lf2->handle = NULL;
> +}
> +
> +
> +static grub_efi_status_t __grub_efi_api
> +grub_efi_load_file2 (grub_efi_load_file2_t *this,
> + grub_efi_device_path_t *device_path,
> + grub_efi_boolean_t boot_policy,
> + grub_efi_uintn_t *buffer_size,
> + void *buffer)
> +{
> + grub_efi_uintn_t size;
> + struct xen_boot_binary *binary, *module;
> + const void *src;
> +
> + binary = NULL;
> + FOR_LIST_ELEMENTS (module, module_head)
> + if (this == &module->lf2.lf2)
> + {
> + binary = module;
> + break;
> + }
> +
> + if (!binary || buffer_size == NULL)
> + return GRUB_EFI_INVALID_PARAMETER;
> +
> + if (device_path->type != GRUB_EFI_END_DEVICE_PATH_TYPE ||
> + device_path->subtype != GRUB_EFI_END_ENTIRE_DEVICE_PATH_SUBTYPE)
> + return GRUB_EFI_NOT_FOUND;
> +
> + if (boot_policy)
> + return GRUB_EFI_UNSUPPORTED;
> +
> + size = binary->size;
> + if (buffer == NULL || *buffer_size < size)
> + {
> + *buffer_size = size;
> + return GRUB_EFI_BUFFER_TOO_SMALL;
> + }
> +
This is not compliant with the spec:
> BufferSize ... On output with a return code of EFI_SUCCESS, the amount of
> data transferred to Buffer.
It looks like you copied this from the EFI Linux loader which has the same
issue.
Ross
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