Re: [kvm-unit-tests PATCH v2 09/18] lib/efi: Add support for loading the initrd

Nikos Nikoleris
2024-03-04T07:44:13Z

On 27/02/2024 19:21, Andrew Jones wrote:
> When loading non-efi tests with QEMU's '-kernel' option we also load
> an environ with the '-initrd' option. Now that efi tests can also be
> loaded with the '-kernel' option also provide the '-initrd' environ.
> For EFI, we use the EFI_LOAD_FILE2_PROTOCOL_GUID protocol to load
> LINUX_EFI_INITRD_MEDIA_GUID. Each architecture which wants to use the
> initrd for the environ will need to call setup_env() on the initrd
> data. As usual, the new efi function is heavily influenced by Linux's
> implementation.
>
> Signed-off-by: Andrew Jones <andrew.jones@linux.dev>

Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>

Thanks,

Nikos

> ---
> lib/efi.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++
> lib/linux/efi.h | 27 ++++++++++++++++++++
> 2 files changed, 92 insertions(+)
>
> diff --git a/lib/efi.c b/lib/efi.c
> index 0785bd3e8916..edfcc80ef114 100644
> --- a/lib/efi.c
> +++ b/lib/efi.c
> @@ -14,6 +14,10 @@
> #include "efi.h"
> #include "libfdt/libfdt.h"
>
> +/* From each arch */
> +extern char *initrd;
> +extern u32 initrd_size;
> +
> /* From lib/argv.c */
> extern int __argc, __envc;
> extern char *__argv[100];
> @@ -303,6 +307,65 @@ static bool efi_get_fdt(efi_handle_t handle, struct efi_loaded_image_64 *image,
> return fdt_check_header(*fdt) == 0;
> }
>
> +static const struct {
> + struct efi_vendor_dev_path vendor;
> + struct efi_generic_dev_path end;
> +} __packed initrd_dev_path = {
> + {
> + {
> + EFI_DEV_MEDIA,
> + EFI_DEV_MEDIA_VENDOR,
> + sizeof(struct efi_vendor_dev_path),
> + },
> + LINUX_EFI_INITRD_MEDIA_GUID
> + }, {
> + EFI_DEV_END_PATH,
> + EFI_DEV_END_ENTIRE,
> + sizeof(struct efi_generic_dev_path)
> + }
> +};
> +
> +static void efi_load_initrd(void)
> +{
> + efi_guid_t lf2_proto_guid = EFI_LOAD_FILE2_PROTOCOL_GUID;
> + efi_device_path_protocol_t *dp;
> + efi_load_file2_protocol_t *lf2;
> + efi_handle_t handle;
> + efi_status_t status;
> + unsigned long file_size = 0;
> +
> + initrd = NULL;
> + initrd_size = 0;
> +
> + dp = (efi_device_path_protocol_t *)&initrd_dev_path;
> + status = efi_bs_call(locate_device_path, &lf2_proto_guid, &dp, &handle);
> + if (status != EFI_SUCCESS)
> + return;
> +
> + status = efi_bs_call(handle_protocol, handle, &lf2_proto_guid, (void **)&lf2);
> + assert(status == EFI_SUCCESS);
> +
> + status = efi_call_proto(lf2, load_file, dp, false, &file_size, NULL);
> + assert(status == EFI_BUFFER_TOO_SMALL);
> +
> + status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, file_size, (void **)&initrd);
> + assert(status == EFI_SUCCESS);
> +
> + status = efi_call_proto(lf2, load_file, dp, false, &file_size, (void *)initrd);
> + assert(status == EFI_SUCCESS);
> +
> + initrd_size = (u32)file_size;
> +
> + /*
> + * UEFI appends initrd=initrd to the command line when an initrd is present.
> + * Remove it in order to avoid confusing unit tests.
> + */
> + if (!strcmp(__argv[__argc - 1], "initrd=initrd")) {
> + __argv[__argc - 1] = NULL;
> + __argc -= 1;
> + }
> +}
> +
> efi_status_t efi_main(efi_handle_t handle, efi_system_table_t *sys_tab)
> {
> int ret;
> @@ -341,6 +404,8 @@ efi_status_t efi_main(efi_handle_t handle, efi_system_table_t *sys_tab)
> }
> setup_args(cmdline_ptr);
>
> + efi_load_initrd();
> +
> efi_bootinfo.fdt_valid = efi_get_fdt(handle, image, &efi_bootinfo.fdt);
> /* Set up efi_bootinfo */
> efi_bootinfo.mem_map.map = &map;
> diff --git a/lib/linux/efi.h b/lib/linux/efi.h
> index 92d798f79767..8fa23ad078ce 100644
> --- a/lib/linux/efi.h
> +++ b/lib/linux/efi.h
> @@ -70,6 +70,9 @@ typedef guid_t efi_guid_t;
>
> #define LOADED_IMAGE_PROTOCOL_GUID EFI_GUID(0x5b1b31a1, 0x9562, 0x11d2, 0x8e, 0x3f, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b)
>
> +#define EFI_LOAD_FILE2_PROTOCOL_GUID EFI_GUID(0x4006c0c1, 0xfcb3, 0x403e, 0x99, 0x6d, 0x4a, 0x6c, 0x87, 0x24, 0xe0, 0x6d)
> +#define LINUX_EFI_INITRD_MEDIA_GUID EFI_GUID(0x5568e427, 0x68fc, 0x4f3d, 0xac, 0x74, 0xca, 0x55, 0x52, 0x31, 0xcc, 0x68)
> +
> typedef struct {
> efi_guid_t guid;
> void *table;
> @@ -248,6 +251,12 @@ struct efi_generic_dev_path {
> u16 length;
> } __packed;
>
> +struct efi_vendor_dev_path {
> + struct efi_generic_dev_path header;
> + efi_guid_t vendorguid;
> + u8 vendordata[];
> +} __packed;
> +
> typedef struct efi_generic_dev_path efi_device_path_protocol_t;
>
> /*
> @@ -449,6 +458,19 @@ typedef struct _efi_simple_file_system_protocol efi_simple_file_system_protocol_
> typedef struct _efi_file_protocol efi_file_protocol_t;
> typedef efi_simple_file_system_protocol_t efi_file_io_interface_t;
> typedef efi_file_protocol_t efi_file_t;
> +typedef union efi_load_file_protocol efi_load_file_protocol_t;
> +typedef union efi_load_file_protocol efi_load_file2_protocol_t;
> +
> +union efi_load_file_protocol {
> + struct {
> + efi_status_t (__efiapi *load_file)(efi_load_file_protocol_t *,
> + efi_device_path_protocol_t *,
> + bool, unsigned long *, void *);
> + };
> + struct {
> + u32 load_file;
> + } mixed_mode;
> +};
>
> typedef efi_status_t efi_simple_file_system_protocol_open_volume(
> efi_simple_file_system_protocol_t *this,
> @@ -544,7 +566,12 @@ typedef struct {
> efi_char16_t file_name[1];
> } efi_file_info_t;
>
> +#define efi_fn_call(inst, func, ...) (inst)->func(__VA_ARGS__)
> #define efi_bs_call(func, ...) efi_system_table->boottime->func(__VA_ARGS__)
> #define efi_rs_call(func, ...) efi_system_table->runtime->func(__VA_ARGS__)
> +#define efi_call_proto(inst, func, ...) ({ \
> + __typeof__(inst) __inst = (inst); \
> + efi_fn_call(__inst, func, __inst, ##__VA_ARGS__); \
> +})
>
> #endif /* __LINUX_UEFI_H */