[kvm-unit-tests PATCH v3 09/18] lib/efi: Add support for loading the initrd

[Andrew Jones <andrew.jones@linux.dev>]

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.

Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Signed-off-by: Andrew Jones <andrew.jones@linux.dev>
---
 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 4d1126b4a64e..12c66c6ffd1f 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];
@@ -302,6 +306,65 @@ static void *efi_get_fdt(efi_handle_t handle, struct efi_loaded_image_64 *image)
 	return fdt_check_header(fdt) == 0 ? fdt : NULL;
 }
 
+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;
@@ -340,6 +403,8 @@ 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 = efi_get_fdt(handle, image);
 	/* 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 */
-- 
2.44.0