misc: efi-stub: Add helper functions to search/parse multiboot1/2 headers

This patch adds a file containing some helper functions to search or parse
multiboot headers.

Tracked-On: #6241
Signed-off-by: Yifan Liu <yifan1.liu@intel.com>
Signed-off-by: Toshiki Nishioka <toshiki.nishioka@intel.com>

misc/efi-stub/Makefile

@@ -32,7 +32,7 @@
 
 HV_OBJDIR:=build
 HV_SRC:=../../hypervisor
-C_SRCS = boot.c pe.c malloc.c
+C_SRCS = boot.c pe.c malloc.c multiboot.c
 ACRN_OBJS := $(patsubst %.c,$(EFI_OBJDIR)/%.o,$(C_SRCS))
 INCLUDE_PATH += $(INCDIR)/efi
 INCLUDE_PATH += $(HV_SRC)/include/public

misc/efi-stub/multiboot.c

@@ -0,0 +1,136 @@
+/*
+ * Copyright (c) 2021, Intel Corporation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *    * Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *    * Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer
+ *      in the documentation and/or other materials provided with the
+ *      distribution.
+ *    * Neither the name of Intel Corporation nor the names of its
+ *      contributors may be used to endorse or promote products
+ *      derived from this software without specific prior written
+ *      permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <efi.h>
+#include <efilib.h>
+#include "boot.h"
+#include "stdlib.h"
+#include "multiboot.h"
+
+/**
+ * @brief Search the first len bytes in buffer for multiboot1 header.
+ *
+ * @param[in] buffer Buffer to be searched
+ * @param[in] len    Search length
+ *
+ * @return A pointer to the multiboot1 header if found. NULL otherwise.
+ */
+const struct multiboot_header *find_mb1header(const UINT8 *buffer, uint64_t len)
+{
+	const struct multiboot_header *header;
+
+	for (header = (struct multiboot_header *)buffer;
+		((char *)header <= (char *)buffer + len - 12);
+		header = (struct multiboot_header *)((char *)header + MULTIBOOT_HEADER_ALIGN))
+	{
+		if (header->mh_magic == MULTIBOOT_HEADER_MAGIC &&
+			!(header->mh_magic + header->mh_flags + header->mh_checksum))
+			return header;
+	}
+
+	return NULL;
+}
+
+/**
+ * @brief Search the first len bytes in buffer for multiboot2 header.
+ *
+ * @param[in] buffer Buffer to be searched
+ * @param[in] len    Search length
+ *
+ * @return A pointer to the multiboot2 header if found. NULL otherwise.
+ */
+const struct multiboot2_header *find_mb2header(const UINT8 *buffer, uint64_t len)
+{
+	const struct multiboot2_header *header;
+
+	for (header = (const struct multiboot2_header *)buffer;
+		((char *)header <= (char *)buffer + len - 12);
+		header = (struct multiboot2_header *)((uint64_t)header + MULTIBOOT2_HEADER_ALIGN / 4))
+	{
+		if (header->magic == MULTIBOOT2_HEADER_MAGIC &&
+			!(header->magic + header->architecture + header->header_length + header->checksum) &&
+			header->architecture == MULTIBOOT2_ARCHITECTURE_I386)
+			return header;
+	}
+
+	return NULL;
+}
+
+/**
+ * @brief Parse the multiboot2 header and return a list of pointers to the header tags.
+ *
+ * @param[in]  header     Multiboot2 header to be parsed.
+ * @param[out] hv_tags    An hv_mb2header_tag_list struct that contains pointers to all possible
+ *                        tags in a multiboot2 header. If a field in this struct is not NULL, it
+ *                        means the tag was found in the given header. NULL otherwise.
+ *
+ * @return 0 on success. -1 on error.
+ */
+int parse_mb2header(const struct multiboot2_header *header, struct hv_mb2header_tag_list *hv_tags)
+{
+	struct multiboot2_header_tag *tag;
+
+	memset(hv_tags, 0, sizeof(struct hv_mb2header_tag_list));
+
+	for (tag = (struct multiboot2_header_tag *)(header + 1);
+		tag->type != MULTIBOOT2_TAG_TYPE_END;
+		tag = (struct multiboot2_header_tag *)((uint32_t *)tag + ALIGN_UP(tag->size, MULTIBOOT2_TAG_ALIGN) / 4))
+	{
+		switch (tag->type) {
+			case MULTIBOOT2_HEADER_TAG_INFORMATION_REQUEST:
+				/* Ignored. Currently we didn't support all categories of requested information,
+				 * only the part that ACRN requests. So we don't parse the requests here. */
+				break;
+
+			case MULTIBOOT2_HEADER_TAG_ADDRESS:
+				hv_tags->addr = (struct multiboot2_header_tag_address *)tag;
+				break;
+
+			case MULTIBOOT2_HEADER_TAG_ENTRY_ADDRESS:
+				hv_tags->entry = (struct multiboot2_header_tag_entry_address *)tag;
+				break;
+
+			case MULTIBOOT2_HEADER_TAG_RELOCATABLE:
+				hv_tags->reloc = (struct multiboot2_header_tag_relocatable *)tag;
+				break;
+
+			default:
+				Print(L"Unsupported multiboot2 tag type: %d\n", tag->type);
+				return -1;
+		}
+	}
+
+	if (hv_tags->addr && !hv_tags->entry)
+		return -1;
+
+	return 0;
+}

misc/efi-stub/multiboot.h

@@ -375,4 +375,18 @@ struct multiboot2_tag_efi_mmap {
 };
 #endif
 
+struct hv_mb2header_tag_list {
+	struct multiboot2_header_tag_information_request *info_req;
+	struct multiboot2_header_tag_address *addr;
+	struct multiboot2_header_tag_entry_address *entry;
+	struct multiboot2_header_tag_console_flags *console_flags;
+	struct multiboot2_header_tag_framebuffer *frbuf;
+	struct multiboot2_header_tag_module_align *modalign;
+	struct multiboot2_header_tag_relocatable *reloc;
+};
+
+const struct multiboot_header *find_mb1header(const UINT8 *buffer, uint64_t len);
+const struct multiboot2_header *find_mb2header(const UINT8 *buffer, uint64_t len);
+int parse_mb2header(const struct multiboot2_header *header, struct hv_mb2header_tag_list *hv_tags);
+
 #endif /* _MULTIBOOT_H */