[U-Boot] [PATCH v2 4/4] x86: qemu: add the ability to load and link ACPI tables from QEMU
Miao Yan
yanmiaobest at gmail.com
Wed Jan 20 05:24:25 CET 2016
This patch adds the ability to load and link ACPI tables provided by QEMU.
QEMU tells guests how to load and patch ACPI tables through its fw_cfg
interface, by adding a firmware file 'etc/table-loader'. Guests are
supposed to parse this file and execute corresponding QEMU commands.
Signed-off-by: Miao Yan <yanmiaobest at gmail.com>
---
Changes in v2:
- add function comment
- improve error handling
arch/x86/cpu/qemu/fw_cfg.c | 253 ++++++++++++++++++++++++++++++++++++++++++
arch/x86/include/asm/fw_cfg.h | 61 ++++++++++
arch/x86/lib/acpi_table.c | 4 +
3 files changed, 318 insertions(+)
diff --git a/arch/x86/cpu/qemu/fw_cfg.c b/arch/x86/cpu/qemu/fw_cfg.c
index bcd34af..5ea7a6e 100644
--- a/arch/x86/cpu/qemu/fw_cfg.c
+++ b/arch/x86/cpu/qemu/fw_cfg.c
@@ -10,7 +10,10 @@
#include <malloc.h>
#include <asm/io.h>
#include <asm/fw_cfg.h>
+#include <asm/tables.h>
+#include <asm/e820.h>
#include <linux/list.h>
+#include <memalign.h>
static bool fwcfg_present;
static bool fwcfg_dma_present;
@@ -204,6 +207,256 @@ err:
return -ENOMEM;
}
+#ifdef CONFIG_QEMU_ACPI_TABLE
+static struct fw_file *qemu_fwcfg_find_file(const char *name)
+{
+ struct list_head *entry;
+ struct fw_file *file;
+
+ list_for_each(entry, &fw_list) {
+ file = list_entry(entry, struct fw_file, list);
+ if (!strcmp(file->cfg.name, name))
+ return file;
+ }
+
+ return NULL;
+}
+
+/*
+ * This function allocates memory for ACPI tables
+ *
+ * @entry : BIOS linker command entry which tells where to allocate memory
+ * (either high memory or low memory)
+ * @addr : The address that should be used for low memory allcation. If the
+ * memory allocation request is 'ZONE_HIGH' then this parameter will
+ * be ignored.
+ * @return: 0 on success, or negative value on failure
+ */
+static int bios_linker_allocate(struct bios_linker_entry *entry,
+ unsigned long *addr)
+{
+ uint32_t size, align;
+ struct fw_file *file;
+ unsigned long aligned_addr;
+
+ align = le32_to_cpu(entry->alloc.align);
+ /* align must be power of 2 */
+ if (align & (align - 1)) {
+ printf("error: wrong alignment %u\n", align);
+ return -EINVAL;
+ }
+
+ file = qemu_fwcfg_find_file(entry->alloc.file);
+ if (!file) {
+ printf("error: can't find file %s\n", entry->alloc.file);
+ return -ENOENT;
+ }
+
+ size = be32_to_cpu(file->cfg.size);
+
+ /*
+ * ZONE_HIGH means we need to allocate from high memory, since
+ * malloc space is already at the end of RAM, so we directly use it.
+ * If allocation zone is ZONE_FSEG, then we use the 'addr' passed
+ * in which is low memory
+ */
+ if (entry->alloc.zone == BIOS_LINKER_LOADER_ALLOC_ZONE_HIGH) {
+ aligned_addr = (unsigned long)memalign(align, size);
+ if (!aligned_addr) {
+ printf("error: allocating resource\n");
+ return -ENOMEM;
+ }
+ } else if (entry->alloc.zone == BIOS_LINKER_LOADER_ALLOC_ZONE_FSEG) {
+ aligned_addr = ALIGN(*addr, align);
+ } else {
+ printf("error: invalid allocation zone\n");
+ return -EINVAL;
+ }
+
+ debug("bios_linker_allocate: allocate file %s, size %u, zone %d, align %u, addr 0x%lx\n",
+ file->cfg.name, size, entry->alloc.zone, align, aligned_addr);
+
+ qemu_fwcfg_read_entry(be16_to_cpu(file->cfg.select),
+ size, (void *)aligned_addr);
+ file->addr = aligned_addr;
+
+ /* adjust address for low memory allocation */
+ if (entry->alloc.zone == BIOS_LINKER_LOADER_ALLOC_ZONE_FSEG)
+ *addr = (aligned_addr + size);
+
+ return 0;
+}
+
+/*
+ * This function patches ACPI tables previously loaded
+ * by bios_linker_allocate()
+ *
+ * @entry : BIOS linker command entry which tells how to patch
+ * ACPI tables
+ * @return: 0 on success, or negative value on failure
+ */
+static int bios_linker_add_pointer(struct bios_linker_entry *entry)
+{
+ struct fw_file *dest, *src;
+ uint32_t offset = le32_to_cpu(entry->pointer.offset);
+ uint64_t pointer = 0;
+
+ dest = qemu_fwcfg_find_file(entry->pointer.dest_file);
+ if (!dest || !dest->addr)
+ return -ENOENT;
+ src = qemu_fwcfg_find_file(entry->pointer.src_file);
+ if (!src || !src->addr)
+ return -ENOENT;
+
+ debug("bios_linker_add_pointer: dest->addr 0x%lx, src->addr 0x%lx, offset 0x%x size %u, 0x%llx\n",
+ dest->addr, src->addr, offset, entry->pointer.size, pointer);
+
+ memcpy(&pointer, (char *)dest->addr + offset, entry->pointer.size);
+ pointer = le64_to_cpu(pointer);
+ pointer += (unsigned long)src->addr;
+ pointer = cpu_to_le64(pointer);
+ memcpy((char *)dest->addr + offset, &pointer, entry->pointer.size);
+
+ return 0;
+}
+
+/*
+ * This function updates checksum fields of ACPI tables previously loaded
+ * by bios_linker_allocate()
+ *
+ * @entry : BIOS linker command entry which tells where to update ACPI table
+ * checksums
+ * @return: 0 on success, or negative value on failure
+ */
+static int bios_linker_add_checksum(struct bios_linker_entry *entry)
+{
+ struct fw_file *file;
+ uint8_t *data, cksum = 0;
+ uint8_t *cksum_start;
+
+ file = qemu_fwcfg_find_file(entry->cksum.file);
+ if (!file || !file->addr)
+ return -ENOENT;
+
+ data = (uint8_t *)(file->addr + le32_to_cpu(entry->cksum.offset));
+ cksum_start = (uint8_t *)(file->addr + le32_to_cpu(entry->cksum.start));
+ cksum = table_compute_checksum(cksum_start,
+ le32_to_cpu(entry->cksum.length));
+ *data = cksum;
+
+ return 0;
+}
+
+unsigned install_e820_map(unsigned max_entries, struct e820entry *entries)
+{
+ entries[0].addr = 0;
+ entries[0].size = ISA_START_ADDRESS;
+ entries[0].type = E820_RAM;
+
+ entries[1].addr = ISA_START_ADDRESS;
+ entries[1].size = ISA_END_ADDRESS - ISA_START_ADDRESS;
+ entries[1].type = E820_RESERVED;
+
+ /*
+ * since we use memalign(malloc) to allocate high memory for
+ * storing ACPI tables, we need to reserve them in e820 tables,
+ * otherwise kernel will reclaim them and data will be corrupted
+ */
+ entries[2].addr = ISA_END_ADDRESS;
+ entries[2].size = gd->relocaddr - TOTAL_MALLOC_LEN - ISA_END_ADDRESS;
+ entries[2].type = E820_RAM;
+
+ /* for simplicity, reserve entire malloc space */
+ entries[3].addr = gd->relocaddr - TOTAL_MALLOC_LEN;
+ entries[3].size = TOTAL_MALLOC_LEN;
+ entries[3].type = E820_RESERVED;
+
+ entries[4].addr = gd->relocaddr;
+ entries[4].size = gd->ram_size - gd->relocaddr;
+ entries[4].type = E820_RESERVED;
+
+ entries[5].addr = CONFIG_PCIE_ECAM_BASE;
+ entries[5].size = CONFIG_PCIE_ECAM_SIZE;
+ entries[5].type = E820_RESERVED;
+
+ return 6;
+}
+
+/* This function loads and patches ACPI tables provided by QEMU */
+unsigned long write_acpi_tables(unsigned long addr)
+{
+ int i, ret = 0;
+ struct fw_file *file;
+ struct bios_linker_entry *table_loader;
+ struct bios_linker_entry *entry;
+ uint32_t size;
+ struct list_head *list;
+
+ /* make sure fw_list is loaded */
+ ret = qemu_fwcfg_read_firmware_list();
+ if (ret) {
+ printf("error: can't read firmware file list\n");
+ return addr;
+ }
+
+ file = qemu_fwcfg_find_file("etc/table-loader");
+ if (!file) {
+ printf("error: can't find etc/table-loader\n");
+ return addr;
+ }
+
+ size = be32_to_cpu(file->cfg.size);
+ if ((size % sizeof(*entry)) != 0) {
+ printf("error: table-loader maybe corrupted\n");
+ return addr;
+ }
+
+ table_loader = malloc(size);
+ if (!table_loader) {
+ printf("error: no memory for table-loader\n");
+ return addr;
+ }
+
+ qemu_fwcfg_read_entry(be16_to_cpu(file->cfg.select),
+ size, table_loader);
+
+ for (i = 0; i < (size / sizeof(*entry)); i++) {
+ entry = table_loader + i;
+ switch (le32_to_cpu(entry->command)) {
+ case BIOS_LINKER_LOADER_COMMAND_ALLOCATE:
+ ret = bios_linker_allocate(entry, &addr);
+ if (ret)
+ goto out;
+ break;
+ case BIOS_LINKER_LOADER_COMMAND_ADD_POINTER:
+ ret = bios_linker_add_pointer(entry);
+ if (ret)
+ goto out;
+ break;
+ case BIOS_LINKER_LOADER_COMMAND_ADD_CHECKSUM:
+ ret = bios_linker_add_checksum(entry);
+ if (ret)
+ goto out;
+ break;
+ default:
+ break;
+ }
+ }
+
+out:
+ if (ret) {
+ list_for_each(list, &fw_list) {
+ file = list_entry(list, struct fw_file, list);
+ if (file->addr)
+ free((void *)file->addr);
+ }
+ }
+
+ free(table_loader);
+ return addr;
+}
+#endif
+
static int qemu_fwcfg_list_firmware(void)
{
int ret;
diff --git a/arch/x86/include/asm/fw_cfg.h b/arch/x86/include/asm/fw_cfg.h
index 2acf43e..e9450c6 100644
--- a/arch/x86/include/asm/fw_cfg.h
+++ b/arch/x86/include/asm/fw_cfg.h
@@ -47,11 +47,23 @@ enum qemu_fwcfg_items {
FW_CFG_INVALID = 0xffff,
};
+enum {
+ BIOS_LINKER_LOADER_COMMAND_ALLOCATE = 0x1,
+ BIOS_LINKER_LOADER_COMMAND_ADD_POINTER = 0x2,
+ BIOS_LINKER_LOADER_COMMAND_ADD_CHECKSUM = 0x3,
+};
+
+enum {
+ BIOS_LINKER_LOADER_ALLOC_ZONE_HIGH = 0x1,
+ BIOS_LINKER_LOADER_ALLOC_ZONE_FSEG = 0x2,
+};
+
#define FW_CFG_FILE_SLOTS 0x10
#define FW_CFG_MAX_ENTRY (FW_CFG_FILE_FIRST + FW_CFG_FILE_SLOTS)
#define FW_CFG_ENTRY_MASK ~(FW_CFG_WRITE_CHANNEL | FW_CFG_ARCH_LOCAL)
#define FW_CFG_MAX_FILE_PATH 56
+#define BIOS_LINKER_LOADER_FILESZ FW_CFG_MAX_FILE_PATH
#define QEMU_FW_CFG_SIGNATURE (('Q' << 24) | ('E' << 16) | ('M' << 8) | 'U')
@@ -81,6 +93,55 @@ struct fw_cfg_dma_access {
__be64 address;
};
+struct bios_linker_entry {
+ __le32 command;
+ union {
+ /*
+ * COMMAND_ALLOCATE - allocate a table from @alloc.file
+ * subject to @alloc.align alignment (must be power of 2)
+ * and @alloc.zone (can be HIGH or FSEG) requirements.
+ *
+ * Must appear exactly once for each file, and before
+ * this file is referenced by any other command.
+ */
+ struct {
+ char file[BIOS_LINKER_LOADER_FILESZ];
+ __le32 align;
+ uint8_t zone;
+ } alloc;
+
+ /*
+ * COMMAND_ADD_POINTER - patch the table (originating from
+ * @dest_file) at @pointer.offset, by adding a pointer to the
+ * table originating from @src_file. 1,2,4 or 8 byte unsigned
+ * addition is used depending on @pointer.size.
+ */
+ struct {
+ char dest_file[BIOS_LINKER_LOADER_FILESZ];
+ char src_file[BIOS_LINKER_LOADER_FILESZ];
+ __le32 offset;
+ uint8_t size;
+ } pointer;
+
+ /*
+ * COMMAND_ADD_CHECKSUM - calculate checksum of the range
+ * specified by @cksum_start and @cksum_length fields,
+ * and then add the value at @cksum.offset.
+ * Checksum simply sums -X for each byte X in the range
+ * using 8-bit math.
+ */
+ struct {
+ char file[BIOS_LINKER_LOADER_FILESZ];
+ __le32 offset;
+ __le32 start;
+ __le32 length;
+ } cksum;
+
+ /* padding */
+ char pad[124];
+ };
+} __packed;
+
/**
* Initialize QEMU fw_cfg interface
*/
diff --git a/arch/x86/lib/acpi_table.c b/arch/x86/lib/acpi_table.c
index ab1db7e..2ec5ad2 100644
--- a/arch/x86/lib/acpi_table.c
+++ b/arch/x86/lib/acpi_table.c
@@ -331,6 +331,10 @@ static void acpi_create_ssdt_generator(acpi_header_t *ssdt,
ssdt->checksum = table_compute_checksum((void *)ssdt, ssdt->length);
}
+/*
+ * QEMU's version of write_acpi_tables is defined in
+ * arch/x86/cpu/qemu/fw_cfg.c
+ */
unsigned long write_acpi_tables(unsigned long start)
{
unsigned long current;
--
1.9.1
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