[Qemu-devel] [PATCH] Add optionrom compatible with fw_cfg DMA version

[Marc Marí]

This optionrom is based on linuxboot.S.

Signed-off-by: Marc Marí <address@hidden>
---
 .gitignore                        |   4 +
 hw/i386/pc.c                      |   9 +-
 hw/nvram/fw_cfg.c                 |   2 +-
 include/hw/nvram/fw_cfg.h         |   1 +
 pc-bios/optionrom/Makefile        |   8 +-
 pc-bios/optionrom/linuxboot_dma.c | 338 ++++++++++++++++++++++++++++++++++++++
 pc-bios/optionrom/optionrom.h     |   4 +-
 7 files changed, 361 insertions(+), 5 deletions(-)
 create mode 100644 pc-bios/optionrom/linuxboot_dma.c

diff --git a/.gitignore b/.gitignore
index 88a80ff..101d1e0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -94,6 +94,10 @@
 /pc-bios/optionrom/linuxboot.bin
 /pc-bios/optionrom/linuxboot.raw
 /pc-bios/optionrom/linuxboot.img
+/pc-bios/optionrom/linuxboot_dma.asm
+/pc-bios/optionrom/linuxboot_dma.bin
+/pc-bios/optionrom/linuxboot_dma.raw
+/pc-bios/optionrom/linuxboot_dma.img
 /pc-bios/optionrom/multiboot.asm
 /pc-bios/optionrom/multiboot.bin
 /pc-bios/optionrom/multiboot.raw
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 459260b..00339fa 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1007,8 +1007,13 @@ static void load_linux(PCMachineState *pcms,
     fw_cfg_add_i32(fw_cfg, FW_CFG_SETUP_SIZE, setup_size);
     fw_cfg_add_bytes(fw_cfg, FW_CFG_SETUP_DATA, setup, setup_size);
 
-    option_rom[nb_option_roms].name = "linuxboot.bin";
-    option_rom[nb_option_roms].bootindex = 0;
+    if (fw_cfg_dma_enabled(fw_cfg)) {
+        option_rom[nb_option_roms].name = "linuxboot_dma.bin";
+        option_rom[nb_option_roms].bootindex = 0;
+    } else {
+        option_rom[nb_option_roms].name = "linuxboot.bin";
+        option_rom[nb_option_roms].bootindex = 0;
+    }
     nb_option_roms++;
 }
 
diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index a1d650d..d0a5753 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -546,7 +546,7 @@ static bool is_version_1(void *opaque, int version_id)
     return version_id == 1;
 }
 
-static bool fw_cfg_dma_enabled(void *opaque)
+bool fw_cfg_dma_enabled(void *opaque)
 {
     FWCfgState *s = opaque;
 
diff --git a/include/hw/nvram/fw_cfg.h b/include/hw/nvram/fw_cfg.h
index 664eaf6..953e58d 100644
--- a/include/hw/nvram/fw_cfg.h
+++ b/include/hw/nvram/fw_cfg.h
@@ -219,6 +219,7 @@ FWCfgState *fw_cfg_init_mem_wide(hwaddr ctl_addr,
                                  hwaddr dma_addr, AddressSpace *dma_as);
 
 FWCfgState *fw_cfg_find(void);
+bool fw_cfg_dma_enabled(void *opaque);
 
 #endif /* NO_QEMU_PROTOS */
 
diff --git a/pc-bios/optionrom/Makefile b/pc-bios/optionrom/Makefile
index ce4852a..076f351 100644
--- a/pc-bios/optionrom/Makefile
+++ b/pc-bios/optionrom/Makefile
@@ -2,6 +2,7 @@ all: build-all
 # Dummy command so that make thinks it has done something
        @true
 
+BULD_DIR=$(CURDIR)
 include ../../config-host.mak
 include $(SRC_PATH)/rules.mak
 
@@ -11,15 +12,20 @@ $(call set-vpath, $(SRC_PATH)/pc-bios/optionrom)
 
 CFLAGS := -Wall -Wstrict-prototypes -Werror -fomit-frame-pointer -fno-builtin
 CFLAGS += -I$(SRC_PATH)
+CFLAGS += -I$(SRC_PATH)/include
 CFLAGS += $(call cc-option, $(CFLAGS), -fno-stack-protector)
 CFLAGS += $(CFLAGS_NOPIE)
+CFLAGS += -m32
 QEMU_CFLAGS = $(CFLAGS)
 
-build-all: multiboot.bin linuxboot.bin kvmvapic.bin
+build-all: multiboot.bin linuxboot.bin linuxboot_dma.bin kvmvapic.bin
 
 # suppress auto-removal of intermediate files
 .SECONDARY:
 
+linuxboot_dma.img: linuxboot_dma.o
+       $(call quiet-command,$(LD) $(LDFLAGS_NOPIE) -m elf_i386 -static -Ttext 
0 -e _start -s -o $@ $<,"  Building $(TARGET_DIR)$@")
+
 %.img: %.o
        $(call quiet-command,$(LD) $(LDFLAGS_NOPIE) -Ttext 0 -e _start -s -o $@ 
$<,"  Building $(TARGET_DIR)$@")
 
diff --git a/pc-bios/optionrom/linuxboot_dma.c 
b/pc-bios/optionrom/linuxboot_dma.c
new file mode 100644
index 0000000..c420398
--- /dev/null
+++ b/pc-bios/optionrom/linuxboot_dma.c
@@ -0,0 +1,338 @@
+/*
+ * Linux Boot Option ROM for fw_cfg DMA
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright (c) 2015 Red Hat Inc.
+ *   Authors: Marc Marí <address@hidden>
+ */
+
+asm(
+".text\n"
+".global _start\n"
+"_start:\n"
+"   .short     0xaa55\n"
+"   .byte (_end - _start) / 512\n"
+"   lret\n"
+"   .org 0x18\n"
+"   .short 0\n"
+"   .short _pnph\n"
+"_pnph:\n"
+"   .ascii \"$PnP\"\n"
+"   .byte 0x01\n"
+"   .byte ( _pnph_len / 16 )\n"
+"   .short 0x0000\n"
+"   .byte 0x00\n"
+"   .byte 0x00\n"
+"   .long 0x00000000\n"
+"   .short _manufacturer\n"
+"   .short _product\n"
+"   .long 0x00000000\n"
+"   .short 0x0000\n"
+"   .short 0x0000\n"
+"   .short _bev\n"
+"   .short 0x0000\n"
+"   .short 0x0000\n"
+"   .equ _pnph_len, . - _pnph\n"
+"   .align 4, 0\n"
+".global gdt\n"
+"gdt:\n"
+/* 0x00 */
+"   .byte 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00\n"
+/* 0x08: code segment (base=0, limit=0xfffff,
+ * type=32bit code exec/read, DPL=0, 4k)
+ */
+"   .byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x9a, 0xcf, 0x00\n"
+/* 0x10: data segment (base=0, limit=0xfffff,
+ * type=32bit data read/write, DPL=0, 4k)
+ */
+"   .byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x92, 0xcf, 0x00\n"
+"_bev:\n"
+".code16gcc\n"
+/* DS = CS */
+"   movw %cs, %ax\n"
+"   movw %ax, %ds\n"
+"   movl %esp, %ebp\n"
+"run_linuxboot:\n"
+"   cli\n"
+"   cld\n"
+"   jmp load_kernel\n"
+);
+
+#define C_CODE
+
+/* Do not include all QEMU dependencies */
+#include <stdint.h>
+#include <byteswap.h>
+#include "optionrom.h"
+
+#define BOOT_ROM_PRODUCT "Linux loader"
+
+/* QEMU_CFG_DMA_CONTROL bits */
+#define BIOS_CFG_DMA_CTL_ERROR   0x01
+#define BIOS_CFG_DMA_CTL_READ    0x02
+#define BIOS_CFG_DMA_CTL_SKIP    0x04
+#define BIOS_CFG_DMA_CTL_SELECT  0x08
+
+#define BIOS_CFG_DMA_ADDR_HIGH 0x514
+#define BIOS_CFG_DMA_ADDR_LOW  0x518
+
+#define _stringify(S)   #S
+#define stringify(S) _stringify(S)
+
+#define barrier() asm("": : :"memory")
+
+typedef struct FWCfgDmaAccess {
+    uint32_t control;
+    uint32_t length;
+    uint64_t address;
+} __attribute__((gcc_struct, packed)) FWCfgDmaAccess;
+
+struct length_addr {
+    uint16_t length;
+    uint32_t addr;
+} __attribute__((gcc_struct, packed));
+
+static inline void outl(uint32_t value, uint16_t port) {
+    asm("outl %0, %w1" : : "a"(value), "Nd"(port));
+}
+
+static inline uint16_t read_ds(void) {
+    uint16_t ds;
+    asm("movw %%ds, %w0" : "=r"(ds) : );
+    return ds;
+}
+
+static inline uint16_t readw(const void *addr) {
+    uint16_t val = *(volatile const uint16_t *)addr;
+    barrier();
+    return val;
+}
+
+static inline uint16_t readw_addr32(const void *addr) {
+    uint16_t val;
+    asm("addr32 movw %1, %0" : "=r"(val) : "g"(addr));
+    barrier();
+    return val;
+}
+
+static inline uint32_t readl(const void *addr) {
+    uint32_t val = *(volatile const uint32_t *)addr;
+    barrier();
+    return val;
+}
+
+static inline uint32_t readl_addr32(const void *addr) {
+    uint32_t val;
+    asm("addr32 movl %1, %0" : "=r"(val) : "g"(addr));
+    barrier();
+    return val;
+}
+
+static inline void writel(void *addr, uint32_t val) {
+    barrier();
+    *(volatile uint32_t *)addr = val;
+}
+
+static inline void writel_addr32(void *addr, uint32_t val) {
+    barrier();
+    asm("addr32 movl %0, %1" : : "r"(val), "g"(addr));
+}
+
+static inline uint64_t cpu_to_be64(uint64_t x) {
+    return bswap_64(x);
+}
+
+static inline uint32_t cpu_to_be32(uint32_t x) {
+    return bswap_32(x);
+}
+
+static inline uint32_t be32_to_cpu(uint32_t x) {
+    return bswap_32(x);
+}
+
+static void bios_cfg_read_entry(void *buf, uint16_t entry, uint32_t len)
+{
+    FWCfgDmaAccess access;
+    uint32_t control = (entry << 16) | BIOS_CFG_DMA_CTL_SELECT
+                        | BIOS_CFG_DMA_CTL_READ;
+
+    access.address = cpu_to_be64((uint64_t)(uint32_t)buf);
+    access.length = cpu_to_be32(len);
+    access.control = cpu_to_be32(control);
+
+    barrier();
+
+    outl(cpu_to_be32((uint32_t)&access), BIOS_CFG_DMA_ADDR_LOW);
+
+    while(be32_to_cpu(access.control) & ~BIOS_CFG_DMA_CTL_ERROR) {
+        barrier();
+    }
+}
+
+static uint32_t get_e801_addr(void)
+{
+    uint32_t eax, ebx, ecx, edx;
+    uint32_t ret;
+
+    eax = 0xe801;
+    ebx = 0;
+    ecx = 0;
+    edx = 0;
+    asm("int $0x15\n"
+        : "+a"(eax)
+        : "b"(ebx), "c"(ecx), "d"(edx));
+
+    /* Output could be in AX/BX or CX/DX */
+    if ((uint16_t)ecx || (uint16_t)edx) {
+        if(!(uint16_t)edx) {
+            /* Add 1 MB and convert to bytes */
+            ret = (ecx + 1024) << 10;
+        } else {
+            /* Add 16 MB and convert to bytes */
+            ret = (edx + 256) << 16;
+        }
+    } else {
+        if(!(uint16_t)ebx) {
+            /* Add 1 MB and convert to bytes */
+            ret = (eax + 1024) << 10;
+        } else {
+            /* Add 16 MB and convert to bytes */
+            ret = (ebx + 256) << 16;
+        }
+    }
+
+    return ret;
+}
+
+static void transition32(void)
+{
+    extern void *gdt;
+    uint32_t data_segment;
+    struct length_addr rombios_gdt;
+
+    data_segment = read_ds();
+    rombios_gdt.addr = (uint32_t)((data_segment << 4) + (uint32_t)(&gdt));
+    rombios_gdt.length = (3 * 8) - 1;
+
+    /* Load GDT */
+    asm("data32 lgdt %0" : : "m"(rombios_gdt): "memory");
+
+       /* Get us to protected mode and set ES to a 32 bit segment */
+    asm("mov $1, %%eax\n"
+        "mov %%eax, %%cr0\n"
+        "mov $0x10, %%eax\n"
+        "mov %%eax, %%es\n"
+        : : : "eax");
+
+    /* We're now running in 16-bit CS, but 32-bit ES! */
+}
+
+static void transition16(void)
+{
+    asm("mov $0, %%eax\n"
+        "mov %%eax, %%cr0\n"
+        "mov %%cs, %%ax\n"
+        "mov %%ax, %%es\n"
+        : : : "eax");
+}
+
+void load_kernel(void)
+{
+    void *setup_addr;
+    void *initrd_addr;
+    void *kernel_addr;
+    void *cmdline_addr;
+    uint32_t setup_size;
+    uint32_t initrd_size;
+    uint32_t kernel_size;
+    uint32_t cmdline_size;
+    uint32_t initrd_end_page, max_allowed_page;
+    uint32_t segment_addr, stack_addr;
+
+    bios_cfg_read_entry(&setup_addr, FW_CFG_SETUP_ADDR, 4);
+    bios_cfg_read_entry(&setup_size, FW_CFG_SETUP_SIZE, 4);
+    bios_cfg_read_entry(setup_addr, FW_CFG_SETUP_DATA, setup_size);
+
+    if (readw_addr32(setup_addr + 0x206) < 0x203) {
+        /* Assume initrd_max 0x37ffffff */
+        writel_addr32(setup_addr + 0x22c, 0x37ffffff);
+    }
+
+    bios_cfg_read_entry(&initrd_addr, FW_CFG_INITRD_ADDR, 4);
+    bios_cfg_read_entry(&initrd_size, FW_CFG_INITRD_SIZE, 4);
+
+    initrd_end_page = ((uint32_t)(initrd_addr + initrd_size) & -4096);
+    max_allowed_page = (readl_addr32(setup_addr + 0x22c) & -4096);
+
+    if (initrd_end_page != 0 && max_allowed_page != 0 &&
+        initrd_end_page != max_allowed_page) {
+        /* Initrd at the end of memory. Compute better initrd address
+         * based on e801 data
+         */
+        initrd_addr = (void *)((get_e801_addr() - initrd_size) & -4096);
+        writel_addr32(setup_addr + 0x218, (uint32_t)initrd_addr);
+
+    }
+
+    transition32();
+
+    bios_cfg_read_entry(initrd_addr, FW_CFG_INITRD_DATA, initrd_size);
+
+    bios_cfg_read_entry(&kernel_addr, FW_CFG_KERNEL_ADDR, 4);
+    bios_cfg_read_entry(&kernel_size, FW_CFG_KERNEL_SIZE, 4);
+    bios_cfg_read_entry(kernel_addr, FW_CFG_KERNEL_DATA, kernel_size);
+
+    bios_cfg_read_entry(&cmdline_addr, FW_CFG_CMDLINE_ADDR, 4);
+    bios_cfg_read_entry(&cmdline_size, FW_CFG_CMDLINE_SIZE, 4);
+    bios_cfg_read_entry(cmdline_addr, FW_CFG_CMDLINE_DATA, cmdline_size);
+
+    transition16();
+
+    /* Boot linux */
+    segment_addr = ((uint32_t)setup_addr >> 4);
+    stack_addr = (uint32_t)(cmdline_addr - setup_addr - 16);
+
+    /* As we are changing crytical registers, we cannot leave freedom to the
+     * compiler.
+     */
+    asm("movw %%ax, %%ds\n"
+        "movw %%ax, %%es\n"
+        "movw %%ax, %%fs\n"
+        "movw %%ax, %%gs\n"
+        "movw %%ax, %%ss\n"
+        "movl %%ebx, %%esp\n"
+        "addw $0x20, %%ax\n"
+        "pushw %%ax\n" /* CS */
+        "pushw $0\n" /* IP */
+        /* Clear registers and jump to Linux */
+        "xor %%ebx, %%ebx\n"
+        "xor %%ecx, %%ecx\n"
+        "xor %%edx, %%edx\n"
+        "xor %%edi, %%edi\n"
+        "xor %%ebp, %%ebp\n"
+        "lretw\n"
+        : : "a"(segment_addr), "b"(stack_addr));
+}
+
+asm(
+"_manufacturer:\n"
+".asciz \"QEMU\"\n"
+"_product:\n"
+".asciz "stringify(BOOT_ROM_PRODUCT)"\n"
+".byte 0\n"
+".align 512, 0\n"
+"_end:\n"
+);
+
diff --git a/pc-bios/optionrom/optionrom.h b/pc-bios/optionrom/optionrom.h
index f1a9021..25c765f 100644
--- a/pc-bios/optionrom/optionrom.h
+++ b/pc-bios/optionrom/optionrom.h
@@ -29,7 +29,8 @@
 #define DEBUG_HERE \
        jmp             1f;                             \
        1:
-       
+
+#ifndef C_CODE
 /*
  * Read a variable from the fw_cfg device.
  * Clobbers:   %edx
@@ -49,6 +50,7 @@
        inb             (%dx), %al
        bswap           %eax
 .endm
+#endif
 
 #define read_fw_blob_pre(var)                          \
        read_fw         var ## _SIZE;                   \
-- 
2.4.3