Re: [Qemu-devel] [PATCH v2] Add optionrom compatible with fw_cfg DMA version

[Paolo Bonzini]

On 18/01/2016 10:59, Marc Marí wrote:
> This optionrom is based on linuxboot.S.
> 
> Signed-off-by: Marc Marí <address@hidden>

Reviewed-by: Paolo Bonzini <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 | 262 
> ++++++++++++++++++++++++++++++++++++++
>  pc-bios/optionrom/optionrom.h     |   4 +-
>  7 files changed, 285 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..9c355fd
> --- /dev/null
> +++ b/pc-bios/optionrom/linuxboot_dma.c
> @@ -0,0 +1,262 @@
> +/*
> + * 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"
> +"_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;
> +
> +static inline void outl(uint32_t value, uint16_t port) {
> +    asm("outl %0, %w1" : : "a"(value), "Nd"(port));
> +}
> +
> +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_addr32(const void *addr) {
> +    uint32_t val;
> +    asm("addr32 movl %1, %0" : "=r"(val) : "g"(addr));
> +    barrier();
> +    return 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;
> +}
> +
> +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);
> +
> +    }
> +
> +    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);
> +
> +    /* 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;                   \
>