Re: [Qemu-devel] [PATCH 1/3] linux-user: introduce functions to detect CPU type

[Richard Henderson]

On 01/13/2018 06:48 AM, Laurent Vivier wrote:
> From: YunQiang Su <address@hidden>
> 
> Move CPU type name selection to a function,
> and add a function to return ELF e_flags.
> 
> [lv: splitted the patch and some cleanup in get_elf_eflags()]
> Signed-off-by: Laurent Vivier <address@hidden>
> ---

This needs to be split.

> +int get_elf_eflags(int fd, uint32_t *eflags)
> +{
> +    struct elfhdr ehdr;
> +    off_t offset;
> +    int ret;
> +
> +    /* Read ELF header */
> +    offset = lseek(fd, 0, SEEK_SET);
> +    if (offset == (off_t) -1) {
> +        return -1;
> +    }
> +    ret = read(fd, &ehdr, sizeof(ehdr));
> +    if (ret < sizeof(ehdr)) {
> +        return -1;
> +    }

There is no reason to read the elf header twice -- e_flags has already been
stored in the struct image_info.

> +static const char *get_cpu_model(int fd)
> +{
> +#if defined(TARGET_I386)
> +#ifdef TARGET_X86_64
> +    return "qemu64";
> +#else
> +    return "qemu32";
> +#endif

This should be our opportunity to split this ifdef chain into small inline
functions within linux-user/*/target_cpu.h.  Pass the e_flags value directly
instead of a file descriptor.


r~