Re: [Qemu-devel] [RFC][PATCH 07/16 v6] target-i386: Add API to add extra memory mapping

[Jan Kiszka]

On 2012-02-09 04:24, Wen Congyang wrote:
> Crash needs extra memory mapping to determine phys_base.
> 
> Signed-off-by: Wen Congyang <address@hidden>
> ---
>  cpu-all.h               |    2 ++
>  target-i386/arch-dump.c |   43 +++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 45 insertions(+), 0 deletions(-)
> 
> diff --git a/cpu-all.h b/cpu-all.h
> index efb5ba3..290c43a 100644
> --- a/cpu-all.h
> +++ b/cpu-all.h
> @@ -530,10 +530,12 @@ int cpu_write_elf64_note(int fd, CPUState *env, int 
> cpuid,
>                           target_phys_addr_t *offset);
>  int cpu_write_elf32_note(int fd, CPUState *env, int cpuid,
>                           target_phys_addr_t *offset);
> +int cpu_add_extra_memory_mapping(MemoryMappingList *list);
>  #else
>  #define cpu_get_memory_mapping(list, env)
>  #define cpu_write_elf64_note(fd, env, cpuid, offset) ({ -1; })
>  #define cpu_write_elf32_note(fd, env, cpuid, offset) ({ -1; })
> +#define cpu_add_extra_memory_mapping(list) ({ 0; })
>  #endif
>  
>  #endif /* CPU_ALL_H */
> diff --git a/target-i386/arch-dump.c b/target-i386/arch-dump.c
> index 4c0ff77..d96f6ae 100644
> --- a/target-i386/arch-dump.c
> +++ b/target-i386/arch-dump.c
> @@ -495,3 +495,46 @@ int cpu_write_elf32_note(int fd, CPUState *env, int 
> cpuid,
>  {
>      return x86_write_elf32_note(fd, env, cpuid, offset);
>  }
> +
> +/* This function is copied from crash */

And what does it do there and here? I suppose it is Linux-specific - any
version? This should be documented and encoded in the function name.

> +static target_ulong get_phys_base_addr(CPUState *env, target_ulong 
> *base_vaddr)
> +{
> +    int i;
> +    target_ulong kernel_base = -1;
> +    target_ulong last, mask;
> +
> +    for (i = 30, last = -1; (kernel_base == -1) && (i >= 20); i--) {
> +        mask = ~((1LL << i) - 1);
> +        *base_vaddr = env->idt.base & mask;
> +        if (*base_vaddr == last) {
> +            continue;
> +        }
> +
> +        kernel_base = cpu_get_phys_page_debug(env, *base_vaddr);
> +        last = *base_vaddr;
> +    }
> +
> +    return kernel_base;
> +}
> +
> +int cpu_add_extra_memory_mapping(MemoryMappingList *list)

Again, what does "extra" mean? Probably guest-specific, no?

> +{
> +#ifdef TARGET_X86_64
> +    target_phys_addr_t kernel_base = -1;
> +    target_ulong base_vaddr;
> +    bool lma = !!(first_cpu->hflags & HF_LMA_MASK);
> +
> +    if (!lma) {
> +        return 0;
> +    }
> +
> +    kernel_base = get_phys_base_addr(first_cpu, &base_vaddr);
> +    if (kernel_base == -1) {
> +        return -1;
> +    }
> +
> +    create_new_memory_mapping_head(list, kernel_base, base_vaddr,
> +                                   TARGET_PAGE_SIZE);
> +#endif
> +    return 0;
> +}

Jan

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