Re: [Qemu-devel] [PATCH v7 7/8] exec: report error when memory < hpagesize

[Peter Crosthwaite]

On Fri, Aug 15, 2014 at 8:07 PM, Hu Tao <address@hidden> wrote:
> Report an error when memory < hpagesize in file_ram_alloc() so callers
> can handle the error.
>
> If user adds a memory-backend-file object using object_add command,
> specifying a size that is less than huge page size, qemu will core dump
> with message:
>
>   Bad ram offset fffffffffffff000
>   Aborted (core dumped)
>
> This patch fixes the problem. With this patch, qemu reports error
> message like:
>
>   qemu-system-x86_64: -object 
> memory-backend-file,mem-path=/hugepages,id=mem-file0,size=1M: memory
>   size 0x100000 must be equal to or larger than huge page size 0x200000
>
> Signed-off-by: Hu Tao <address@hidden>

Reviewed-by: Peter Crosthwaite <address@hidden>

> ---
>  exec.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/exec.c b/exec.c
> index c361752..ed59f3c 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -1024,9 +1024,9 @@ static void *file_ram_alloc(RAMBlock *block,
>      char *filename;
>      char *sanitized_name;
>      char *c;
> -    void *area;
> +    void *area = NULL;
>      int fd;
> -    unsigned long hpagesize;
> +    uint64_t hpagesize;
>
>      hpagesize = gethugepagesize(path);
>      if (!hpagesize) {
> @@ -1034,7 +1034,10 @@ static void *file_ram_alloc(RAMBlock *block,
>      }
>
>      if (memory < hpagesize) {
> -        return NULL;
> +        error_setg(errp, "memory size 0x" RAM_ADDR_FMT " must be equal to "
> +                   "or larger than huge page size 0x%" PRIx64,
> +                   memory, hpagesize);
> +        goto error;
>      }
>
>      if (kvm_enabled() && !kvm_has_sync_mmu()) {
> --
> 1.9.3
>
>