Re: [Qemu-devel] [PATCH 02/12] s390: Lowcore mapping helper.

[Alexander Graf]

On 17.01.2013, at 15:23, Cornelia Huck wrote:

> Create a lowcore mapping helper that includes a check for sufficient
> length.
> 
> Signed-off-by: Cornelia Huck <address@hidden>
> ---
> target-s390x/helper.c | 31 +++++++++++++++++++++++++------
> 1 file changed, 25 insertions(+), 6 deletions(-)
> 
> diff --git a/target-s390x/helper.c b/target-s390x/helper.c
> index 9a132e6..bf2b4d3 100644
> --- a/target-s390x/helper.c
> +++ b/target-s390x/helper.c
> @@ -471,13 +471,32 @@ static uint64_t get_psw_mask(CPUS390XState *env)
>     return r;
> }
> 
> +static LowCore *cpu_map_lowcore(CPUS390XState *env, hwaddr *len)

Just declare len to PAGE_SIZE * 2, like you do in kvm. Or to sizeof(LowCore). 
Then don't pass it in as parameter, but basically guarantee that the function 
always returns a full LowCore struct.

> +{
> +    LowCore *lowcore;
> +
> +    if (*len < sizeof(LowCore)) {
> +        cpu_abort(env, "Insufficient length %d for mapping lowcore\n",
> +                  (int) *len);
> +    }
> +
> +    lowcore = cpu_physical_memory_map(env->psa, len, 1);

Here is the place where the size check should be really :).


Alex