Re: [Xen-devel] [PATCH for-4.13 1/2] xen/arm: domain_build: Avoid implicit conversion from ULL to UL

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Sun, 29 Sep 2019, Julien Grall wrote:
> Clang 8.0 will fail to build domain_build.c on Arm32 because of the
> following error:
> 
> domain_build.c:448:21: error: implicit conversion from 'unsigned long long' 
> to 'unsigned long' changes value from 1090921693184 to 0
> [-Werror,-Wconstant-conversion]
>     bank_size = MIN(GUEST_RAM1_SIZE, kinfo->unassigned_mem);
> 
> Arm32 is able to support more than 4GB of physical memory, so it would
> be theorically possible to create domian with more the 4GB of RAM.
                                    ^ domain

Other than the typo:

Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> Therefore, the size of a bank may not fit in 32-bit.
> 
> This can be resolved by switch the variable bank_size and the parameter
> tot_size to "paddr_t".
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> 
> ---
> 
> Cc: Juergen Gross <jgross@xxxxxxxx>
> 
>     I am not aware of any users trying to allocate more than 4GB VM for
>     32-bit (there more it is in the dom0less path). Nonetheless, it
>     would be best to fix it as soon as possible.
> 
>     Only built test it.
> ---
>  xen/arch/arm/domain_build.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index 337a89e518..b791e4b512 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -377,7 +377,7 @@ static void __init allocate_memory_11(struct domain *d,
>  static bool __init allocate_bank_memory(struct domain *d,
>                                         struct kernel_info *kinfo,
>                                         gfn_t sgfn,
> -                                       unsigned long tot_size)
> +                                       paddr_t tot_size)
>  {
>      int res;
>      struct page_info *pg;
> @@ -433,7 +433,7 @@ static bool __init allocate_bank_memory(struct domain *d,
>  static void __init allocate_memory(struct domain *d, struct kernel_info 
> *kinfo)
>  {
>      unsigned int i;
> -    unsigned long bank_size;
> +    paddr_t bank_size;
>  
>      printk(XENLOG_INFO "Allocating mappings totalling %ldMB for %pd:\n",
>             /* Don't want format this as PRIpaddr (16 digit hex) */
> -- 
> 2.11.0
> 

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