Re: [PATCH kernel v7 04/31] vfio: powerpc/spapr: Use it_page_size

[Alex Williamson]

On Sat, 2015-03-28 at 01:54 +1100, Alexey Kardashevskiy wrote:
> This makes use of the it_page_size from the iommu_table struct
> as page size can differ.
> 
> This replaces missing IOMMU_PAGE_SHIFT macro in commented debug code
> as recently introduced IOMMU_PAGE_XXX macros do not include
> IOMMU_PAGE_SHIFT.
> 
> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
> Reviewed-by: David Gibson <da...@gibson.dropbear.id.au>
> ---
>  drivers/vfio/vfio_iommu_spapr_tce.c | 26 +++++++++++++-------------
>  1 file changed, 13 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c 
> b/drivers/vfio/vfio_iommu_spapr_tce.c
> index f835e63..8bbee22 100644
> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> @@ -91,7 +91,7 @@ static int tce_iommu_enable(struct tce_container *container)
>        * enforcing the limit based on the max that the guest can map.
>        */
>       down_write(&current->mm->mmap_sem);
> -     npages = (tbl->it_size << IOMMU_PAGE_SHIFT_4K) >> PAGE_SHIFT;
> +     npages = (tbl->it_size << tbl->it_page_shift) >> PAGE_SHIFT;
>       locked = current->mm->locked_vm + npages;
>       lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
>       if (locked > lock_limit && !capable(CAP_IPC_LOCK)) {
> @@ -120,7 +120,7 @@ static void tce_iommu_disable(struct tce_container 
> *container)
>  
>       down_write(&current->mm->mmap_sem);
>       current->mm->locked_vm -= (container->tbl->it_size <<
> -                     IOMMU_PAGE_SHIFT_4K) >> PAGE_SHIFT;
> +                     container->tbl->it_page_shift) >> PAGE_SHIFT;
>       up_write(&current->mm->mmap_sem);
>  }
>  
> @@ -222,7 +222,7 @@ static long tce_iommu_build(struct tce_container 
> *container,
>                                       tce, ret);
>                       break;
>               }
> -             tce += IOMMU_PAGE_SIZE_4K;
> +             tce += IOMMU_PAGE_SIZE(tbl);


Is PAGE_SIZE ever smaller than IOMMU_PAGE_SIZE(tbl)?  IOW, can the page
we got from get_user_pages_fast() ever not completely fill the tce
entry?

(Have I asked this before?  Sorry if so)

_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev