Re: [Qemu-devel] [PATCH v5 03/11] vfio: Fix 128 bit handling

[Paolo Bonzini <pbonzini@redhat.com>]

Il 12/03/2014 06:52, Alexey Kardashevskiy ha scritto:
> Upcoming VFIO on SPAPR PPC64 support will initialize the IOMMU
> memory region with UINT64_MAX (2^64 bytes) size so int128_get64()
> will assert.
>
> The patch takes care of this check. The existing type1 IOMMU code
> is not expected to map all 64 bits of RAM so the patch does not
> touch that part.
>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
> Changes:
> v3:
> * 64bit @end is calculated from 128-bit @llend instead of repeating
> the same calculation steps
>
> v2:
> * used new function int128_exts64()
> ---
>  hw/misc/vfio.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
> index c2c688c..029a100 100644
> --- a/hw/misc/vfio.c
> +++ b/hw/misc/vfio.c
> @@ -2251,6 +2251,7 @@ static void vfio_listener_region_add(MemoryListener *listener,
>      VFIOContainer *container = container_of(listener, VFIOContainer,
>                                              iommu_data.type1.listener);
>      hwaddr iova, end;
> +    Int128 llend;
>      void *vaddr;
>      int ret;
>
> @@ -2271,13 +2272,15 @@ static void vfio_listener_region_add(MemoryListener *listener,
>      }
>
>      iova = TARGET_PAGE_ALIGN(section->offset_within_address_space);
> -    end = (section->offset_within_address_space + int128_get64(section->size)) &
> -          TARGET_PAGE_MASK;
> +    llend = int128_make64(section->offset_within_address_space);
> +    llend = int128_add(llend, section->size);
> +    llend = int128_and(llend, int128_exts64(TARGET_PAGE_MASK));
>
> -    if (iova >= end) {
> +    if (int128_ge(int128_make64(iova), llend)) {
>          return;
>      }
>
> +    end = int128_get64(llend);
>      vaddr = memory_region_get_ram_ptr(section->mr) +
>              section->offset_within_region +
>              (iova - section->offset_within_address_space);
>

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>