Re: [Qemu-devel] [PATCH] vfio-pci: Fix BAR size overflow

[Don Slutz]

On 01/06/15 19:03, Alex Williamson wrote:
> We use an unsigned int when working with the PCI BAR size, which can
> obviously overflow if the BAR is 4GB or larger.  This needs to change
> to an unsigned long.  A similar issue is possible, though even more
> unlikely, when mapping the region above an MSI-X table.  The start of
> the table must be below 4GB, but the end, and therefore the start of
> the next mapping region, could still land at 4GB.
>
> Suggested-by: Nishank Trivedi <address@hidden>
> Signed-off-by: Alex Williamson <address@hidden>
> ---
>
>   hw/vfio/pci.c |    4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index b4e73d1..03790a8 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -2301,7 +2301,7 @@ static void vfio_unmap_bar(VFIOPCIDevice *vdev, int nr)
>   static void vfio_map_bar(VFIOPCIDevice *vdev, int nr)
>   {
>       VFIOBAR *bar = &vdev->bars[nr];
> -    unsigned size = bar->region.size;
> +    unsigned long size = bar->region.size;

On a 32bit build, this does not fix the issue.
    -Don Slutz

>       char name[64];
>       uint32_t pci_bar;
>       uint8_t type;
> @@ -2351,7 +2351,7 @@ static void vfio_map_bar(VFIOPCIDevice *vdev, int nr)
>       }
>   
>       if (vdev->msix && vdev->msix->table_bar == nr) {
> -        unsigned start;
> +        unsigned long start;
>   
>           start = HOST_PAGE_ALIGN(vdev->msix->table_offset +
>                                   (vdev->msix->entries * PCI_MSIX_ENTRY_SIZE));