Re: [Qemu-devel] [PATCH 1/4] s390x/pci: fixup trap_msix()

[Cornelia Huck <cohuck@redhat.com>]

On Mon, 28 Aug 2017 10:04:44 +0200
Yi Min Zhao <zyimin@linux.vnet.ibm.com> wrote:

> The function trap_msix() is to check if pcistg instruction would access
> msix table entries. The correct boundary condition should be
> [table_offset, table_offset+entries*entry_size). But the current
> condition calculated misses the last entry. So let's fixup it.
> 
> Acked-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
> Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
> Signed-off-by: Yi Min Zhao <zyimin@linux.vnet.ibm.com>
> ---
>  hw/s390x/s390-pci-inst.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
> index b7beb8c36a..eba9ffb5f2 100644
> --- a/hw/s390x/s390-pci-inst.c
> +++ b/hw/s390x/s390-pci-inst.c
> @@ -440,8 +440,8 @@ static int trap_msix(S390PCIBusDevice *pbdev, uint64_t offset, uint8_t pcias)
>  {
>      if (pbdev->msix.available && pbdev->msix.table_bar == pcias &&
>          offset >= pbdev->msix.table_offset &&
> -        offset <= pbdev->msix.table_offset +
> -                  (pbdev->msix.entries - 1) * PCI_MSIX_ENTRY_SIZE) {
> +        offset < (pbdev->msix.table_offset +
> +                  pbdev->msix.entries * PCI_MSIX_ENTRY_SIZE)) {
>          return 1;
>      } else {
>          return 0;

What happened before due to the miscalculation? Write to wrong memory
region?