Re: [PATCH] msi: fix MSI vector limit check in msi_set_mask()

[Stefan Hajnoczi]

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

On Thu, 23 Jun 2022 at 16:42, Jagannathan Raman <jag.raman@oracle.com> wrote:
>
> MSI supports a maximum of PCI_MSI_VECTORS_MAX vectors - from 0 to
> PCI_MSI_VECTORS_MAX - 1.
>
> msi_set_mask() was previously using PCI_MSI_VECTORS_MAX as the upper
> limit for MSI vectors. Fix the upper limit to PCI_MSI_VECTORS_MAX - 1.
>
> Fixes: Coverity CID 1490141
> Fixes: 08cf3dc61199 vfio-user: handle device interrupts
>
> Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
> ---
>  hw/pci/msi.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/hw/pci/msi.c b/hw/pci/msi.c
> index 5c471b9616..058d1d1ef1 100644
> --- a/hw/pci/msi.c
> +++ b/hw/pci/msi.c
> @@ -322,9 +322,9 @@ void msi_set_mask(PCIDevice *dev, int vector, bool mask, 
> Error **errp)
>      bool msi64bit = flags & PCI_MSI_FLAGS_64BIT;
>      uint32_t irq_state, vector_mask, pending;
>
> -    if (vector > PCI_MSI_VECTORS_MAX) {
> +    if (vector >= PCI_MSI_VECTORS_MAX) {
>          error_setg(errp, "msi: vector %d not allocated. max vector is %d",
> -                   vector, PCI_MSI_VECTORS_MAX);
> +                   vector, (PCI_MSI_VECTORS_MAX - 1));
>          return;
>      }
>
> --
> 2.20.1
>
>