Hi Alex,
On 3/30/2023 1:26 PM, Alex Williamson wrote:
> On Tue, 28 Mar 2023 14:53:29 -0700
> Reinette Chatre <reinette.chatre@xxxxxxxxx> wrote:
...
>> @@ -399,7 +399,8 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_core_device *vdev,
>> static int vfio_msi_set_block(struct vfio_pci_core_device *vdev, unsigned start,
>> unsigned count, int32_t *fds, bool msix)
>> {
>> - int i, j, ret = 0;
>> + int i, ret = 0;
>> + unsigned int j;
>>
>> if (start >= vdev->num_ctx || start + count > vdev->num_ctx)
>> return -EINVAL;
>
> Unfortunately this turns the unwind portion of the function into an
> infinite loop in the common case when @start is zero:
>
> for (--j; j >= (int)start; j--)
> vfio_msi_set_vector_signal(vdev, j, -1, msix);
>
>
Thank you very much for catching this. It is not clear to me how you
would prefer to resolve this. Would you prefer that the vector parameter
in vfio_msi_set_vector_signal() continue to be an int and this patch be
dropped and the "if (vector < 0)" check remains (option A)? Or, alternatively,
I see two other possible solutions where the vector parameter in
vfio_msi_set_vector_signal() becomes an unsigned int and the above snippet
could be one of:
option B:
vfio_msi_set_block()
{
int i, j, ret = 0;
...
for (--j; j >= (int)start; j--)
vfio_msi_set_vector_signal(vdev, (unsigned int)j, -1, msix);
}
option C:
vfio_msi_set_block()
{
int i, ret = 0;
unsigned int j;
...
for (--j; j >= start && j < start + count; j--)
vfio_msi_set_vector_signal(vdev, j, -1, msix);
}
What would you prefer?
Reinette
