On 19/04/2022 10:39, Jan Beulich wrote:
> Besides the reporter's issue of hitting a NULL deref when !CONFIG_GDBSX,
> XEN_DOMCTL_test_assign_device can legitimately end up having NULL passed
> here, when the domctl was passed DOMID_INVALID.
>
> Fixes: 71e617a6b8f6 ("use is_iommu_enabled() where appropriate...")
> Reported-by: Cheyenne Wills <[email protected]>
> Signed-off-by: Jan Beulich <[email protected]>
>
> --- a/xen/drivers/passthrough/iommu.c
> +++ b/xen/drivers/passthrough/iommu.c
> @@ -558,7 +558,7 @@ int iommu_do_domctl(
> {
> int ret = -ENODEV;
>
> - if ( !is_iommu_enabled(d) )
> + if ( !(d ? is_iommu_enabled(d) : iommu_enabled) )
> return -EOPNOTSUPP;
Having spent the better part of a day debugging this mess, this patch is
plain broken.
It depends on Juergen's "xen/iommu: cleanup iommu related domctl
handling" patch, because otherwise it erroneously fails non-IOMMU subops.
~Andrew
