On 14.09.2017 22:17, Mohammed Gamal wrote: > Starting the following command line causes a segfault > qemu-system-x86_64 -S -machine isapc,accel=kvm -device intel-iommu > > This is due to the fact that the machine type 'isapc' doesn't have > a PCI bus, while intel_iommu doesn't check if the machine has PCI support > and subsequently does a null-pointer access. Intel IOMMU shouldn't even work > if the target machine doesn't have PCI. > > Add a check for PCI on the given machine type and return an error if PCI > is not supported. > > Signed-off-by: Mohammed Gamal <mga...@redhat.com> > --- > hw/i386/intel_iommu.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c > index 3a5bb0b..fab0b4b 100644 > --- a/hw/i386/intel_iommu.c > +++ b/hw/i386/intel_iommu.c > @@ -3041,6 +3041,13 @@ static void vtd_realize(DeviceState *dev, Error **errp) > } > > bus = pcms->bus; > + > + if (!bus) { > + error_setg(errp, "Machine-type '%s' does not support PCI", > + mc->name); > + return; > + } > + > x86_iommu->type = TYPE_INTEL; > > if (!vtd_decide_config(s, errp)) { >
Patch looks basically fine to me, too, but I think I'd also rather change the "if (!pcms)" at the beginning of the function into "if (!pcms || !pcms->bus)" here to use the same error message for both cases. Thomas