On Fri, Feb 24, 2017 at 01:21:52AM +0200, Michael S. Tsirkin wrote:
> On Wed, Feb 22, 2017 at 01:49:25PM +0800, Peter Xu wrote:
> > Intel vIOMMU devices are created with "-device" parameter, while here
> > actually we need to make sure this device will be created before some
> > other PCI devices (like vfio-pci devices) so that we know iommu_fn will
> > be setup correctly before realizations of those PCI devices.
> > Here we do explicit check to make sure intel-iommu device will be inited
> > before all the rest of the PCI devices. This is done by checking against
> > the devices dangled under current root PCIe bus and we should see
> > nothing there besides integrated ICH9 ones.
> >
> > If the user violated this rule, we abort the program.
> >
> > Maybe one day we will be able to manage the ordering of device
> > initialization, and then we can grant VT-d devices a higher init
> > priority. But before that, let's have this explicit check to make sure
> > of it.
> >
> > Signed-off-by: Peter Xu <pet...@redhat.com>
> > ---
> > hw/i386/intel_iommu.c | 40 ++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 40 insertions(+)
> >
> > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> > index 22d8226..db74124 100644
> > --- a/hw/i386/intel_iommu.c
> > +++ b/hw/i386/intel_iommu.c
> > @@ -31,6 +31,7 @@
> > #include "hw/i386/apic-msidef.h"
> > #include "hw/boards.h"
> > #include "hw/i386/x86-iommu.h"
> > +#include "hw/i386/ich9.h"
> > #include "hw/pci-host/q35.h"
> > #include "sysemu/kvm.h"
> > #include "hw/i386/apic_internal.h"
> > @@ -2560,6 +2561,41 @@ static bool vtd_decide_config(IntelIOMMUState *s,
> > Error **errp)
> > return true;
> > }
> >
> > +static bool vtd_has_inited_pci_devices(PCIBus *bus, Error **errp)
> > +{
> > + int i;
> > + uint8_t func;
> > +
> > + /* We check against root bus */
> > + assert(bus && pci_bus_is_root(bus));
> > +
> > + /*
> > + * We need to make sure vIOMMU device is created before other PCI
> > + * devices other than the integrated ICH9 ones,
>
>
> Why wouldn't this apply to integrated ICH9 ones?
Because these integrated devices are created along with q35 in
pc_q35_init() with:
pc_vga_init(isa_bus, host_bus);
pc_nic_init(isa_bus, host_bus);
which is definitely ahead of the general device init routines,
including VT-d device.
>
>
> > so that they can
> > + * get correct iommu_fn setup even during its realize(). Some
> > + * devices (e.g., vfio-pci) will need a correct iommu_fn to work.
>
> If there's something special about vfio devices, then just check
> the device type.
Yeah. I think that's the most feasible way to do this for now. If Alex
won't disagree, I can prepare a new version.
Thanks,
-- peterx
