[PATCH 2/3] intel-iommu: fail DEVIOTLB_UNMAP without dt mode

[Jason Wang <jasowang@redhat.com>]

Without dt mode, device IOTLB notifier won't work since guest won't
send device IOTLB invalidation descriptor in this case. Let's fail
early instead of misbehaving silently.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/i386/intel_iommu.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 9143376677..d025ef2873 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -3179,6 +3179,7 @@ static int vtd_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu,
 {
     VTDAddressSpace *vtd_as = container_of(iommu, VTDAddressSpace, iommu);
     IntelIOMMUState *s = vtd_as->iommu_state;
+    X86IOMMUState *x86_iommu = X86_IOMMU_DEVICE(s);
 
     /* TODO: add support for VFIO and vhost users */
     if (s->snoop_control) {
@@ -3193,6 +3194,13 @@ static int vtd_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu,
                          PCI_FUNC(vtd_as->devfn));
         return -ENOTSUP;
     }
+    if (!x86_iommu->dt_supported && (new & IOMMU_NOTIFIER_DEVIOTLB_UNMAP)) {
+        error_setg_errno(errp, ENOTSUP,
+                         "device %02x.%02x.%x requires device IOTLB mode",
+                         pci_bus_num(vtd_as->bus), PCI_SLOT(vtd_as->devfn),
+                         PCI_FUNC(vtd_as->devfn));
+        return -ENOTSUP;
+    }
 
     /* Update per-address-space notifier flags */
     vtd_as->notifier_flags = new;
-- 
2.25.1