virtio-pci: implement iommu_enabled()

This patch implements the PCI transport version of iommu_enabled. This
is done by comparing the address space returned by
pci_device_iommu_address_space() against address_space_memory.

Note that an ideal approach is to use pci_device_iommu_address_space()
in get_dma_as(), but it might not work well since the IOMMU could be
initialized after the virtio-pci device is initialized.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20210804034803.1644-3-jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 433060ac02..6e16e2705c 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1121,6 +1121,19 @@ static AddressSpace *virtio_pci_get_dma_as(DeviceState *d)
     return pci_get_address_space(dev);
 }
 
+static bool virtio_pci_iommu_enabled(DeviceState *d)
+{
+    VirtIOPCIProxy *proxy = VIRTIO_PCI(d);
+    PCIDevice *dev = &proxy->pci_dev;
+    AddressSpace *dma_as = pci_device_iommu_address_space(dev);
+
+    if (dma_as == &address_space_memory) {
+        return false;
+    }
+
+    return true;
+}
+
 static bool virtio_pci_queue_enabled(DeviceState *d, int n)
 {
     VirtIOPCIProxy *proxy = VIRTIO_PCI(d);
@@ -2202,6 +2215,7 @@ static void virtio_pci_bus_class_init(ObjectClass *klass, void *data)
     k->ioeventfd_enabled = virtio_pci_ioeventfd_enabled;
     k->ioeventfd_assign = virtio_pci_ioeventfd_assign;
     k->get_dma_as = virtio_pci_get_dma_as;
+    k->iommu_enabled = virtio_pci_iommu_enabled;
     k->queue_enabled = virtio_pci_queue_enabled;
 }