intel-iommu: add Intel IOMMU emulation to q35 and add a machine option "iommu" as a switch

Add Intel IOMMU emulation to q35 chipset and expose it to the guest.
1. Add a machine option. Users can use "-machine iommu=on|off" in the command
line to enable/disable Intel IOMMU. The default is off.
2. Accroding to the machine option, q35 will initialize the Intel IOMMU and
use pci_setup_iommu() to setup q35_host_dma_iommu() as the IOMMU function for
the pci bus.
3. q35_host_dma_iommu() will return different address space according to the
bus_num and devfn of the device.

Signed-off-by: Le Tan <tamlokveer@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 7a66c57ab7..0708de57f6 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -235,6 +235,20 @@ static void machine_set_firmware(Object *obj, const char *value, Error **errp)
     ms->firmware = g_strdup(value);
 }
 
+static bool machine_get_iommu(Object *obj, Error **errp)
+{
+    MachineState *ms = MACHINE(obj);
+
+    return ms->iommu;
+}
+
+static void machine_set_iommu(Object *obj, bool value, Error **errp)
+{
+    MachineState *ms = MACHINE(obj);
+
+    ms->iommu = value;
+}
+
 static void machine_initfn(Object *obj)
 {
     object_property_add_str(obj, "accel",
@@ -274,6 +288,9 @@ static void machine_initfn(Object *obj)
     object_property_add_bool(obj, "usb", machine_get_usb, machine_set_usb, NULL);
     object_property_add_str(obj, "firmware",
                             machine_get_firmware, machine_set_firmware, NULL);
+    object_property_add_bool(obj, "iommu",
+                             machine_get_iommu,
+                             machine_set_iommu, NULL);
 }
 
 static void machine_finalize(Object *obj)