virtio: convert to use DMA api

Currently, all virtio devices bypass IOMMU completely. This is because
address_space_memory is assumed and used during DMA emulation. This
patch converts the virtio core API to use DMA API. This idea is

- introducing a new transport specific helper to query the dma address
  space. (only pci version is implemented).
- query and use this address space during virtio device guest memory
  accessing when iommu platform (VIRTIO_F_IOMMU_PLATFORM) was enabled
  for this device.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Amit Shah <amit.shah@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-block@nongnu.org
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

include/hw/virtio/virtio-access.h

@@ -17,6 +17,7 @@
 #define QEMU_VIRTIO_ACCESS_H
 
 #include "hw/virtio/virtio.h"
+#include "hw/virtio/virtio-bus.h"
 #include "exec/address-spaces.h"
 
 #if defined(TARGET_PPC64) || defined(TARGET_ARM)
@@ -40,45 +41,55 @@ static inline bool virtio_access_is_big_endian(VirtIODevice *vdev)
 
 static inline uint16_t virtio_lduw_phys(VirtIODevice *vdev, hwaddr pa)
 {
+    AddressSpace *dma_as = vdev->dma_as;
+
     if (virtio_access_is_big_endian(vdev)) {
-        return lduw_be_phys(&address_space_memory, pa);
+        return lduw_be_phys(dma_as, pa);
     }
-    return lduw_le_phys(&address_space_memory, pa);
+    return lduw_le_phys(dma_as, pa);
 }
 
 static inline uint32_t virtio_ldl_phys(VirtIODevice *vdev, hwaddr pa)
 {
+    AddressSpace *dma_as = vdev->dma_as;
+
     if (virtio_access_is_big_endian(vdev)) {
-        return ldl_be_phys(&address_space_memory, pa);
+        return ldl_be_phys(dma_as, pa);
     }
-    return ldl_le_phys(&address_space_memory, pa);
+    return ldl_le_phys(dma_as, pa);
 }
 
 static inline uint64_t virtio_ldq_phys(VirtIODevice *vdev, hwaddr pa)
 {
+    AddressSpace *dma_as = vdev->dma_as;
+
     if (virtio_access_is_big_endian(vdev)) {
-        return ldq_be_phys(&address_space_memory, pa);
+        return ldq_be_phys(dma_as, pa);
     }
-    return ldq_le_phys(&address_space_memory, pa);
+    return ldq_le_phys(dma_as, pa);
 }
 
 static inline void virtio_stw_phys(VirtIODevice *vdev, hwaddr pa,
                                    uint16_t value)
 {
+    AddressSpace *dma_as = vdev->dma_as;
+
     if (virtio_access_is_big_endian(vdev)) {
-        stw_be_phys(&address_space_memory, pa, value);
+        stw_be_phys(dma_as, pa, value);
     } else {
-        stw_le_phys(&address_space_memory, pa, value);
+        stw_le_phys(dma_as, pa, value);
     }
 }
 
 static inline void virtio_stl_phys(VirtIODevice *vdev, hwaddr pa,
                                    uint32_t value)
 {
+    AddressSpace *dma_as = vdev->dma_as;
+
     if (virtio_access_is_big_endian(vdev)) {
-        stl_be_phys(&address_space_memory, pa, value);
+        stl_be_phys(dma_as, pa, value);
     } else {
-        stl_le_phys(&address_space_memory, pa, value);
+        stl_le_phys(dma_as, pa, value);
     }
 }
 

include/hw/virtio/virtio-bus.h

@@ -88,6 +88,7 @@ typedef struct VirtioBusClass {
      * Note that changing this will break migration for this transport.
      */
     bool has_variable_vring_alignment;
+    AddressSpace *(*get_dma_as)(DeviceState *d);
 } VirtioBusClass;
 
 struct VirtioBusState {

include/hw/virtio/virtio.h

@@ -92,6 +92,7 @@ struct VirtIODevice
     char *bus_name;
     uint8_t device_endian;
     bool use_guest_notifier_mask;
+    AddressSpace *dma_as;
     QLIST_HEAD(, VirtQueue) *vector_queues;
 };
 
@@ -170,9 +171,9 @@ bool virtqueue_rewind(VirtQueue *vq, unsigned int num);
 void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
                     unsigned int len, unsigned int idx);
 
-void virtqueue_map(VirtQueueElement *elem);
+void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem);
 void *virtqueue_pop(VirtQueue *vq, size_t sz);
-void *qemu_get_virtqueue_element(QEMUFile *f, size_t sz);
+void *qemu_get_virtqueue_element(VirtIODevice *vdev, QEMUFile *f, size_t sz);
 void qemu_put_virtqueue_element(QEMUFile *f, VirtQueueElement *elem);
 int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
                           unsigned int out_bytes);
@@ -255,7 +256,9 @@ typedef struct VirtIORNGConf VirtIORNGConf;
     DEFINE_PROP_BIT64("notify_on_empty", _state, _field,  \
                       VIRTIO_F_NOTIFY_ON_EMPTY, true), \
     DEFINE_PROP_BIT64("any_layout", _state, _field, \
-                      VIRTIO_F_ANY_LAYOUT, true)
+                      VIRTIO_F_ANY_LAYOUT, true), \
+    DEFINE_PROP_BIT64("iommu_platform", _state, _field, \
+                      VIRTIO_F_IOMMU_PLATFORM, false)
 
 hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n);
 hwaddr virtio_queue_get_avail_addr(VirtIODevice *vdev, int n);