Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging

pc,vhost,virtio fixes, enhancements

virtio bi-endian support
new command to resync RTC
misc bugfixes and cleanups

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

# gpg: Signature made Sun 29 Jun 2014 17:41:13 BST using RSA key ID D28D5469
# gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>"
# gpg:                 aka "Michael S. Tsirkin <mst@redhat.com>"

* remotes/mst/tags/for_upstream: (37 commits)
  tests: add human format test for string output visitor
  vhost-net: disable when cross-endian
  target-ppc: enable virtio endian ambivalent support
  virtio-9p: use virtio wrappers to access headers
  virtio-serial-bus: use virtio wrappers to access headers
  virtio-scsi: use virtio wrappers to access headers
  virtio-blk: use virtio wrappers to access headers
  virtio-balloon: use virtio wrappers to access page frame numbers
  virtio-net: use virtio wrappers to access headers
  virtio: allow byte swapping for vring
  virtio: memory accessors for endian-ambivalent targets
  virtio: add endian-ambivalent support to VirtIODevice
  cpu: introduce CPUClass::virtio_is_big_endian()
  exec: introduce target_words_bigendian() helper
  virtio: add subsections to the migration stream
  virtio-rng: implement per-device migration calls
  virtio-balloon: implement per-device migration calls
  virtio-serial: implement per-device migration calls
  virtio-blk: implement per-device migration calls
  virtio-net: implement per-device migration calls
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

5 files changed, 218 insertions, 93 deletions

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 0df6a936a0..38e580642f 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -14,6 +14,7 @@
 #include "sysemu/kvm.h"
 #include "qemu/error-report.h"
 #include "qemu/sockets.h"
+#include "exec/ram_addr.h"
 
 #include <fcntl.h>
 #include <unistd.h>
@@ -47,6 +48,7 @@ typedef struct VhostUserMemoryRegion {
     uint64_t guest_phys_addr;
     uint64_t memory_size;
     uint64_t userspace_addr;
+    uint64_t mmap_offset;
 } VhostUserMemoryRegion;
 
 typedef struct VhostUserMemory {
@@ -183,10 +185,10 @@ static int vhost_user_call(struct vhost_dev *dev, unsigned long int request,
 {
     VhostUserMsg msg;
     VhostUserRequest msg_request;
-    RAMBlock *block = 0;
     struct vhost_vring_file *file = 0;
     int need_reply = 0;
     int fds[VHOST_MEMORY_MAX_NREGIONS];
+    int i, fd;
     size_t fd_num = 0;
 
     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
@@ -212,14 +214,17 @@ static int vhost_user_call(struct vhost_dev *dev, unsigned long int request,
         break;
 
     case VHOST_SET_MEM_TABLE:
-        QTAILQ_FOREACH(block, &ram_list.blocks, next)
-        {
-            if (block->fd > 0) {
-                msg.memory.regions[fd_num].userspace_addr =
-                    (uintptr_t) block->host;
-                msg.memory.regions[fd_num].memory_size = block->length;
-                msg.memory.regions[fd_num].guest_phys_addr = block->offset;
-                fds[fd_num++] = block->fd;
+        for (i = 0; i < dev->mem->nregions; ++i) {
+            struct vhost_memory_region *reg = dev->mem->regions + i;
+            fd = qemu_get_ram_fd(reg->guest_phys_addr);
+            if (fd > 0) {
+                msg.memory.regions[fd_num].userspace_addr = reg->userspace_addr;
+                msg.memory.regions[fd_num].memory_size  = reg->memory_size;
+                msg.memory.regions[fd_num].guest_phys_addr = reg->guest_phys_addr;
+                msg.memory.regions[fd_num].mmap_offset = reg->userspace_addr -
+                    (uintptr_t) qemu_get_ram_block_host_ptr(reg->guest_phys_addr);
+                assert(fd_num < VHOST_MEMORY_MAX_NREGIONS);
+                fds[fd_num++] = fd;
             }
         }
 
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index 2a2e58a297..2c30b3d8bd 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -31,6 +31,7 @@
 #endif
 
 #include "hw/virtio/virtio-bus.h"
+#include "hw/virtio/virtio-access.h"
 
 static void balloon_page(void *addr, int deflate)
 {
@@ -206,8 +207,9 @@ static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
         while (iov_to_buf(elem.out_sg, elem.out_num, offset, &pfn, 4) == 4) {
             ram_addr_t pa;
             ram_addr_t addr;
+            int p = virtio_ldl_p(vdev, &pfn);
 
-            pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT;
+            pa = (ram_addr_t) p << VIRTIO_BALLOON_PFN_SHIFT;
             offset += 4;
 
             /* FIXME: remove get_system_memory(), but how? */
@@ -248,8 +250,8 @@ static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
 
     while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
            == sizeof(stat)) {
-        uint16_t tag = tswap16(stat.tag);
-        uint64_t val = tswap64(stat.val);
+        uint16_t tag = virtio_tswap16(vdev, stat.tag);
+        uint64_t val = virtio_tswap64(vdev, stat.val);
 
         offset += sizeof(stat);
         if (tag < VIRTIO_BALLOON_S_NR)
@@ -325,10 +327,12 @@ static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 
 static void virtio_balloon_save(QEMUFile *f, void *opaque)
 {
-    VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
-    VirtIODevice *vdev = VIRTIO_DEVICE(s);
+    virtio_save(VIRTIO_DEVICE(opaque), f);
+}
 
-    virtio_save(vdev, f);
+static void virtio_balloon_save_device(VirtIODevice *vdev, QEMUFile *f)
+{
+    VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 
     qemu_put_be32(f, s->num_pages);
     qemu_put_be32(f, s->actual);
@@ -336,17 +340,16 @@ static void virtio_balloon_save(QEMUFile *f, void *opaque)
 
 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
 {
-    VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
-    VirtIODevice *vdev = VIRTIO_DEVICE(s);
-    int ret;
-
     if (version_id != 1)
         return -EINVAL;
 
-    ret = virtio_load(vdev, f);
-    if (ret) {
-        return ret;
-    }
+    return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
+}
+
+static int virtio_balloon_load_device(VirtIODevice *vdev, QEMUFile *f,
+                                      int version_id)
+{
+    VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 
     s->num_pages = qemu_get_be32(f);
     s->actual = qemu_get_be32(f);
@@ -416,6 +419,8 @@ static void virtio_balloon_class_init(ObjectClass *klass, void *data)
     vdc->get_config = virtio_balloon_get_config;
     vdc->set_config = virtio_balloon_set_config;
     vdc->get_features = virtio_balloon_get_features;
+    vdc->save = virtio_balloon_save_device;
+    vdc->load = virtio_balloon_load_device;
 }
 
 static const TypeInfo virtio_balloon_info = {
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 57e1e6141e..317324f23d 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -89,9 +89,6 @@
 /* Flags track per-device state like workarounds for quirks in older guests. */
 #define VIRTIO_PCI_FLAG_BUS_MASTER_BUG  (1 << 0)
 
-/* HACK for virtio to determine if it's running a big endian guest */
-bool virtio_is_big_endian(void);
-
 static void virtio_pci_bus_new(VirtioBusState *bus, size_t bus_size,
                                VirtIOPCIProxy *dev);
 
@@ -409,13 +406,13 @@ static uint64_t virtio_pci_config_read(void *opaque, hwaddr addr,
         break;
     case 2:
         val = virtio_config_readw(vdev, addr);
-        if (virtio_is_big_endian()) {
+        if (virtio_is_big_endian(vdev)) {
             val = bswap16(val);
         }
         break;
     case 4:
         val = virtio_config_readl(vdev, addr);
-        if (virtio_is_big_endian()) {
+        if (virtio_is_big_endian(vdev)) {
             val = bswap32(val);
         }
         break;
@@ -443,13 +440,13 @@ static void virtio_pci_config_write(void *opaque, hwaddr addr,
         virtio_config_writeb(vdev, addr, val);
         break;
     case 2:
-        if (virtio_is_big_endian()) {
+        if (virtio_is_big_endian(vdev)) {
             val = bswap16(val);
         }
         virtio_config_writew(vdev, addr, val);
         break;
     case 4:
-        if (virtio_is_big_endian()) {
+        if (virtio_is_big_endian(vdev)) {
             val = bswap32(val);
         }
         virtio_config_writel(vdev, addr, val);
diff --git a/hw/virtio/virtio-rng.c b/hw/virtio/virtio-rng.c
index b6ab3610cb..1356aca8d6 100644
--- a/hw/virtio/virtio-rng.c
+++ b/hw/virtio/virtio-rng.c
@@ -107,19 +107,20 @@ static void virtio_rng_save(QEMUFile *f, void *opaque)
 
 static int virtio_rng_load(QEMUFile *f, void *opaque, int version_id)
 {
-    VirtIORNG *vrng = opaque;
-    VirtIODevice *vdev = VIRTIO_DEVICE(vrng);
-
     if (version_id != 1) {
         return -EINVAL;
     }
-    virtio_load(vdev, f);
+    return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
+}
 
+static int virtio_rng_load_device(VirtIODevice *vdev, QEMUFile *f,
+                                  int version_id)
+{
     /* We may have an element ready but couldn't process it due to a quota
      * limit.  Make sure to try again after live migration when the quota may
      * have been reset.
      */
-    virtio_rng_process(vrng);
+    virtio_rng_process(VIRTIO_RNG(vdev));
 
     return 0;
 }
@@ -219,6 +220,7 @@ static void virtio_rng_class_init(ObjectClass *klass, void *data)
     vdc->realize = virtio_rng_device_realize;
     vdc->unrealize = virtio_rng_device_unrealize;
     vdc->get_features = get_features;
+    vdc->load = virtio_rng_load_device;
 }
 
 static void virtio_rng_initfn(Object *obj)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index a3082d569d..5c981801f3 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -19,6 +19,8 @@
 #include "hw/virtio/virtio.h"
 #include "qemu/atomic.h"
 #include "hw/virtio/virtio-bus.h"
+#include "migration/migration.h"
+#include "hw/virtio/virtio-access.h"
 
 /*
  * The alignment to use between consumer and producer parts of vring.
@@ -101,53 +103,56 @@ static void virtqueue_init(VirtQueue *vq)
                                  vq->vring.align);
 }
 
-static inline uint64_t vring_desc_addr(hwaddr desc_pa, int i)
+static inline uint64_t vring_desc_addr(VirtIODevice *vdev, hwaddr desc_pa,
+                                       int i)
 {
     hwaddr pa;
     pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, addr);
-    return ldq_phys(&address_space_memory, pa);
+    return virtio_ldq_phys(vdev, pa);
 }
 
-static inline uint32_t vring_desc_len(hwaddr desc_pa, int i)
+static inline uint32_t vring_desc_len(VirtIODevice *vdev, hwaddr desc_pa, int i)
 {
     hwaddr pa;
     pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, len);
-    return ldl_phys(&address_space_memory, pa);
+    return virtio_ldl_phys(vdev, pa);
 }
 
-static inline uint16_t vring_desc_flags(hwaddr desc_pa, int i)
+static inline uint16_t vring_desc_flags(VirtIODevice *vdev, hwaddr desc_pa,
+                                        int i)
 {
     hwaddr pa;
     pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, flags);
-    return lduw_phys(&address_space_memory, pa);
+    return virtio_lduw_phys(vdev, pa);
 }
 
-static inline uint16_t vring_desc_next(hwaddr desc_pa, int i)
+static inline uint16_t vring_desc_next(VirtIODevice *vdev, hwaddr desc_pa,
+                                       int i)
 {
     hwaddr pa;
     pa = desc_pa + sizeof(VRingDesc) * i + offsetof(VRingDesc, next);
-    return lduw_phys(&address_space_memory, pa);
+    return virtio_lduw_phys(vdev, pa);
 }
 
 static inline uint16_t vring_avail_flags(VirtQueue *vq)
 {
     hwaddr pa;
     pa = vq->vring.avail + offsetof(VRingAvail, flags);
-    return lduw_phys(&address_space_memory, pa);
+    return virtio_lduw_phys(vq->vdev, pa);
 }
 
 static inline uint16_t vring_avail_idx(VirtQueue *vq)
 {
     hwaddr pa;
     pa = vq->vring.avail + offsetof(VRingAvail, idx);
-    return lduw_phys(&address_space_memory, pa);
+    return virtio_lduw_phys(vq->vdev, pa);
 }
 
 static inline uint16_t vring_avail_ring(VirtQueue *vq, int i)
 {
     hwaddr pa;
     pa = vq->vring.avail + offsetof(VRingAvail, ring[i]);
-    return lduw_phys(&address_space_memory, pa);
+    return virtio_lduw_phys(vq->vdev, pa);
 }
 
 static inline uint16_t vring_used_event(VirtQueue *vq)
@@ -159,44 +164,44 @@ static inline void vring_used_ring_id(VirtQueue *vq, int i, uint32_t val)
 {
     hwaddr pa;
     pa = vq->vring.used + offsetof(VRingUsed, ring[i].id);
-    stl_phys(&address_space_memory, pa, val);
+    virtio_stl_phys(vq->vdev, pa, val);
 }
 
 static inline void vring_used_ring_len(VirtQueue *vq, int i, uint32_t val)
 {
     hwaddr pa;
     pa = vq->vring.used + offsetof(VRingUsed, ring[i].len);
-    stl_phys(&address_space_memory, pa, val);
+    virtio_stl_phys(vq->vdev, pa, val);
 }
 
 static uint16_t vring_used_idx(VirtQueue *vq)
 {
     hwaddr pa;
     pa = vq->vring.used + offsetof(VRingUsed, idx);
-    return lduw_phys(&address_space_memory, pa);
+    return virtio_lduw_phys(vq->vdev, pa);
 }
 
 static inline void vring_used_idx_set(VirtQueue *vq, uint16_t val)
 {
     hwaddr pa;
     pa = vq->vring.used + offsetof(VRingUsed, idx);
-    stw_phys(&address_space_memory, pa, val);
+    virtio_stw_phys(vq->vdev, pa, val);
 }
 
 static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask)
 {
+    VirtIODevice *vdev = vq->vdev;
     hwaddr pa;
     pa = vq->vring.used + offsetof(VRingUsed, flags);
-    stw_phys(&address_space_memory,
-             pa, lduw_phys(&address_space_memory, pa) | mask);
+    virtio_stw_phys(vdev, pa, virtio_lduw_phys(vdev, pa) | mask);
 }
 
 static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask)
 {
+    VirtIODevice *vdev = vq->vdev;
     hwaddr pa;
     pa = vq->vring.used + offsetof(VRingUsed, flags);
-    stw_phys(&address_space_memory,
-             pa, lduw_phys(&address_space_memory, pa) & ~mask);
+    virtio_stw_phys(vdev, pa, virtio_lduw_phys(vdev, pa) & ~mask);
 }
 
 static inline void vring_avail_event(VirtQueue *vq, uint16_t val)
@@ -206,7 +211,7 @@ static inline void vring_avail_event(VirtQueue *vq, uint16_t val)
         return;
     }
     pa = vq->vring.used + offsetof(VRingUsed, ring[vq->vring.num]);
-    stw_phys(&address_space_memory, pa, val);
+    virtio_stw_phys(vq->vdev, pa, val);
 }
 
 void virtio_queue_set_notification(VirtQueue *vq, int enable)
@@ -323,17 +328,18 @@ static unsigned int virtqueue_get_head(VirtQueue *vq, unsigned int idx)
     return head;
 }
 
-static unsigned virtqueue_next_desc(hwaddr desc_pa,
+static unsigned virtqueue_next_desc(VirtIODevice *vdev, hwaddr desc_pa,
                                     unsigned int i, unsigned int max)
 {
     unsigned int next;
 
     /* If this descriptor says it doesn't chain, we're done. */
-    if (!(vring_desc_flags(desc_pa, i) & VRING_DESC_F_NEXT))
+    if (!(vring_desc_flags(vdev, desc_pa, i) & VRING_DESC_F_NEXT)) {
         return max;
+    }
 
     /* Check they're not leading us off end of descriptors. */
-    next = vring_desc_next(desc_pa, i);
+    next = vring_desc_next(vdev, desc_pa, i);
     /* Make sure compiler knows to grab that: we don't want it changing! */
     smp_wmb();
 
@@ -356,6 +362,7 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
 
     total_bufs = in_total = out_total = 0;
     while (virtqueue_num_heads(vq, idx)) {
+        VirtIODevice *vdev = vq->vdev;
         unsigned int max, num_bufs, indirect = 0;
         hwaddr desc_pa;
         int i;
@@ -365,8 +372,8 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
         i = virtqueue_get_head(vq, idx++);
         desc_pa = vq->vring.desc;
 
-        if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_INDIRECT) {
-            if (vring_desc_len(desc_pa, i) % sizeof(VRingDesc)) {
+        if (vring_desc_flags(vdev, desc_pa, i) & VRING_DESC_F_INDIRECT) {
+            if (vring_desc_len(vdev, desc_pa, i) % sizeof(VRingDesc)) {
                 error_report("Invalid size for indirect buffer table");
                 exit(1);
             }
@@ -379,8 +386,8 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
 
             /* loop over the indirect descriptor table */
             indirect = 1;
-            max = vring_desc_len(desc_pa, i) / sizeof(VRingDesc);
-            desc_pa = vring_desc_addr(desc_pa, i);
+            max = vring_desc_len(vdev, desc_pa, i) / sizeof(VRingDesc);
+            desc_pa = vring_desc_addr(vdev, desc_pa, i);
             num_bufs = i = 0;
         }
 
@@ -391,15 +398,15 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
                 exit(1);
             }
 
-            if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_WRITE) {
-                in_total += vring_desc_len(desc_pa, i);
+            if (vring_desc_flags(vdev, desc_pa, i) & VRING_DESC_F_WRITE) {
+                in_total += vring_desc_len(vdev, desc_pa, i);
             } else {
-                out_total += vring_desc_len(desc_pa, i);
+                out_total += vring_desc_len(vdev, desc_pa, i);
             }
             if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
                 goto done;
             }
-        } while ((i = virtqueue_next_desc(desc_pa, i, max)) != max);
+        } while ((i = virtqueue_next_desc(vdev, desc_pa, i, max)) != max);
 
         if (!indirect)
             total_bufs = num_bufs;
@@ -450,6 +457,7 @@ int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
 {
     unsigned int i, head, max;
     hwaddr desc_pa = vq->vring.desc;
+    VirtIODevice *vdev = vq->vdev;
 
     if (!virtqueue_num_heads(vq, vq->last_avail_idx))
         return 0;
@@ -460,19 +468,19 @@ int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
     max = vq->vring.num;
 
     i = head = virtqueue_get_head(vq, vq->last_avail_idx++);
-    if (vq->vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
+    if (vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
         vring_avail_event(vq, vring_avail_idx(vq));
     }
 
-    if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_INDIRECT) {
-        if (vring_desc_len(desc_pa, i) % sizeof(VRingDesc)) {
+    if (vring_desc_flags(vdev, desc_pa, i) & VRING_DESC_F_INDIRECT) {
+        if (vring_desc_len(vdev, desc_pa, i) % sizeof(VRingDesc)) {
             error_report("Invalid size for indirect buffer table");
             exit(1);
         }
 
         /* loop over the indirect descriptor table */
-        max = vring_desc_len(desc_pa, i) / sizeof(VRingDesc);
-        desc_pa = vring_desc_addr(desc_pa, i);
+        max = vring_desc_len(vdev, desc_pa, i) / sizeof(VRingDesc);
+        desc_pa = vring_desc_addr(vdev, desc_pa, i);
         i = 0;
     }
 
@@ -480,30 +488,30 @@ int virtqueue_pop(VirtQueue *vq, VirtQueueElement *elem)
     do {
         struct iovec *sg;
 
-        if (vring_desc_flags(desc_pa, i) & VRING_DESC_F_WRITE) {
+        if (vring_desc_flags(vdev, desc_pa, i) & VRING_DESC_F_WRITE) {
             if (elem->in_num >= ARRAY_SIZE(elem->in_sg)) {
                 error_report("Too many write descriptors in indirect table");
                 exit(1);
             }
-            elem->in_addr[elem->in_num] = vring_desc_addr(desc_pa, i);
+            elem->in_addr[elem->in_num] = vring_desc_addr(vdev, desc_pa, i);
             sg = &elem->in_sg[elem->in_num++];
         } else {
             if (elem->out_num >= ARRAY_SIZE(elem->out_sg)) {
                 error_report("Too many read descriptors in indirect table");
                 exit(1);
             }
-            elem->out_addr[elem->out_num] = vring_desc_addr(desc_pa, i);
+            elem->out_addr[elem->out_num] = vring_desc_addr(vdev, desc_pa, i);
             sg = &elem->out_sg[elem->out_num++];
         }
 
-        sg->iov_len = vring_desc_len(desc_pa, i);
+        sg->iov_len = vring_desc_len(vdev, desc_pa, i);
 
         /* If we've got too many, that implies a descriptor loop. */
         if ((elem->in_num + elem->out_num) > max) {
             error_report("Looped descriptor");
             exit(1);
         }
-    } while ((i = virtqueue_next_desc(desc_pa, i, max)) != max);
+    } while ((i = virtqueue_next_desc(vdev, desc_pa, i, max)) != max);
 
     /* Now map what we have collected */
     virtqueue_map_sg(elem->in_sg, elem->in_addr, elem->in_num, 1);
@@ -544,6 +552,27 @@ void virtio_set_status(VirtIODevice *vdev, uint8_t val)
     vdev->status = val;
 }
 
+bool target_words_bigendian(void);
+static enum virtio_device_endian virtio_default_endian(void)
+{
+    if (target_words_bigendian()) {
+        return VIRTIO_DEVICE_ENDIAN_BIG;
+    } else {
+        return VIRTIO_DEVICE_ENDIAN_LITTLE;
+    }
+}
+
+static enum virtio_device_endian virtio_current_cpu_endian(void)
+{
+    CPUClass *cc = CPU_GET_CLASS(current_cpu);
+
+    if (cc->virtio_is_big_endian(current_cpu)) {
+        return VIRTIO_DEVICE_ENDIAN_BIG;
+    } else {
+        return VIRTIO_DEVICE_ENDIAN_LITTLE;
+    }
+}
+
 void virtio_reset(void *opaque)
 {
     VirtIODevice *vdev = opaque;
@@ -551,6 +580,13 @@ void virtio_reset(void *opaque)
     int i;
 
     virtio_set_status(vdev, 0);
+    if (current_cpu) {
+        /* Guest initiated reset */
+        vdev->device_endian = virtio_current_cpu_endian();
+    } else {
+        /* System reset */
+        vdev->device_endian = virtio_default_endian();
+    }
 
     if (k->reset) {
         k->reset(vdev);
@@ -839,10 +875,46 @@ void virtio_notify_config(VirtIODevice *vdev)
     virtio_notify_vector(vdev, vdev->config_vector);
 }
 
+static bool virtio_device_endian_needed(void *opaque)
+{
+    VirtIODevice *vdev = opaque;
+
+    assert(vdev->device_endian != VIRTIO_DEVICE_ENDIAN_UNKNOWN);
+    return vdev->device_endian != virtio_default_endian();
+}
+
+static const VMStateDescription vmstate_virtio_device_endian = {
+    .name = "virtio/device_endian",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT8(device_endian, VirtIODevice),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription vmstate_virtio = {
+    .name = "virtio",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_END_OF_LIST()
+    },
+    .subsections = (VMStateSubsection[]) {
+        {
+            .vmsd = &vmstate_virtio_device_endian,
+            .needed = &virtio_device_endian_needed
+        },
+        { 0 }
+    }
+};
+
 void virtio_save(VirtIODevice *vdev, QEMUFile *f)
 {
     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
     int i;
 
     if (k->save_config) {
@@ -877,6 +949,13 @@ void virtio_save(VirtIODevice *vdev, QEMUFile *f)
             k->save_queue(qbus->parent, i, f);
         }
     }
+
+    if (vdc->save != NULL) {
+        vdc->save(vdev, f);
+    }
+
+    /* Subsections */
+    vmstate_save_state(f, &vmstate_virtio, vdev);
 }
 
 int virtio_set_features(VirtIODevice *vdev, uint32_t val)
@@ -895,7 +974,7 @@ int virtio_set_features(VirtIODevice *vdev, uint32_t val)
     return bad ? -1 : 0;
 }
 
-int virtio_load(VirtIODevice *vdev, QEMUFile *f)
+int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
 {
     int i, ret;
     int32_t config_len;
@@ -904,6 +983,13 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f)
     uint32_t supported_features;
     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
+
+    /*
+     * We poison the endianness to ensure it does not get used before
+     * subsections have been loaded.
+     */
+    vdev->device_endian = VIRTIO_DEVICE_ENDIAN_UNKNOWN;
 
     if (k->load_config) {
         ret = k->load_config(qbus->parent, f);
@@ -926,12 +1012,18 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f)
         return -1;
     }
     config_len = qemu_get_be32(f);
-    if (config_len != vdev->config_len) {
-        error_report("Unexpected config length 0x%x. Expected 0x%zx",
-                     config_len, vdev->config_len);
-        return -1;
+
+    /*
+     * There are cases where the incoming config can be bigger or smaller
+     * than what we have; so load what we have space for, and skip
+     * any excess that's in the stream.
+     */
+    qemu_get_buffer(f, vdev->config, MIN(config_len, vdev->config_len));
+
+    while (config_len > vdev->config_len) {
+        qemu_get_byte(f);
+        config_len--;
     }
-    qemu_get_buffer(f, vdev->config, vdev->config_len);
 
     num = qemu_get_be32(f);
 
@@ -951,18 +1043,7 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f)
         vdev->vq[i].notification = true;
 
         if (vdev->vq[i].pa) {
-            uint16_t nheads;
             virtqueue_init(&vdev->vq[i]);
-            nheads = vring_avail_idx(&vdev->vq[i]) - vdev->vq[i].last_avail_idx;
-            /* Check it isn't doing very strange things with descriptor numbers. */
-            if (nheads > vdev->vq[i].vring.num) {
-                error_report("VQ %d size 0x%x Guest index 0x%x "
-                             "inconsistent with Host index 0x%x: delta 0x%x",
-                             i, vdev->vq[i].vring.num,
-                             vring_avail_idx(&vdev->vq[i]),
-                             vdev->vq[i].last_avail_idx, nheads);
-                return -1;
-            }
         } else if (vdev->vq[i].last_avail_idx) {
             error_report("VQ %d address 0x0 "
                          "inconsistent with Host index 0x%x",
@@ -977,6 +1058,40 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f)
     }
 
     virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
+
+    if (vdc->load != NULL) {
+        ret = vdc->load(vdev, f, version_id);
+        if (ret) {
+            return ret;
+        }
+    }
+
+    /* Subsections */
+    ret = vmstate_load_state(f, &vmstate_virtio, vdev, 1);
+    if (ret) {
+        return ret;
+    }
+
+    if (vdev->device_endian == VIRTIO_DEVICE_ENDIAN_UNKNOWN) {
+        vdev->device_endian = virtio_default_endian();
+    }
+
+    for (i = 0; i < num; i++) {
+        if (vdev->vq[i].pa) {
+            uint16_t nheads;
+            nheads = vring_avail_idx(&vdev->vq[i]) - vdev->vq[i].last_avail_idx;
+            /* Check it isn't doing strange things with descriptor numbers. */
+            if (nheads > vdev->vq[i].vring.num) {
+                error_report("VQ %d size 0x%x Guest index 0x%x "
+                             "inconsistent with Host index 0x%x: delta 0x%x",
+                             i, vdev->vq[i].vring.num,
+                             vring_avail_idx(&vdev->vq[i]),
+                             vdev->vq[i].last_avail_idx, nheads);
+                return -1;
+            }
+        }
+    }
+
     return 0;
 }
 
@@ -1034,6 +1149,7 @@ void virtio_init(VirtIODevice *vdev, const char *name,
     }
     vdev->vmstate = qemu_add_vm_change_state_handler(virtio_vmstate_change,
                                                      vdev);
+    vdev->device_endian = virtio_default_endian();
 }
 
 hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n)