1 files changed, 67 insertions, 9 deletions

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index d2595fbd55..ab96ce1776 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -109,6 +109,29 @@ static const VMStateDescription vmstate_virtio_pci_modern_queue_state = {
     }
 };
 
+static bool virtio_pci_modern_state_features128_needed(void *opaque)
+{
+    VirtIOPCIProxy *proxy = opaque;
+    uint32_t features = 0;
+    int i;
+
+    for (i = 2; i < ARRAY_SIZE(proxy->guest_features); ++i) {
+        features |= proxy->guest_features[i];
+    }
+    return features;
+}
+
+static const VMStateDescription vmstate_virtio_pci_modern_state_features128 = {
+    .name = "virtio_pci/modern_state/features128",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = &virtio_pci_modern_state_features128_needed,
+    .fields = (const VMStateField[]) {
+        VMSTATE_UINT32_SUB_ARRAY(guest_features, VirtIOPCIProxy, 2, 2),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static bool virtio_pci_modern_state_needed(void *opaque)
 {
     VirtIOPCIProxy *proxy = opaque;
@@ -116,6 +139,12 @@ static bool virtio_pci_modern_state_needed(void *opaque)
     return virtio_pci_modern(proxy);
 }
 
+/*
+ * Avoid silently breaking migration should the feature space increase
+ * even more in the (far away) future
+ */
+QEMU_BUILD_BUG_ON(VIRTIO_FEATURES_NU32S != 4);
+
 static const VMStateDescription vmstate_virtio_pci_modern_state_sub = {
     .name = "virtio_pci/modern_state",
     .version_id = 1,
@@ -124,11 +153,15 @@ static const VMStateDescription vmstate_virtio_pci_modern_state_sub = {
     .fields = (const VMStateField[]) {
         VMSTATE_UINT32(dfselect, VirtIOPCIProxy),
         VMSTATE_UINT32(gfselect, VirtIOPCIProxy),
-        VMSTATE_UINT32_ARRAY(guest_features, VirtIOPCIProxy, 2),
+        VMSTATE_UINT32_SUB_ARRAY(guest_features, VirtIOPCIProxy, 0, 2),
         VMSTATE_STRUCT_ARRAY(vqs, VirtIOPCIProxy, VIRTIO_QUEUE_MAX, 0,
                              vmstate_virtio_pci_modern_queue_state,
                              VirtIOPCIQueue),
         VMSTATE_END_OF_LIST()
+    },
+    .subsections = (const VMStateDescription * const []) {
+        &vmstate_virtio_pci_modern_state_features128,
+        NULL
     }
 };
 
@@ -1477,6 +1510,19 @@ int virtio_pci_add_shm_cap(VirtIOPCIProxy *proxy,
     return virtio_pci_add_mem_cap(proxy, &cap.cap);
 }
 
+static int virtio_pci_select_max(const VirtIODevice *vdev)
+{
+    int i;
+
+    for (i = VIRTIO_FEATURES_NU64S - 1; i > 0; i--) {
+        if (vdev->host_features_ex[i]) {
+            return (i + 1) * 2;
+        }
+    }
+
+    return 2;
+}
+
 static uint64_t virtio_pci_common_read(void *opaque, hwaddr addr,
                                        unsigned size)
 {
@@ -1494,18 +1540,21 @@ static uint64_t virtio_pci_common_read(void *opaque, hwaddr addr,
         val = proxy->dfselect;
         break;
     case VIRTIO_PCI_COMMON_DF:
-        if (proxy->dfselect <= 1) {
+        if (proxy->dfselect < virtio_pci_select_max(vdev)) {
             VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
 
-            val = (vdev->host_features & ~vdc->legacy_features) >>
-                (32 * proxy->dfselect);
+            val = vdev->host_features_ex[proxy->dfselect >> 1] >>
+                  (32 * (proxy->dfselect & 1));
+            if (proxy->dfselect <= 1) {
+                val &= (~vdc->legacy_features) >> (32 * proxy->dfselect);
+            }
         }
         break;
     case VIRTIO_PCI_COMMON_GFSELECT:
         val = proxy->gfselect;
         break;
     case VIRTIO_PCI_COMMON_GF:
-        if (proxy->gfselect < ARRAY_SIZE(proxy->guest_features)) {
+        if (proxy->gfselect < virtio_pci_select_max(vdev)) {
             val = proxy->guest_features[proxy->gfselect];
         }
         break;
@@ -1588,11 +1637,18 @@ static void virtio_pci_common_write(void *opaque, hwaddr addr,
         proxy->gfselect = val;
         break;
     case VIRTIO_PCI_COMMON_GF:
-        if (proxy->gfselect < ARRAY_SIZE(proxy->guest_features)) {
+        if (proxy->gfselect < virtio_pci_select_max(vdev)) {
+            uint64_t features[VIRTIO_FEATURES_NU64S];
+            int i;
+
             proxy->guest_features[proxy->gfselect] = val;
-            virtio_set_features(vdev,
-                                (((uint64_t)proxy->guest_features[1]) << 32) |
-                                proxy->guest_features[0]);
+            virtio_features_clear(features);
+            for (i = 0; i < ARRAY_SIZE(proxy->guest_features); ++i) {
+                uint64_t cur = proxy->guest_features[i];
+
+                features[i >> 1] |= cur << ((i & 1) * 32);
+            }
+            virtio_set_features_ex(vdev, features);
         }
         break;
     case VIRTIO_PCI_COMMON_MSIX:
@@ -2311,6 +2367,8 @@ static void virtio_pci_reset(DeviceState *qdev)
     virtio_bus_reset(bus);
     msix_unuse_all_vectors(&proxy->pci_dev);
 
+    memset(proxy->guest_features, 0, sizeof(proxy->guest_features));
+
     for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
         proxy->vqs[i].enabled = 0;
         proxy->vqs[i].reset = 0;