virtio,vhost: fixes

Add a feature flag for new protocol messages.
 Misc fixes.
 
 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging

virtio,vhost: fixes

Add a feature flag for new protocol messages.
Misc fixes.

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

# gpg: Signature made Mon 09 Apr 2018 15:37:29 BST
# gpg:                using RSA key 281F0DB8D28D5469
# gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>"
# gpg:                 aka "Michael S. Tsirkin <mst@redhat.com>"
# Primary key fingerprint: 0270 606B 6F3C DF3D 0B17  0970 C350 3912 AFBE 8E67
#      Subkey fingerprint: 5D09 FD08 71C8 F85B 94CA  8A0D 281F 0DB8 D28D 5469

* remotes/mst/tags/for_upstream:
  virtio-serial: fix heap-over-flow
  vhost: Allow adjoining regions
  contrib/libvhost-user: add the protocol feature used for SET/GET message
  vhost-user: back SET/GET_CONFIG requests with a protocol feature
  vhost-user-blk: set config ops before vhost-user init

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

contrib/libvhost-user/libvhost-user.h

@@ -50,6 +50,7 @@ enum VhostUserProtocolFeature {
     VHOST_USER_PROTOCOL_F_CROSS_ENDIAN = 6,
     VHOST_USER_PROTOCOL_F_CRYPTO_SESSION = 7,
     VHOST_USER_PROTOCOL_F_PAGEFAULT = 8,
+    VHOST_USER_PROTOCOL_F_CONFIG = 9,
 
     VHOST_USER_PROTOCOL_F_MAX
 };

docs/interop/vhost-user.txt

@@ -379,6 +379,7 @@ Protocol features
 #define VHOST_USER_PROTOCOL_F_CROSS_ENDIAN   6
 #define VHOST_USER_PROTOCOL_F_CRYPTO_SESSION 7
 #define VHOST_USER_PROTOCOL_F_PAGEFAULT      8
+#define VHOST_USER_PROTOCOL_F_CONFIG         9
 
 Master message types
 --------------------
@@ -664,7 +665,8 @@ Master message types
       Master payload: virtio device config space
       Slave payload: virtio device config space
 
-      Submitted by the vhost-user master to fetch the contents of the virtio
+      When VHOST_USER_PROTOCOL_F_CONFIG is negotiated, this message is
+      submitted by the vhost-user master to fetch the contents of the virtio
       device configuration space, vhost-user slave's payload size MUST match
       master's request, vhost-user slave uses zero length of payload to
       indicate an error to vhost-user master. The vhost-user master may
@@ -677,7 +679,8 @@ Master message types
       Master payload: virtio device config space
       Slave payload: N/A
 
-      Submitted by the vhost-user master when the Guest changes the virtio
+      When VHOST_USER_PROTOCOL_F_CONFIG is negotiated, this message is
+      submitted by the vhost-user master when the Guest changes the virtio
       device configuration space and also can be used for live migration
       on the destination host. The vhost-user slave must check the flags
       field, and slaves MUST NOT accept SET_CONFIG for read-only
@@ -766,13 +769,13 @@ Slave message types
      Slave payload: N/A
      Master payload: N/A
 
-     Vhost-user slave sends such messages to notify that the virtio device's
+     When VHOST_USER_PROTOCOL_F_CONFIG is negotiated, vhost-user slave sends
-     configuration space has changed, for those host devices which can support
+     such messages to notify that the virtio device's configuration space has
-     such feature, host driver can send VHOST_USER_GET_CONFIG message to slave
+     changed, for those host devices which can support such feature, host
-     to get the latest content. If VHOST_USER_PROTOCOL_F_REPLY_ACK is
+     driver can send VHOST_USER_GET_CONFIG message to slave to get the latest
-     negotiated, and slave set the VHOST_USER_NEED_REPLY flag, master must
+     content. If VHOST_USER_PROTOCOL_F_REPLY_ACK is negotiated, and slave set
-     respond with zero when operation is successfully completed, or non-zero
+     the VHOST_USER_NEED_REPLY flag, master must respond with zero when
-     otherwise.
+     operation is successfully completed, or non-zero otherwise.
 
 VHOST_USER_PROTOCOL_F_REPLY_ACK:
 -------------------------------

hw/block/vhost-user-blk.c

@@ -259,6 +259,8 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
     s->dev.vq_index = 0;
     s->dev.backend_features = 0;
 
+    vhost_dev_set_config_notifier(&s->dev, &blk_ops);
+
     ret = vhost_dev_init(&s->dev, &s->chardev, VHOST_BACKEND_TYPE_USER, 0);
     if (ret < 0) {
         error_setg(errp, "vhost-user-blk: vhost initialization failed: %s",
@@ -277,8 +279,6 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
         s->blkcfg.num_queues = s->num_queues;
     }
 
-    vhost_dev_set_config_notifier(&s->dev, &blk_ops);
-
     return;
 
 vhost_err:

hw/char/virtio-serial-bus.c

@@ -580,13 +580,16 @@ static void set_config(VirtIODevice *vdev, const uint8_t *config_data)
     VirtIOSerial *vser = VIRTIO_SERIAL(vdev);
     struct virtio_console_config *config =
         (struct virtio_console_config *)config_data;
-    uint8_t emerg_wr_lo = le32_to_cpu(config->emerg_wr);
     VirtIOSerialPort *port = find_first_connected_console(vser);
     VirtIOSerialPortClass *vsc;
+    uint8_t emerg_wr_lo;
 
-    if (!config->emerg_wr) {
+    if (!virtio_has_feature(vser->host_features,
+        VIRTIO_CONSOLE_F_EMERG_WRITE) || !config->emerg_wr) {
         return;
     }
+
+    emerg_wr_lo = le32_to_cpu(config->emerg_wr);
     /* Make sure we don't misdetect an emergency write when the guest
      * does a short config write after an emergency write. */
     config->emerg_wr = 0;

hw/virtio/vhost-user.c

@@ -46,6 +46,7 @@ enum VhostUserProtocolFeature {
     VHOST_USER_PROTOCOL_F_CROSS_ENDIAN = 6,
     VHOST_USER_PROTOCOL_F_CRYPTO_SESSION = 7,
     VHOST_USER_PROTOCOL_F_PAGEFAULT = 8,
+    VHOST_USER_PROTOCOL_F_CONFIG = 9,
     VHOST_USER_PROTOCOL_F_MAX
 };
 
@@ -1211,6 +1212,17 @@ static int vhost_user_init(struct vhost_dev *dev, void *opaque)
 
         dev->protocol_features =
             protocol_features & VHOST_USER_PROTOCOL_FEATURE_MASK;
+
+        if (!dev->config_ops || !dev->config_ops->vhost_dev_config_notifier) {
+            /* Don't acknowledge CONFIG feature if device doesn't support it */
+            dev->protocol_features &= ~(1ULL << VHOST_USER_PROTOCOL_F_CONFIG);
+        } else if (!(protocol_features &
+                    (1ULL << VHOST_USER_PROTOCOL_F_CONFIG))) {
+            error_report("Device expects VHOST_USER_PROTOCOL_F_CONFIG "
+                    "but backend does not support it.");
+            return -1;
+        }
+
         err = vhost_user_set_protocol_features(dev, dev->protocol_features);
         if (err < 0) {
             return err;
@@ -1405,6 +1417,11 @@ static int vhost_user_get_config(struct vhost_dev *dev, uint8_t *config,
         .hdr.size = VHOST_USER_CONFIG_HDR_SIZE + config_len,
     };
 
+    if (!virtio_has_feature(dev->protocol_features,
+                VHOST_USER_PROTOCOL_F_CONFIG)) {
+        return -1;
+    }
+
     if (config_len > VHOST_USER_MAX_CONFIG_SIZE) {
         return -1;
     }
@@ -1448,6 +1465,11 @@ static int vhost_user_set_config(struct vhost_dev *dev, const uint8_t *data,
         .hdr.size = VHOST_USER_CONFIG_HDR_SIZE + size,
     };
 
+    if (!virtio_has_feature(dev->protocol_features,
+                VHOST_USER_PROTOCOL_F_CONFIG)) {
+        return -1;
+    }
+
     if (reply_supported) {
         msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
     }

hw/virtio/vhost.c

@@ -595,10 +595,15 @@ static void vhost_region_add_section(struct vhost_dev *dev,
                                         prev_sec->offset_within_address_space,
                                         prev_sec->offset_within_region);
             } else {
-                error_report("%s: Overlapping but not coherent sections "
+                /* adjoining regions are fine, but overlapping ones with
-                             "at %"PRIx64,
+                 * different blocks/offsets shouldn't happen
-                             __func__, mrs_gpa);
+                 */
-                return;
+                if (mrs_gpa != prev_gpa_end + 1) {
+                    error_report("%s: Overlapping but not coherent sections "
+                                 "at %"PRIx64,
+                                 __func__, mrs_gpa);
+                    return;
+                }
             }
         }
     }
@@ -1451,7 +1456,6 @@ int vhost_dev_set_config(struct vhost_dev *hdev, const uint8_t *data,
 void vhost_dev_set_config_notifier(struct vhost_dev *hdev,
                                    const VhostDevConfigOps *ops)
 {
-    assert(hdev->vhost_ops);
     hdev->config_ops = ops;
 }