rdma: Fix incorrect description in comments

Since we have supported memory hotplug, VM's ram include pc.ram
and hotplug-memory.

Fix the confused description for rdma migration: pc.ram -> VM's ram

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

docs/rdma.txt

@@ -18,7 +18,7 @@ Contents:
 * RDMA Migration Protocol Description
 * Versioning and Capabilities
 * QEMUFileRDMA Interface
-* Migration of pc.ram
+* Migration of VM's ram
 * Error handling
 * TODO
 
@@ -149,7 +149,7 @@ The only difference between a SEND message and an RDMA
 message is that SEND messages cause notifications
 to be posted to the completion queue (CQ) on the
 infiniband receiver side, whereas RDMA messages (used
-for pc.ram) do not (to behave like an actual DMA).
+for VM's ram) do not (to behave like an actual DMA).
 
 Messages in infiniband require two things:
 
@@ -355,7 +355,7 @@ If the buffer is empty, then we follow the same steps
 listed above and issue another "QEMU File" protocol command,
 asking for a new SEND message to re-fill the buffer.
 
-Migration of pc.ram:
+Migration of VM's ram:
 ====================
 
 At the beginning of the migration, (migration-rdma.c),

migration-rdma.c

@@ -2523,7 +2523,7 @@ static void *qemu_rdma_data_init(const char *host_port, Error **errp)
 /*
  * QEMUFile interface to the control channel.
  * SEND messages for control only.
- * pc.ram is handled with regular RDMA messages.
+ * VM's ram is handled with regular RDMA messages.
  */
 static int qemu_rdma_put_buffer(void *opaque, const uint8_t *buf,
                                 int64_t pos, int size)
@@ -2539,7 +2539,7 @@ static int qemu_rdma_put_buffer(void *opaque, const uint8_t *buf,
 
     /*
      * Push out any writes that
-     * we're queued up for pc.ram.
+     * we're queued up for VM's ram.
      */
     ret = qemu_rdma_write_flush(f, rdma);
     if (ret < 0) {