[PATCH v11 11/19] multi-process: add proxy communication functions

[Jagannathan Raman <jag.raman@oracle.com>]

From: Elena Ufimtseva <elena.ufimtseva@oracle.com>

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/io/mpqemu-link.h |  4 ++++
 io/mpqemu-link.c         | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/include/io/mpqemu-link.h b/include/io/mpqemu-link.h
index e33181a..4bea5da 100644
--- a/include/io/mpqemu-link.h
+++ b/include/io/mpqemu-link.h
@@ -15,6 +15,8 @@
 #include "qemu/thread.h"
 #include "io/channel.h"
 #include "exec/hwaddr.h"
+#include "io/channel-socket.h"
+#include "hw/pci/proxy.h"
 
 #define REMOTE_MAX_FDS 8
 
@@ -65,6 +67,8 @@ typedef struct {
     int num_fds;
 } QEMU_PACKED MPQemuMsg;
 
+uint64_t mpqemu_msg_send_and_await_reply(MPQemuMsg *msg, PCIProxyDev *pdev,
+                                         Error **errp);
 void mpqemu_msg_send(MPQemuMsg *msg, QIOChannel *ioc, Error **errp);
 void mpqemu_msg_recv(MPQemuMsg *msg, QIOChannel *ioc, Error **errp);
 
diff --git a/io/mpqemu-link.c b/io/mpqemu-link.c
index b30e27c..1339cc7 100644
--- a/io/mpqemu-link.c
+++ b/io/mpqemu-link.c
@@ -17,6 +17,7 @@
 #include "qemu/iov.h"
 #include "qemu/error-report.h"
 #include "qemu/main-loop.h"
+#include "io/channel.h"
 
 /*
  * Send message over the ioc QIOChannel.
@@ -214,6 +215,43 @@ fail:
     }
 }
 
+/*
+ * Called from VCPU thread in non-coroutine context.
+ */
+uint64_t mpqemu_msg_send_and_await_reply(MPQemuMsg *msg, PCIProxyDev *pdev,
+                                         Error **errp)
+{
+    MPQemuMsg msg_reply = {0};
+    uint64_t ret = UINT64_MAX;
+    Error *local_err = NULL;
+
+    qemu_mutex_lock(&pdev->io_mutex);
+    mpqemu_msg_send(msg, pdev->ioc, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        goto exit_send;
+    }
+
+    mpqemu_msg_recv(&msg_reply, pdev->ioc, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        goto exit_send;
+    }
+
+    if (!mpqemu_msg_valid(&msg_reply) || msg_reply.cmd != RET_MSG) {
+        error_setg(errp, "ERROR: Invalid reply received for command %d",
+                         msg->cmd);
+        goto exit_send;
+    } else {
+        ret = msg_reply.data.u64;
+    }
+
+ exit_send:
+    qemu_mutex_unlock(&pdev->io_mutex);
+
+    return ret;
+}
+
 bool mpqemu_msg_valid(MPQemuMsg *msg)
 {
     if (msg->cmd >= MPQEMU_CMD_MAX && msg->cmd < 0) {
-- 
1.8.3.1