[v9,12/20] multi-process: add proxy communication functions

Commit Message

Elena Ufimtseva Aug. 27, 2020, 6:12 p.m. UTC

From: Elena Ufimtseva <[e-mail]>

Signed-off-by: Elena Ufimtseva <[e-mail]>
Signed-off-by: Jagannathan Raman <[e-mail]>
Signed-off-by: John G Johnson <[e-mail]>
---
 include/io/mpqemu-link.h |  4 ++++
 io/mpqemu-link.c         | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

Comments

Stefan Hajnoczi Sept. 23, 2020, 3:55 p.m. UTC | #1

On Thu, Aug 27, 2020 at 11:12:23AM -0700, [e-mail] wrote:
> +uint64_t mpqemu_msg_send_and_await_reply(MPQemuMsg *msg, PCIProxyDev *pdev,
> +                                         Error **errp)

A doc comment that says "called from a vcpu thread in non-coroutine
context" would help document the constraints.

Reviewed-by: Stefan Hajnoczi <[e-mail]>

Patch

diff --git a/include/io/mpqemu-link.h b/include/io/mpqemu-link.h
index b348c658d1..62425b8f3b 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
 
@@ -77,6 +79,8 @@  typedef struct MPQemuRequest MPQemuRequest;
 void mpqemu_msg_send_in_co(MPQemuRequest *req, QIOChannel *ioc, Error **errp);
 void mpqemu_msg_recv_in_co(MPQemuRequest *req, QIOChannel *ioc, Error **errp);
 
+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 0d1eaaca7f..f5f22267d1 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"
 
 void mpqemu_msg_send(MPQemuMsg *msg, QIOChannel *ioc, Error **errp)
 {
@@ -150,6 +151,43 @@  fail:
     }
 }
 
+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_unlock_iothread();
+    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);
+    qemu_mutex_lock_iothread();
+
+    return ret;
+}
+
 static void coroutine_fn mpqemu_msg_send_co(void *data)
 {
     MPQemuRequest *req = (MPQemuRequest *)data;