[v9,08/20] multi-process: Initialize message handler in remote device

Commit Message

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

From: Jagannathan Raman <[e-mail]>

Initializes the message handler function in the remote process. It is
called whenever there's an event pending on QIOChannel that registers
this function.

Signed-off-by: Elena Ufimtseva <[e-mail]>
Signed-off-by: John G Johnson <[e-mail]>
Signed-off-by: Jagannathan Raman <[e-mail]>
---
 MAINTAINERS              |  1 +
 hw/i386/meson.build      |  1 +
 hw/i386/remote-msg.c     | 66 ++++++++++++++++++++++++++++++++++++++++
 include/hw/i386/remote.h |  4 +++
 4 files changed, 72 insertions(+)
 create mode 100644 hw/i386/remote-msg.c

Comments

Stefan Hajnoczi Sept. 23, 2020, 2:10 p.m. UTC | #1

This is the function that can be converted from a callback to a
coroutine like this:

  void coroutine_fn mpqemu_loop(...)
  {
      for (;;) {
          if (mpqemu_msg_read(...) < 0) {
              /* Fatal connection error (disconnected, etc) */
	      break;
          }

          if (!mpqemu_msg_valid(&msg)) {
              /* Protocol violation, terminate connection */
	      break;
          }

          switch (msg.cmd) {
              /* Dispatch command */
          }
      }
  }

Elena Ufimtseva Sept. 24, 2020, 5:20 p.m. UTC | #2

On Wed, Sep 23, 2020 at 03:10:39PM +0100, Stefan Hajnoczi wrote:
> This is the function that can be converted from a callback to a
> coroutine like this:
> 
>   void coroutine_fn mpqemu_loop(...)
>   {
>       for (;;) {
>           if (mpqemu_msg_read(...) < 0) {
>               /* Fatal connection error (disconnected, etc) */
> 	      break;
>           }
> 
>           if (!mpqemu_msg_valid(&msg)) {
>               /* Protocol violation, terminate connection */
> 	      break;
>           }
> 
>           switch (msg.cmd) {
>               /* Dispatch command */
>           }
>       }
>   }

Ok, thank you! I have something similar.

Elena

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 1ca1f8ccff..9885c9499f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3047,6 +3047,7 @@  F: hw/i386/remote.c
 F: include/hw/i386/remote.h
 F: io/mpqemu-link.c
 F: include/io/mpqemu-link.h
+F: hw/i386/remote-msg.c
 
 Build and test automation
 -------------------------
diff --git a/hw/i386/meson.build b/hw/i386/meson.build
index 1c1668c5db..238ae0879d 100644
--- a/hw/i386/meson.build
+++ b/hw/i386/meson.build
@@ -24,6 +24,7 @@  i386_ss.add(when: 'CONFIG_PC', if_true: files(
   'acpi-build.c',
   'port92.c'))
 i386_ss.add(when: 'CONFIG_MPQEMU', if_true: files('remote.c'))
+i386_ss.add(when: 'CONFIG_MPQEMU', if_true: files('remote-msg.c'))
 
 subdir('kvm')
 subdir('xen')
diff --git a/hw/i386/remote-msg.c b/hw/i386/remote-msg.c
new file mode 100644
index 0000000000..2a855d5850
--- /dev/null
+++ b/hw/i386/remote-msg.c
@@ -0,0 +1,66 @@ 
+/*
+ * Copyright © 2020 Oracle and/or its affiliates.
+ *
+ * This work is licensed under the terms of the GNU GPL-v2, version 2 or later.
+ *
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+
+#include "hw/i386/remote.h"
+#include "io/channel.h"
+#include "io/mpqemu-link.h"
+#include "qapi/error.h"
+#include "sysemu/runstate.h"
+
+gboolean mpqemu_process_msg(QIOChannel *ioc, GIOCondition cond,
+                            gpointer opaque)
+{
+    PCIDevice *pci_dev = (PCIDevice *)opaque;
+    Error *local_err = NULL;
+    MPQemuMsg msg = { 0 };
+    MPQemuRequest req = { 0 };
+
+    if (cond & G_IO_HUP) {
+        qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
+        return FALSE;
+    }
+
+    if (cond & (G_IO_ERR | G_IO_NVAL)) {
+        error_report("Error %d while processing message from proxy"
+                     "in remote process pid=%d", errno, getpid());
+        return FALSE;
+    }
+
+    req.msg = &msg;
+    req.ioc = ioc;
+
+    mpqemu_msg_recv_in_co(&req, ioc, &local_err);
+    if (local_err) {
+        goto exit;
+    }
+
+    if (!mpqemu_msg_valid(&msg)) {
+        error_report("Received invalid message from proxy"
+                     "in remote process pid=%d", getpid());
+        return FALSE;
+    }
+
+    switch (msg.cmd) {
+    default:
+        error_setg(&local_err,
+                   "Unknown command (%d) received for device %s (pid=%d)",
+                   req.msg->cmd, DEVICE(pci_dev)->id, getpid());
+    }
+
+exit:
+    if (local_err) {
+        error_report_err(local_err);
+        return FALSE;
+    }
+
+    return TRUE;
+}
diff --git a/include/hw/i386/remote.h b/include/hw/i386/remote.h
index 5b36b25ca1..7f9028fcce 100644
--- a/include/hw/i386/remote.h
+++ b/include/hw/i386/remote.h
@@ -14,6 +14,7 @@ 
 #include "qom/object.h"
 #include "hw/boards.h"
 #include "hw/pci-host/remote.h"
+#include "io/channel.h"
 
 typedef struct RemoteMachineState {
     MachineState parent_obj;
@@ -25,4 +26,7 @@  typedef struct RemoteMachineState {
 #define REMOTE_MACHINE(obj) \
     OBJECT_CHECK(RemoteMachineState, (obj), TYPE_REMOTE_MACHINE)
 
+gboolean mpqemu_process_msg(QIOChannel *ioc, GIOCondition cond,
+                            gpointer opaque);
+
 #endif