[PATCH v8 10/20] multi-process: setup memory manager for remote device

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

SyncSysMemMsg message format is defined. It is used to send
file descriptors of the RAM regions to remote device.
RAM on the remote device is configured with a set of file descriptors.
Old RAM regions are deleted and new regions, each with an fd, is
added to the RAM.

Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
---
 MAINTAINERS                     |  2 ++
 hw/i386/Makefile.objs           |  1 +
 hw/i386/remote-memory.c         | 58 +++++++++++++++++++++++++++++++++++++++++
 include/hw/i386/remote-memory.h | 19 ++++++++++++++
 include/io/mpqemu-link.h        | 13 +++++++++
 io/mpqemu-link.c                | 13 +++++++++
 6 files changed, 106 insertions(+)
 create mode 100644 hw/i386/remote-memory.c
 create mode 100644 include/hw/i386/remote-memory.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 9fd278f..2da7680 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3049,6 +3049,8 @@ F: include/io/mpqemu-link.h
 F: hw/i386/remote-msg.c
 F: include/hw/i386/remote-obj.h
 F: hw/i386/remote-obj.c
+F: include/hw/i386/remote-memory.h
+F: hw/i386/remote-memory.c
 
 Build and test automation
 -------------------------
diff --git a/hw/i386/Makefile.objs b/hw/i386/Makefile.objs
index 30d7102..4ba47e0 100644
--- a/hw/i386/Makefile.objs
+++ b/hw/i386/Makefile.objs
@@ -17,6 +17,7 @@ obj-$(CONFIG_PC) += port92.o
 obj-$(CONFIG_MPQEMU) += remote.o
 obj-$(CONFIG_MPQEMU) += remote-msg.o
 obj-$(CONFIG_MPQEMU) += remote-obj.o
+obj-$(CONFIG_MPQEMU) += remote-memory.o
 
 obj-y += kvmvapic.o
 obj-$(CONFIG_ACPI) += acpi-common.o
diff --git a/hw/i386/remote-memory.c b/hw/i386/remote-memory.c
new file mode 100644
index 0000000..759b8e9
--- /dev/null
+++ b/hw/i386/remote-memory.c
@@ -0,0 +1,58 @@
+/*
+ * Memory manager for remote device
+ *
+ * Copyright © 2018, 2020 Oracle and/or its affiliates.
+ *
+ * This work is licensed under the terms of the GNU GPL, 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-memory.h"
+#include "exec/address-spaces.h"
+#include "exec/ram_addr.h"
+#include "qapi/error.h"
+
+void remote_sysmem_reconfig(MPQemuMsg *msg, Error **errp)
+{
+    SyncSysmemMsg *sysmem_info = &msg->data1.sync_sysmem;
+    MemoryRegion *sysmem, *subregion, *next;
+    static unsigned int suffix;
+    Error *local_err = NULL;
+    char *name;
+    int region;
+
+    sysmem = get_system_memory();
+
+    memory_region_transaction_begin();
+
+    QTAILQ_FOREACH_SAFE(subregion, &sysmem->subregions, subregions_link, next) {
+        if (subregion->ram) {
+            memory_region_del_subregion(sysmem, subregion);
+            object_unparent(OBJECT(subregion));
+        }
+    }
+
+    for (region = 0; region < msg->num_fds; region++) {
+        subregion = g_new(MemoryRegion, 1);
+        name = g_strdup_printf("remote-mem-%u", suffix++);
+        memory_region_init_ram_from_fd(subregion, NULL,
+                                       name, sysmem_info->sizes[region],
+                                       RAM_SHARED, msg->fds[region],
+                                       sysmem_info->offsets[region],
+                                       &local_err);
+        g_free(name);
+        if (local_err) {
+            error_propagate(errp, local_err);
+            break;
+        }
+
+        memory_region_add_subregion(sysmem, sysmem_info->gpas[region],
+                                    subregion);
+    }
+
+    memory_region_transaction_commit();
+}
diff --git a/include/hw/i386/remote-memory.h b/include/hw/i386/remote-memory.h
new file mode 100644
index 0000000..aab3e4d
--- /dev/null
+++ b/include/hw/i386/remote-memory.h
@@ -0,0 +1,19 @@
+/*
+ * Memory manager for remote device
+ *
+ * Copyright © 2018, 2020 Oracle and/or its affiliates.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#ifndef REMOTE_MEMORY_H
+#define REMOTE_MEMORY_H
+
+#include "exec/hwaddr.h"
+#include "io/mpqemu-link.h"
+
+void remote_sysmem_reconfig(MPQemuMsg *msg, Error **errp);
+
+#endif
diff --git a/include/io/mpqemu-link.h b/include/io/mpqemu-link.h
index 8591ad2..98383f9 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 "io/channel-socket.h"
+#include "exec/cpu-common.h"
+#include "exec/hwaddr.h"
 
 #define REMOTE_MAX_FDS 8
 
@@ -25,13 +27,22 @@
  *
  * MPQemuCmd enum type to specify the command to be executed on the remote
  * device.
+ *
+ * SYNC_SYSMEM      Shares QEMU's RAM with remote device's RAM
  */
 typedef enum {
     INIT = 0,
+    SYNC_SYSMEM,
     RET_MSG,
     MAX = INT_MAX,
 } MPQemuCmd;
 
+typedef struct {
+    hwaddr gpas[REMOTE_MAX_FDS];
+    uint64_t sizes[REMOTE_MAX_FDS];
+    off_t offsets[REMOTE_MAX_FDS];
+} SyncSysmemMsg;
+
 /**
  * Maximum size of data2 field in the message to be transmitted.
  */
@@ -50,6 +61,7 @@ typedef enum {
  * MPQemuMsg Format of the message sent to the remote device from QEMU.
  *
  */
+
 typedef struct {
     int cmd;
     int bytestream;
@@ -57,6 +69,7 @@ typedef struct {
 
     union {
         uint64_t u64;
+        SyncSysmemMsg sync_sysmem;
     } data1;
 
     int fds[REMOTE_MAX_FDS];
diff --git a/io/mpqemu-link.c b/io/mpqemu-link.c
index d4dd0fe..aad1d77 100644
--- a/io/mpqemu-link.c
+++ b/io/mpqemu-link.c
@@ -245,6 +245,19 @@ bool mpqemu_msg_valid(MPQemuMsg *msg)
             }
         }
     }
+     /* Verify message specific fields. */
+    switch (msg->cmd) {
+    case SYNC_SYSMEM:
+        if (msg->num_fds == 0 || msg->bytestream) {
+            return false;
+        }
+        if (msg->size != sizeof(msg->data1)) {
+            return false;
+        }
+        break;
+    default:
+        break;
+    }
 
     return true;
 }
-- 
1.8.3.1