Add vhost-user snapshot support to wmediumd am: 89da3783ed

Original change: https://android-review.googlesource.com/c/platform/external/wmediumd/+/2759933

Change-Id: I72669d0783ca5e4df4d7f3d17d1cc375904bc611
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

2 files changed, 78 insertions, 0 deletions

diff --git a/wmediumd/inc/usfstl/vhostproto.h b/wmediumd/inc/usfstl/vhostproto.h
index 4550179..579af54 100644
--- a/wmediumd/inc/usfstl/vhostproto.h
+++ b/wmediumd/inc/usfstl/vhostproto.h
@@ -8,6 +8,10 @@
 
 #define MAX_REGIONS 8
 
+// For simplicity, we only support snapshotting a fixed number of queues. Should
+// be equal to HWSIM_NUM_VQS.
+#define NUM_SNAPSHOT_QUEUES 2
+
 /* these are from the vhost-user spec */
 
 struct vhost_user_msg_hdr {
@@ -29,11 +33,16 @@ struct vhost_user_region {
 	uint64_t mmap_offset;
 };
 
+struct vhost_user_snapshot {
+	int8_t sleeping[NUM_SNAPSHOT_QUEUES];
+};
+
 struct vhost_user_msg {
 	struct vhost_user_msg_hdr hdr;
 	union {
 #define VHOST_USER_U64_VRING_IDX_MSK	0x7f
 #define VHOST_USER_U64_NO_FD		0x80
+		int8_t i8;
 		uint64_t u64;
 		struct {
 			uint32_t idx, num;
@@ -63,6 +72,13 @@ struct vhost_user_msg {
 			uint64_t size;
 			uint64_t offset;
 		} vring_area;
+		struct {
+			int8_t bool_store;
+			struct vhost_user_snapshot snapshot;
+		}  __attribute__((packed)) snapshot_response;
+		struct {
+			struct vhost_user_snapshot snapshot;
+		} __attribute__((packed)) restore_request;
 	} __attribute__((packed)) payload;
 };
 
@@ -82,6 +98,10 @@ struct vhost_user_msg {
 #define VHOST_USER_GET_CONFIG			24
 #define VHOST_USER_VRING_KICK			35
 #define VHOST_USER_GET_SHARED_MEMORY_REGIONS	41
+#define VHOST_USER_SLEEP			42
+#define VHOST_USER_WAKE				43
+#define VHOST_USER_SNAPSHOT			44
+#define VHOST_USER_RESTORE			45
 
 #define VHOST_USER_SLAVE_CONFIG_CHANGE_MSG	 2
 #define VHOST_USER_SLAVE_VRING_CALL		 4
diff --git a/wmediumd/lib/vhost.c b/wmediumd/lib/vhost.c
index b6a7a70..7e177ac 100644
--- a/wmediumd/lib/vhost.c
+++ b/wmediumd/lib/vhost.c
@@ -41,6 +41,7 @@ struct usfstl_vhost_user_dev_int {
 	struct {
 		struct usfstl_loop_entry entry;
 		bool enabled;
+		bool sleeping;
 		bool triggered;
 		struct vring virtq;
 		int call_fd;
@@ -673,6 +674,63 @@ static void usfstl_vhost_user_handle_msg(struct usfstl_loop_entry *entry)
 		reply_len = sizeof(uint64_t);
 		msg.payload.u64 = 0;
 		break;
+	case VHOST_USER_SLEEP:
+		USFSTL_ASSERT_EQ(len, (ssize_t)0, "%zd");
+		USFSTL_ASSERT_EQ(dev->ext.server->max_queues, NUM_SNAPSHOT_QUEUES, "%d");
+		for (virtq = 0; virtq < dev->ext.server->max_queues; virtq++) {
+			if (dev->virtqs[virtq].enabled) {
+				dev->virtqs[virtq].enabled = false;
+				dev->virtqs[virtq].sleeping = true;
+				usfstl_loop_unregister(&dev->virtqs[virtq].entry);
+			}
+		}
+		break;
+	case VHOST_USER_WAKE:
+		USFSTL_ASSERT_EQ(len, (ssize_t)0, "%zd");
+		USFSTL_ASSERT_EQ(dev->ext.server->max_queues, NUM_SNAPSHOT_QUEUES, "%d");
+		// enable previously enabled queues on wake
+		for (virtq = 0; virtq < dev->ext.server->max_queues; virtq++) {
+			if (dev->virtqs[virtq].sleeping) {
+				dev->virtqs[virtq].enabled = true;
+				dev->virtqs[virtq].sleeping = false;
+				usfstl_loop_register(&dev->virtqs[virtq].entry);
+				// TODO: is this needed?
+				usfstl_vhost_user_virtq_kick(dev, virtq);
+			}
+		}
+		break;
+	case VHOST_USER_SNAPSHOT: {
+		USFSTL_ASSERT_EQ(len, (ssize_t)0, "%zd");
+		USFSTL_ASSERT_EQ(dev->ext.server->max_queues, NUM_SNAPSHOT_QUEUES, "%d");
+		for (virtq = 0; virtq < dev->ext.server->max_queues; virtq++) {
+			msg.payload.snapshot_response.snapshot.sleeping[virtq] = dev->virtqs[virtq].sleeping;
+		}
+		msg.payload.snapshot_response.bool_store = 1;
+		reply_len = (int)sizeof(msg.payload.snapshot_response);
+		break;
+	}
+	case VHOST_USER_RESTORE: {
+		int *fds;
+		USFSTL_ASSERT(len == (int)sizeof(msg.payload.restore_request));
+		USFSTL_ASSERT_EQ(dev->ext.server->max_queues, NUM_SNAPSHOT_QUEUES, "%d");
+
+		fds = (int*)malloc(dev->ext.server->max_queues * sizeof(int));
+		for (virtq = 0; virtq < dev->ext.server->max_queues; virtq++) {
+			fds[virtq] = -1;
+		}
+		usfstl_vhost_user_get_msg_fds(&msghdr, fds, 2);
+
+		for (virtq = 0; virtq < dev->ext.server->max_queues; virtq++) {
+			dev->virtqs[virtq].sleeping = msg.payload.restore_request.snapshot.sleeping[virtq];
+			dev->virtqs[virtq].entry.fd = fds[virtq];
+		}
+
+		free(fds);
+
+		msg.payload.i8 = 1; // success
+		reply_len = sizeof(msg.payload.i8);
+		break;
+	}
 	default:
 		USFSTL_ASSERT(0, "Unsupported message: %d\n", msg.hdr.request);
 	}