net/vmnet: implement shared mode (vmnet-shared)

Interaction with vmnet.framework in different modes
differs only on configuration stage, so we can create
common `send`, `receive`, etc. procedures and reuse them.

vmnet.framework supports iov, but writing more than
one iov into vmnet interface fails with
'VMNET_INVALID_ARGUMENT'. Collecting provided iovs into
one and passing it to vmnet works fine. That's the
reason why receive_iov() left unimplemented. But it still
works with good enough performance having .receive()
implemented only.

Also, there is no way to unsubscribe from vmnet packages
receiving except registering and unregistering event
callback or simply drop packages just ignoring and
not processing them when related flag is set. Here we do
using the second way.

Signed-off-by: Phillip Tennen <phillip@axleos.com>
Signed-off-by: Vladislav Yaroshchuk <yaroshchuk2000@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

net/vmnet-common.m

@@ -10,10 +10,321 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/main-loop.h"
+#include "qemu/log.h"
 #include "qapi/qapi-types-net.h"
 #include "vmnet_int.h"
 #include "clients.h"
 #include "qemu/error-report.h"
 #include "qapi/error.h"
 
 #include <vmnet/vmnet.h>
+#include <dispatch/dispatch.h>
+
+#ifdef DEBUG
+#define D(x) x
+#define D_LOG(...) qemu_log(__VA_ARGS__)
+#else
+#define D(x) do { } while (0)
+#define D_LOG(...) do { } while (0)
+#endif
+
+typedef struct vmpktdesc vmpktdesc_t;
+typedef struct iovec iovec_t;
+
+static void vmnet_set_send_enabled(VmnetCommonState *s, bool enable)
+{
+    s->send_enabled = enable;
+}
+
+
+static void vmnet_send_completed(NetClientState *nc, ssize_t len)
+{
+    VmnetCommonState *s = DO_UPCAST(VmnetCommonState, nc, nc);
+    vmnet_set_send_enabled(s, true);
+}
+
+
+static void vmnet_send(NetClientState *nc,
+                       interface_event_t event_id,
+                       xpc_object_t event)
+{
+    assert(event_id == VMNET_INTERFACE_PACKETS_AVAILABLE);
+
+    VmnetCommonState *s;
+    uint64_t packets_available;
+
+    struct iovec *iov;
+    struct vmpktdesc *packets;
+    int pkt_cnt;
+    int i;
+
+    vmnet_return_t if_status;
+    ssize_t size;
+
+    s = DO_UPCAST(VmnetCommonState, nc, nc);
+
+    packets_available = xpc_dictionary_get_uint64(
+        event,
+        vmnet_estimated_packets_available_key
+    );
+
+    pkt_cnt = (packets_available < VMNET_PACKETS_LIMIT) ?
+              packets_available :
+              VMNET_PACKETS_LIMIT;
+
+
+    iov = s->iov_buf;
+    packets = s->packets_buf;
+
+    for (i = 0; i < pkt_cnt; ++i) {
+        packets[i].vm_pkt_size = s->max_packet_size;
+        packets[i].vm_pkt_iovcnt = 1;
+        packets[i].vm_flags = 0;
+    }
+
+    if_status = vmnet_read(s->vmnet_if, packets, &pkt_cnt);
+    if (if_status != VMNET_SUCCESS) {
+        error_printf("vmnet: read failed: %s\n",
+                     vmnet_status_map_str(if_status));
+    }
+    qemu_mutex_lock_iothread();
+    for (i = 0; i < pkt_cnt; ++i) {
+        size = qemu_send_packet_async(nc,
+                                      iov[i].iov_base,
+                                      packets[i].vm_pkt_size,
+                                      vmnet_send_completed);
+        if (size == 0) {
+            vmnet_set_send_enabled(s, false);
+        } else if (size < 0) {
+            break;
+        }
+    }
+    qemu_mutex_unlock_iothread();
+
+}
+
+
+static void vmnet_register_event_callback(VmnetCommonState *s)
+{
+    dispatch_queue_t avail_pkt_q = dispatch_queue_create(
+        "org.qemu.vmnet.if_queue",
+        DISPATCH_QUEUE_SERIAL
+    );
+
+    vmnet_interface_set_event_callback(
+        s->vmnet_if,
+        VMNET_INTERFACE_PACKETS_AVAILABLE,
+        avail_pkt_q,
+        ^(interface_event_t event_id, xpc_object_t event) {
+          if (s->send_enabled) {
+              vmnet_send(&s->nc, event_id, event);
+          }
+        });
+}
+
+
+static void vmnet_bufs_init(VmnetCommonState *s)
+{
+    int i;
+    struct vmpktdesc *packets;
+    struct iovec *iov;
+
+    packets = s->packets_buf;
+    iov = s->iov_buf;
+
+    for (i = 0; i < VMNET_PACKETS_LIMIT; ++i) {
+        iov[i].iov_len = s->max_packet_size;
+        iov[i].iov_base = g_malloc0(iov[i].iov_len);
+        packets[i].vm_pkt_iov = iov + i;
+    }
+}
+
+
+const char *vmnet_status_map_str(vmnet_return_t status)
+{
+    switch (status) {
+    case VMNET_SUCCESS:
+        return "success";
+    case VMNET_FAILURE:
+        return "general failure";
+    case VMNET_MEM_FAILURE:
+        return "memory allocation failure";
+    case VMNET_INVALID_ARGUMENT:
+        return "invalid argument specified";
+    case VMNET_SETUP_INCOMPLETE:
+        return "interface setup is not complete";
+    case VMNET_INVALID_ACCESS:
+        return "invalid access, permission denied";
+    case VMNET_PACKET_TOO_BIG:
+        return "packet size is larger than MTU";
+    case VMNET_BUFFER_EXHAUSTED:
+        return "buffers exhausted in kernel";
+    case VMNET_TOO_MANY_PACKETS:
+        return "packet count exceeds limit";
+    case VMNET_SHARING_SERVICE_BUSY:
+        return "conflict, sharing service is in use";
+    default:
+        return "unknown vmnet error";
+    }
+}
+
+
+int vmnet_if_create(NetClientState *nc,
+                    xpc_object_t if_desc,
+                    Error **errp,
+                    void (*completion_callback)(xpc_object_t interface_param))
+{
+    VmnetCommonState *s;
+
+    dispatch_queue_t if_create_q;
+    dispatch_semaphore_t if_created_sem;
+
+    __block vmnet_return_t if_status;
+
+    if_create_q = dispatch_queue_create("org.qemu.vmnet.create",
+                                        DISPATCH_QUEUE_SERIAL);
+    if_created_sem = dispatch_semaphore_create(0);
+
+    xpc_dictionary_set_bool(
+        if_desc,
+        vmnet_allocate_mac_address_key,
+        false
+    );
+
+    D(D_LOG("vmnet.start.interface_desc:\n");
+    xpc_dictionary_apply(if_desc,
+                         ^bool(const char *k, xpc_object_t v) {
+                           char *desc = xpc_copy_description(v);
+                           D_LOG("  %s=%s\n", k, desc);
+                           free(desc);
+                           return true;
+                         }));
+
+    s = DO_UPCAST(VmnetCommonState, nc, nc);
+    s->vmnet_if = vmnet_start_interface(
+        if_desc,
+        if_create_q,
+        ^(vmnet_return_t status, xpc_object_t interface_param) {
+          if_status = status;
+          if (status != VMNET_SUCCESS || !interface_param) {
+              dispatch_semaphore_signal(if_created_sem);
+              return;
+          }
+
+          D(D_LOG("vmnet.start.interface_param:\n");
+                xpc_dictionary_apply(interface_param,
+                                     ^bool(const char *k, xpc_object_t v) {
+                                       char *desc = xpc_copy_description(v);
+                                       D_LOG("  %s=%s\n", k, desc);
+                                       free(desc);
+                                       return true;
+                                     }));
+
+          s->mtu = xpc_dictionary_get_uint64(
+              interface_param,
+              vmnet_mtu_key);
+          s->max_packet_size = xpc_dictionary_get_uint64(
+              interface_param,
+              vmnet_max_packet_size_key);
+
+          if (completion_callback) {
+              completion_callback(interface_param);
+          }
+          dispatch_semaphore_signal(if_created_sem);
+        });
+
+    if (s->vmnet_if == NULL) {
+        error_setg(errp, "unable to create interface with requested params");
+        return -1;
+    }
+
+    dispatch_semaphore_wait(if_created_sem, DISPATCH_TIME_FOREVER);
+    dispatch_release(if_create_q);
+
+    if (if_status != VMNET_SUCCESS) {
+        error_setg(errp,
+                   "cannot create vmnet interface: %s",
+                   vmnet_status_map_str(if_status));
+        return -1;
+    }
+
+    vmnet_register_event_callback(s);
+    vmnet_bufs_init(s);
+    vmnet_set_send_enabled(s, true);
+
+    return 0;
+}
+
+
+ssize_t vmnet_receive_common(NetClientState *nc,
+                             const uint8_t *buf,
+                             size_t size)
+{
+    VmnetCommonState *s;
+    vmpktdesc_t packet;
+    iovec_t iov;
+    int pkt_cnt;
+    vmnet_return_t if_status;
+
+    s = DO_UPCAST(VmnetCommonState, nc, nc);
+
+    if (size > s->max_packet_size) {
+        warn_report("vmnet: packet is too big, %zu > %llu\n",
+                    packet.vm_pkt_size,
+                    s->max_packet_size);
+        return -1;
+    }
+
+    iov.iov_base = (char *) buf;
+    iov.iov_len = size;
+
+    packet.vm_pkt_iovcnt = 1;
+    packet.vm_flags = 0;
+    packet.vm_pkt_size = size;
+    packet.vm_pkt_iov = &iov;
+
+    pkt_cnt = 1;
+    if_status = vmnet_write(s->vmnet_if, &packet, &pkt_cnt);
+
+    if (if_status != VMNET_SUCCESS) {
+        error_report("vmnet: write error: %s\n",
+                     vmnet_status_map_str(if_status));
+    }
+
+    if (if_status == VMNET_SUCCESS && pkt_cnt) {
+        return size;
+    }
+    return 0;
+}
+
+
+void vmnet_cleanup_common(NetClientState *nc)
+{
+    VmnetCommonState *s;
+    dispatch_queue_t if_destroy_q;
+
+    s = DO_UPCAST(VmnetCommonState, nc, nc);
+
+    qemu_purge_queued_packets(nc);
+    vmnet_set_send_enabled(s, false);
+
+    if (s->vmnet_if == NULL) {
+        return;
+    }
+
+    if_destroy_q = dispatch_queue_create(
+        "org.qemu.vmnet.destroy",
+        DISPATCH_QUEUE_SERIAL
+    );
+
+    vmnet_stop_interface(
+        s->vmnet_if,
+        if_destroy_q,
+        ^(vmnet_return_t status) {
+        });
+
+    for (int i = 0; i < VMNET_PACKETS_LIMIT; ++i) {
+        g_free(s->iov_buf[i].iov_base);
+    }
+}