qemu

vmnet-common.m (11306B)

---

 /*
  * vmnet-common.m - network client wrapper for Apple vmnet.framework
  *
  * Copyright(c) 2022 Vladislav Yaroshchuk <vladislav.yaroshchuk@jetbrains.com>
  * Copyright(c) 2021 Phillip Tennen <phillip@axleos.com>
  *
  * 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/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>
 
 
 static void vmnet_send_completed(NetClientState *nc, ssize_t len);
 
 
 const char *vmnet_status_map_str(vmnet_return_t status)
 {
     switch (status) {
     case VMNET_SUCCESS:
         return "success";
     case VMNET_FAILURE:
         return "general failure (possibly not enough privileges)";
     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";
 #if defined(MAC_OS_VERSION_11_0) && \
     MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_VERSION_11_0
     case VMNET_SHARING_SERVICE_BUSY:
         return "conflict, sharing service is in use";
 #endif
     default:
         return "unknown vmnet error";
     }
 }
 
 
 /**
  * Write packets from QEMU to vmnet interface.
  *
  * 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 performance having .receive() only.
  */
 ssize_t vmnet_receive_common(NetClientState *nc,
                              const uint8_t *buf,
                              size_t size)
 {
     VmnetState *s = DO_UPCAST(VmnetState, nc, nc);
     struct vmpktdesc packet;
     struct iovec iov;
     int pkt_cnt;
     vmnet_return_t if_status;
 
     if (size > s->max_packet_size) {
         warn_report("vmnet: packet is too big, %zu > %" PRIu64,
             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));
         return -1;
     }
 
     if (pkt_cnt) {
         return size;
     }
     return 0;
 }
 
 
 /**
  * Read packets from vmnet interface and write them
  * to temporary buffers in VmnetState.
  *
  * Returns read packets number (may be 0) on success,
  * -1 on error
  */
 static int vmnet_read_packets(VmnetState *s)
 {
     assert(s->packets_send_current_pos == s->packets_send_end_pos);
 
     struct vmpktdesc *packets = s->packets_buf;
     vmnet_return_t status;
     int i;
 
     /* Read as many packets as present */
     s->packets_send_current_pos = 0;
     s->packets_send_end_pos = VMNET_PACKETS_LIMIT;
     for (i = 0; i < s->packets_send_end_pos; ++i) {
         packets[i].vm_pkt_size = s->max_packet_size;
         packets[i].vm_pkt_iovcnt = 1;
         packets[i].vm_flags = 0;
     }
 
     status = vmnet_read(s->vmnet_if, packets, &s->packets_send_end_pos);
     if (status != VMNET_SUCCESS) {
         error_printf("vmnet: read failed: %s\n",
                      vmnet_status_map_str(status));
         s->packets_send_current_pos = 0;
         s->packets_send_end_pos = 0;
         return -1;
     }
     return s->packets_send_end_pos;
 }
 
 
 /**
  * Write packets from temporary buffers in VmnetState
  * to QEMU.
  */
 static void vmnet_write_packets_to_qemu(VmnetState *s)
 {
     while (s->packets_send_current_pos < s->packets_send_end_pos) {
         ssize_t size = qemu_send_packet_async(&s->nc,
                                       s->iov_buf[s->packets_send_current_pos].iov_base,
                                       s->packets_buf[s->packets_send_current_pos].vm_pkt_size,
                                       vmnet_send_completed);
 
         if (size == 0) {
             /* QEMU is not ready to consume more packets -
              * stop and wait for completion callback call */
             return;
         }
         ++s->packets_send_current_pos;
     }
 }
 
 
 /**
  * Bottom half callback that transfers packets from vmnet interface
  * to QEMU.
  *
  * The process of transferring packets is three-staged:
  * 1. Handle vmnet event;
  * 2. Read packets from vmnet interface into temporary buffer;
  * 3. Write packets from temporary buffer to QEMU.
  *
  * QEMU may suspend this process on the last stage, returning 0 from
  * qemu_send_packet_async function. If this happens, we should
  * respectfully wait until it is ready to consume more packets,
  * write left ones in temporary buffer and only after this
  * continue reading more packets from vmnet interface.
  *
  * Packets to be transferred are stored into packets_buf,
  * in the window [packets_send_current_pos..packets_send_end_pos)
  * including current_pos, excluding end_pos.
  *
  * Thus, if QEMU is not ready, buffer is not read and
  * packets_send_current_pos < packets_send_end_pos.
  */
 static void vmnet_send_bh(void *opaque)
 {
     NetClientState *nc = (NetClientState *) opaque;
     VmnetState *s = DO_UPCAST(VmnetState, nc, nc);
 
     /*
      * Do nothing if QEMU is not ready - wait
      * for completion callback invocation
      */
     if (s->packets_send_current_pos < s->packets_send_end_pos) {
         return;
     }
 
     /* Read packets from vmnet interface */
     if (vmnet_read_packets(s) > 0) {
         /* Send them to QEMU */
         vmnet_write_packets_to_qemu(s);
     }
 }
 
 
 /**
  * Completion callback to be invoked by QEMU when it becomes
  * ready to consume more packets.
  */
 static void vmnet_send_completed(NetClientState *nc, ssize_t len)
 {
     VmnetState *s = DO_UPCAST(VmnetState, nc, nc);
 
     /* Callback is invoked eq queued packet is sent */
     ++s->packets_send_current_pos;
 
     /* Complete sending packets left in VmnetState buffers */
     vmnet_write_packets_to_qemu(s);
 
     /* And read new ones from vmnet if VmnetState buffer is ready */
     if (s->packets_send_current_pos < s->packets_send_end_pos) {
         qemu_bh_schedule(s->send_bh);
     }
 }
 
 
 static void vmnet_bufs_init(VmnetState *s)
 {
     struct vmpktdesc *packets = s->packets_buf;
     struct iovec *iov = s->iov_buf;
     int i;
 
     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;
     }
 }
 
 
 int vmnet_if_create(NetClientState *nc,
                     xpc_object_t if_desc,
                     Error **errp)
 {
     VmnetState *s = DO_UPCAST(VmnetState, nc, nc);
     dispatch_semaphore_t if_created_sem = dispatch_semaphore_create(0);
     __block vmnet_return_t if_status;
 
     s->if_queue = dispatch_queue_create(
         "org.qemu.vmnet.if_queue",
         DISPATCH_QUEUE_SERIAL
     );
 
     xpc_dictionary_set_bool(
         if_desc,
         vmnet_allocate_mac_address_key,
         false
     );
 
 #ifdef DEBUG
     qemu_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);
                              qemu_log("  %s=%s\n", k, desc);
                              free(desc);
                              return true;
                          });
 #endif /* DEBUG */
 
     s->vmnet_if = vmnet_start_interface(
         if_desc,
         s->if_queue,
         ^(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;
             }
 
 #ifdef DEBUG
             qemu_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);
                                      qemu_log("  %s=%s\n", k, desc);
                                      free(desc);
                                      return true;
                                  });
 #endif /* DEBUG */
 
             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);
 
             dispatch_semaphore_signal(if_created_sem);
         });
 
     if (s->vmnet_if == NULL) {
         dispatch_release(s->if_queue);
         dispatch_release(if_created_sem);
         error_setg(errp,
                    "unable to create interface with requested params");
         return -1;
     }
 
     dispatch_semaphore_wait(if_created_sem, DISPATCH_TIME_FOREVER);
     dispatch_release(if_created_sem);
 
     if (if_status != VMNET_SUCCESS) {
         dispatch_release(s->if_queue);
         error_setg(errp,
                    "cannot create vmnet interface: %s",
                    vmnet_status_map_str(if_status));
         return -1;
     }
 
     s->send_bh = aio_bh_new(qemu_get_aio_context(), vmnet_send_bh, nc);
     vmnet_bufs_init(s);
 
     s->packets_send_current_pos = 0;
     s->packets_send_end_pos = 0;
 
     vmnet_interface_set_event_callback(
         s->vmnet_if,
         VMNET_INTERFACE_PACKETS_AVAILABLE,
         s->if_queue,
         ^(interface_event_t event_id, xpc_object_t event) {
             assert(event_id == VMNET_INTERFACE_PACKETS_AVAILABLE);
             /*
              * This function is being called from a non qemu thread, so
              * we only schedule a BH, and do the rest of the io completion
              * handling from vmnet_send_bh() which runs in a qemu context.
              */
             qemu_bh_schedule(s->send_bh);
         });
 
     return 0;
 }
 
 
 void vmnet_cleanup_common(NetClientState *nc)
 {
     VmnetState *s = DO_UPCAST(VmnetState, nc, nc);
     dispatch_semaphore_t if_stopped_sem;
 
     if (s->vmnet_if == NULL) {
         return;
     }
 
     if_stopped_sem = dispatch_semaphore_create(0);
     vmnet_stop_interface(
         s->vmnet_if,
         s->if_queue,
         ^(vmnet_return_t status) {
             assert(status == VMNET_SUCCESS);
             dispatch_semaphore_signal(if_stopped_sem);
         });
     dispatch_semaphore_wait(if_stopped_sem, DISPATCH_TIME_FOREVER);
 
     qemu_purge_queued_packets(nc);
 
     qemu_bh_delete(s->send_bh);
     dispatch_release(if_stopped_sem);
     dispatch_release(s->if_queue);
 
     for (int i = 0; i < VMNET_PACKETS_LIMIT; ++i) {
         g_free(s->iov_buf[i].iov_base);
     }
 }