Re: [PATCH v18 3/7] net/vmnet: implement shared mode (vmnet-shared)

[Vladislav Yaroshchuk]

On Tue, Mar 15, 2022 at 11:07 PM Akihiko Odaki 
wrote:

> On 2022/03/16 4:59, Vladislav Yaroshchuk wrote:
> > Interaction with vmnet.framework in different modes
> > differs only on configuration stage, so we can create
> > common `send`, `receive`, etc. procedures and reuse them.
> >
> > Signed-off-by: Phillip Tennen 
> > Signed-off-by: Vladislav Yaroshchuk 
> > ---
> >   net/vmnet-common.m | 368 +
> >   net/vmnet-shared.c |  90 ++-
> >   net/vmnet_int.h|  40 -
> >   3 files changed, 493 insertions(+), 5 deletions(-)
> >
> > diff --git a/net/vmnet-common.m b/net/vmnet-common.m
> > index 06326efb1c..b9dac7b241 100644
> > --- a/net/vmnet-common.m
> > +++ b/net/vmnet-common.m
> > @@ -10,6 +10,8 @@
> >*/
> >
> >   #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"
> > @@ -17,4 +19,370 @@
> >   #include "qapi/error.h"
> >
> >   #include 
> > +#include 
> >
> > +
>

[...]


> > +/**
> > + * 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]
> > + * excluding current_pos, including end_pos.
>
> I wonder why you changed the window from [packets_send_current_pos,
> packets_send_end_pos). It is an unconventional way to represent such
> kind of window, requires signed integers and calculating
> packets_send_current_pos + 1 before operating with the first item of the
> window.
>
>
Did this mistakenly while removing send_enabled :facepalm:
Sorry for this.

Submitting v19 with this fixed.

Best Regards,
Vladislav Yaroshchuk



> Regards,
> Akihiko Odaki
>
> + *
> > + * 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 

Re: [PATCH v18 3/7] net/vmnet: implement shared mode (vmnet-shared)

[Akihiko Odaki]

On 2022/03/16 4:59, Vladislav Yaroshchuk wrote:

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

Signed-off-by: Phillip Tennen 
Signed-off-by: Vladislav Yaroshchuk 
---
  net/vmnet-common.m | 368 +
  net/vmnet-shared.c |  90 ++-
  net/vmnet_int.h|  40 -
  3 files changed, 493 insertions(+), 5 deletions(-)

diff --git a/net/vmnet-common.m b/net/vmnet-common.m
index 06326efb1c..b9dac7b241 100644
--- a/net/vmnet-common.m
+++ b/net/vmnet-common.m
@@ -10,6 +10,8 @@
   */
  
  #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"
@@ -17,4 +19,370 @@
  #include "qapi/error.h"
  
  #include 

+#include 
  
+

+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 = 
+pkt_cnt = 1;
+
+if_status = vmnet_write(s->vmnet_if, , _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 pkt_cnt;
+int i;
+
+/* Read as many packets as present */
+pkt_cnt = VMNET_PACKETS_LIMIT;
+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;
+}
+
+status = vmnet_read(s->vmnet_if, packets, _cnt);
+if (status != VMNET_SUCCESS) {
+error_printf("vmnet: read failed: %s\n",
+ vmnet_status_map_str(status));
+s->packets_send_current_pos = -1;
+s->packets_send_end_pos = -1;
+return -1;
+}
+
+/*
+ * Adjust pointers: packets to be sent
+ * lay in (packets_send_current_pos..packets_send_end_pos]
+ * - excluding current_pos, including end_pos.
+ */
+s->packets_send_current_pos = -1;
+s->packets_send_end_pos = pkt_cnt - 1;
+
+return pkt_cnt;
+}
+
+
+/**
+ * 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) {
+int next_packet_pos = s->packets_send_current_pos + 1;
+ssize_t size = qemu_send_packet_async(>nc,
+