Index: qemu/vl.c
===================================================================
--- qemu.orig/vl.c	2007-11-10 15:35:51.000000000 +0000
+++ qemu/vl.c	2007-11-10 15:40:59.000000000 +0000
@@ -1537,8 +1537,46 @@
 }
 
 /***********************************************************/
-/* character device */
+/* Helpers for vectored IO*/
+static void qemu_readv_with_read(void *opaque, IOReadHandler *fd_read,
+                                 const struct qemu_iovec *vector, int count)
+{
+#if 1
+    int i, currlen = 0;
+    char buf[8192];
+
+    if (fd_read) {
+        for (i = 0; i < count; i++) {
+            if (currlen + vector[i].iov_len < sizeof(buf))
+                memcpy(&buf[currlen], vector[i].iov_base, vector[i].iov_len);
+            else
+                fprintf(stderr, "bad currlen %d iov.len %ld\n", currlen, vector[i].iov_len);
+            currlen += vector[i].iov_len;
+        }
+        fd_read(opaque, buf, currlen);
+    }
+#else
+    int i;
+
+    if (fd_read)
+        for (i = 0; i < count; i++)
+            fd_read(opaque, vector[i].iov_base, vector[i].iov_len);
+#endif
+}
 
+static void qemu_read_with_readv(void *opaque, IOReadvHandler *fd_readv,
+                                 const uint8_t *buf, int size)
+{
+    struct qemu_iovec iov;
+
+    iov.iov_base = buf;
+    iov.iov_len = size;
+    if (fd_readv)
+        fd_readv(opaque, &iov, 1);
+}
+
+/***********************************************************/
+/* character device */
 static void qemu_chr_event(CharDriverState *s, int event)
 {
     if (!s->chr_event)
@@ -3570,6 +3608,18 @@
     return vc;
 }
 
+VLANClientState *qemu_new_vlan_client_iov(VLANState *vlan,
+                                          IOReadvHandler *fd_readv,
+                                          IOCanRWHandler *fd_can_read,
+                                          void *opaque)
+{
+    VLANClientState *vc;
+
+    vc = qemu_new_vlan_client(vlan, NULL, fd_can_read, opaque);
+    vc->fd_readv = fd_readv;
+    return vc;
+}
+
 int qemu_can_send_packet(VLANClientState *vc1)
 {
     VLANState *vlan = vc1->vlan;
@@ -3595,7 +3645,26 @@
 #endif
     for(vc = vlan->first_client; vc != NULL; vc = vc->next) {
         if (vc != vc1) {
-            vc->fd_read(vc->opaque, buf, size);
+            if (vc->fd_read)
+                vc->fd_read(vc->opaque, buf, size);
+            else if (vc->fd_readv)
+                qemu_read_with_readv(vc->opaque, vc->fd_readv, buf, size);
+        }
+    }
+}
+
+void qemu_send_packet_iov(VLANClientState *vc1, const struct qemu_iovec *vector,
+                          int count)
+{
+    VLANState *vlan = vc1->vlan;
+    VLANClientState *vc;
+
+    for(vc = vlan->first_client; vc != NULL; vc = vc->next) {
+        if (vc != vc1) {
+            if (vc->fd_readv)
+                vc->fd_readv(vc->opaque, vector, count);
+            else if (vc->fd_read)
+                qemu_readv_with_read(vc->opaque, vc->fd_read, vector, count);
         }
     }
 }
@@ -3623,6 +3692,13 @@
     qemu_send_packet(slirp_vc, pkt, pkt_len);
 }
 
+void slirp_output_iov(const struct qemu_iovec *vector, int count)
+{
+    if (!slirp_vc)
+        return;
+    qemu_send_packet_iov(slirp_vc, vector, count);
+}
+
 static void slirp_receive(void *opaque, const uint8_t *buf, int size)
 {
 #if 0
@@ -4941,13 +5017,12 @@
 
 static IOHandlerRecord *first_io_handler;
 
-/* XXX: fd_read_poll should be suppressed, but an API change is
-   necessary in the character devices to suppress fd_can_read(). */
-int qemu_set_fd_handler2(int fd,
-                         IOCanRWHandler *fd_read_poll,
-                         IOHandler *fd_read,
-                         IOHandler *fd_write,
-                         void *opaque)
+static IOHandlerRecord *
+qemu_set_fd_handler3(int fd,
+                     IOCanRWHandler *fd_read_poll,
+                     IOHandler *fd_read,
+                     IOHandler *fd_write,
+                     void *opaque)
 {
     IOHandlerRecord **pioh, *ioh;
 
@@ -4970,17 +5045,38 @@
         }
         ioh = qemu_mallocz(sizeof(IOHandlerRecord));
         if (!ioh)
-            return -1;
+            return NULL;
         ioh->next = first_io_handler;
         first_io_handler = ioh;
     found:
         ioh->fd = fd;
         ioh->fd_read_poll = fd_read_poll;
         ioh->fd_read = fd_read;
+#if 0
+        if (!fd_read)
+            ioh->fd_readv = NULL;
+#endif
         ioh->fd_write = fd_write;
         ioh->opaque = opaque;
         ioh->deleted = 0;
     }
+    return ioh;
+}
+
+/* XXX: fd_read_poll should be suppressed, but an API change is
+   necessary in the character devices to suppress fd_can_read(). */
+int qemu_set_fd_handler2(int fd,
+                         IOCanRWHandler *fd_read_poll,
+                         IOHandler *fd_read,
+                         IOHandler *fd_write,
+                         void *opaque)
+{
+    IOHandlerRecord *ioh;
+
+    ioh = qemu_set_fd_handler3(fd, NULL, fd_read, fd_write, opaque);
+    if (!ioh)
+        return -1;
+
     return 0;
 }
 
@@ -4992,6 +5088,25 @@
     return qemu_set_fd_handler2(fd, NULL, fd_read, fd_write, opaque);
 }
 
+#if 0
+int qemu_set_fd_handler_iov(int fd,
+                            IOHandler *fd_readv,
+                            IOHandler *fd_writev,
+                            void *opaque)
+{
+    IOHandlerRecord *ioh;
+
+    ioh = qemu_set_fd_handler3(fd, NULL, NULL, NULL, opaque);
+    if (!ioh)
+        return -1;
+
+    ioh->fd_readv = fd_readv;
+    ioh->fd_writev = fd_writev;
+
+    return 0;
+}
+#endif
+
 /***********************************************************/
 /* Polling handling */
 
Index: qemu/vl.h
===================================================================
--- qemu.orig/vl.h	2007-11-10 15:40:53.000000000 +0000
+++ qemu/vl.h	2007-11-10 15:40:59.000000000 +0000
@@ -267,6 +267,12 @@
 /* async I/O support */
 
 typedef void IOReadHandler(void *opaque, const uint8_t *buf, int size);
+struct qemu_iovec {
+    void *iov_base;
+    size_t iov_len;
+};
+typedef void IOReadvHandler(void *opaque, const struct qemu_iovec *vector,
+                            int count);
 typedef int IOCanRWHandler(void *opaque);
 typedef void IOHandler(void *opaque);
 
@@ -279,6 +285,10 @@
                         IOHandler *fd_read,
                         IOHandler *fd_write,
                         void *opaque);
+int qemu_set_fd_handler_iov(int fd,
+                            IOHandler *fd_readv,
+                            IOHandler *fd_writev,
+                            void *opaque);
 
 /* Polling handling */
 
@@ -433,6 +443,7 @@
 
 struct VLANClientState {
     IOReadHandler *fd_read;
+    IOReadvHandler *fd_readv;
     /* Packets may still be sent if this returns zero.  It's used to
        rate-limit the slirp code.  */
     IOCanRWHandler *fd_can_read;
@@ -454,8 +465,14 @@
                                       IOReadHandler *fd_read,
                                       IOCanRWHandler *fd_can_read,
                                       void *opaque);
+VLANClientState *qemu_new_vlan_client_iov(VLANState *vlan,
+                                          IOReadvHandler *fd_readv,
+                                          IOCanRWHandler *fd_can_read,
+                                          void *opaque);
 int qemu_can_send_packet(VLANClientState *vc);
 void qemu_send_packet(VLANClientState *vc, const uint8_t *buf, int size);
+void qemu_send_packet_iov(VLANClientState *vc, const struct qemu_iovec *vector,
+                          int count);
 void qemu_handler_true(void *opaque);
 
 void do_info_network(void);
Index: qemu/slirp/libslirp.h
===================================================================
--- qemu.orig/slirp/libslirp.h	2007-10-27 14:58:40.000000000 +0000
+++ qemu/slirp/libslirp.h	2007-11-10 15:40:59.000000000 +0000
@@ -17,6 +17,8 @@
 /* you must provide the following functions: */
 int slirp_can_output(void);
 void slirp_output(const uint8_t *pkt, int pkt_len);
+struct qemu_iovec;
+void slirp_output_iov(const struct qemu_iovec *vector, int count);
 
 int slirp_redir(int is_udp, int host_port,
                 struct in_addr guest_addr, int guest_port);
Index: qemu/slirp/slirp.c
===================================================================
--- qemu.orig/slirp/slirp.c	2007-10-27 14:58:40.000000000 +0000
+++ qemu/slirp/slirp.c	2007-11-10 15:40:59.000000000 +0000
@@ -636,19 +636,22 @@
 /* output the IP packet to the ethernet device */
 void if_encap(const uint8_t *ip_data, int ip_data_len)
 {
-    uint8_t buf[1600];
-    struct ethhdr *eh = (struct ethhdr *)buf;
-
-    if (ip_data_len + ETH_HLEN > sizeof(buf))
-        return;
+    struct ethhdr buf, *eh = &buf;
+    struct {
+        void *data;
+        size_t len;
+    } iov[2];
 
     memcpy(eh->h_dest, client_ethaddr, ETH_ALEN);
     memcpy(eh->h_source, special_ethaddr, ETH_ALEN - 1);
     /* XXX: not correct */
     eh->h_source[5] = CTL_ALIAS;
     eh->h_proto = htons(ETH_P_IP);
-    memcpy(buf + sizeof(struct ethhdr), ip_data, ip_data_len);
-    slirp_output(buf, ip_data_len + ETH_HLEN);
+    iov[0].data = &buf;
+    iov[0].len = sizeof(struct ethhdr);
+    iov[1].data = ip_data;
+    iov[1].len = ip_data_len;
+    slirp_output_iov(iov, 2);
 }
 
 int slirp_redir(int is_udp, int host_port,