[client] implemented the new ivshmem interrupt sync system

client/KVMGFXHeader.h

@@ -23,6 +23,8 @@ struct KVMGFXHeader
 {
   char      magic[sizeof(KVMGFX_HEADER_MAGIC)];
   uint32_t  version;     // version of this structure
+  uint16_t  hostID;      // the host ivshmem client id
+  uint16_t  guestID;     // the guest ivshmem client id
   FrameType frameType;   // the frame type
   FrameComp compType;    // frame compression mode
   uint32_t  width;       // the width

client/ivshmem/ivshmem.c

@@ -9,6 +9,7 @@
 #include <unistd.h>
 #include <stdbool.h>
 #include <stdint.h>
+#include <errno.h>
 
 #include <sys/stat.h>
 #include <sys/socket.h>
@@ -270,6 +271,7 @@ bool ivshmem_read_msg(int64_t * index, int * fd)
   if (!fd)
     return true;
 
+  *fd = -1;
   struct cmsghdr *cmsg;
   for(cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg))
   {
@@ -280,12 +282,14 @@ bool ivshmem_read_msg(int64_t * index, int * fd)
       continue;
     }
 
-    memcpy(fd, CMSG_DATA(cmsg), sizeof(*fd));
+    *fd = *(int*)CMSG_DATA(cmsg);
   }
 
   return true;
 }
 
+// ============================================================================
+
 uint16_t ivshmem_get_id()
 {
   if (!ivshmem.connected)
@@ -455,4 +459,72 @@ bool ivshmem_process()
 
   client->irqs[client->irqCount++] = fd;
   return true;
+}
+
+// ============================================================================
+
+enum IVSHMEMWaitResult ivshmem_wait_irq(uint16_t vector)
+{
+  if (vector > ivshmem.server.irqCount - 1)
+    return false;
+
+  int fd = ivshmem.server.irqs[vector];
+  fd_set fds;
+  FD_ZERO(&fds);
+  FD_SET(fd, &fds);
+
+  struct timeval timeout;
+  timeout.tv_sec  = 1;
+  timeout.tv_usec = 0;
+
+  while(true)
+  {
+    int ret = select(fd+1, &fds, NULL, NULL, &timeout);
+    if (ret < 0)
+    {
+      if (errno == EINTR)
+        continue;
+
+      DEBUG_ERROR("select error");
+      break;
+    }
+
+    if (ret == 0)
+      return IVSHMEM_WAIT_RESULT_TIMEOUT;
+
+    if (FD_ISSET(fd, &fds))
+    {
+      uint64_t kick;
+      read(fd, &kick, sizeof(kick));
+      return IVSHMEM_WAIT_RESULT_OK;
+    }
+  }
+
+  return IVSHMEM_WAIT_RESULT_ERROR;
+}
+
+// ============================================================================
+
+bool ivshmem_kick_irq(uint16_t clientID, uint16_t vector)
+{
+  struct IVSHMEMClient * client = ivshmem_get_client(clientID);
+  if (!client)
+  {
+    DEBUG_ERROR("invalid client");
+    return false;
+  }
+
+  if (vector > client->irqCount - 1)
+  {
+    DEBUG_ERROR("invalid vector for client");
+    return false;
+  }
+
+  int fd = client->irqs[vector];
+  uint64_t kick = ivshmem.server.clientID;
+  if (write(fd, &kick, sizeof(kick)) == sizeof(kick))
+    return true;
+
+  DEBUG_ERROR("failed to send kick");  
+  return false;
 }

client/ivshmem/ivshmem.h

@@ -8,4 +8,14 @@ bool ivshmem_process();
 
 uint16_t ivshmem_get_id();
 void *   ivshmem_get_map();
-size_t   ivshmem_get_map_size();
+size_t   ivshmem_get_map_size();
+
+enum IVSHMEMWaitResult
+{
+  IVSHMEM_WAIT_RESULT_OK,
+  IVSHMEM_WAIT_RESULT_TIMEOUT,
+  IVSHMEM_WAIT_RESULT_ERROR
+};
+
+enum IVSHMEMWaitResult ivshmem_wait_irq(uint16_t vector);
+bool ivshmem_kick_irq(uint16_t clientID, uint16_t vector);

client/main.c

@@ -211,7 +211,6 @@ void drawFunc_YUV420P(CompFunc compFunc, SDL_Texture * texture, uint8_t * dst, c
 
 int renderThread(void * unused)
 {
-  bool                startup    = true;
   struct KVMGFXHeader format;
   SDL_Texture        *texture    = NULL;
   uint8_t             *pixels    = (uint8_t*)(state.shm + 1);
@@ -254,16 +253,40 @@ int renderThread(void * unused)
     if (memcmp(state.shm->magic, KVMGFX_HEADER_MAGIC, sizeof(KVMGFX_HEADER_MAGIC)) != 0)
       continue;
 
-    // if the frame count hasn't changed, we don't do anything
-    if (!startup && format.frames == state.shm->frames)
-    {
-      if (!state.running)
-        break;
-
-      usleep(100);
+    if (state.shm->version != 2)
       continue;
+
+    bool ready = false;
+    bool error = false;
+    while(state.running && !ready && !error)
+    {    
+      // kick the guest and wait for a frame
+      ivshmem_kick_irq(state.shm->guestID, 0);
+      switch(ivshmem_wait_irq(0))
+      {
+        case IVSHMEM_WAIT_RESULT_OK:
+          ready = true;
+          break;
+
+        case IVSHMEM_WAIT_RESULT_TIMEOUT:
+          ready = false;
+          break;
+
+        case IVSHMEM_WAIT_RESULT_ERROR:
+          error = true;
+          break;
+      }  
     }
-    startup = false;
+
+    if (error)
+    {
+      DEBUG_ERROR("error during wait for host");
+      break;
+    }    
+
+//      continue;
+//    }
+//    startup = false;
 
     // if the format is invalid or it has changed
     if (format.frameType == FRAME_TYPE_INVALID || !areFormatsSame(format, *state.shm))
@@ -507,6 +530,7 @@ int main(int argc, char * argv[])
       DEBUG_ERROR("Failed to map memory");
       break;
     }
+    state.shm->hostID = ivshmem_get_id();
 
     if (!spice_connect("127.0.0.1", 5900, ""))
     {