Add GoldfishPipeServiceOps APIs to wait for guest data.

We need to separate the waiting part out from guest_recv/guest_send
because those calls in qemu are protected by the global qemu mutex.
But when we wait, we need to release the mutex.

Bug: 294378605
Test: CtsGraphicsTestCases
Change-Id: Ic47960d9bd714e5c5a593afd851daa59ce05a7ab

4 files changed, 40 insertions, 0 deletions

diff --git a/host-common/AndroidPipe.cpp b/host-common/AndroidPipe.cpp
index a61fc6e..8a8b592 100644
--- a/host-common/AndroidPipe.cpp
+++ b/host-common/AndroidPipe.cpp
@@ -74,6 +74,10 @@ static BaseStream* asBaseStream(CStream* stream) {
 }
 
 #define CHECK_VM_STATE_LOCK() (void)0
+// b/294378605: Need to implement VM_STATE_LOCK and VM_STATE_UNLOCK for qemu. We leave this empty
+// for now since qemu provides its own implementation of AndroidPipe.cpp.
+#define VM_STATE_LOCK() (void)0
+#define VM_STATE_UNLOCK() (void)0
 
 namespace android {
 
@@ -773,6 +777,14 @@ int android_pipe_guest_recv(void* internalPipe,
     return pipe->onGuestRecv(buffers, numBuffers);
 }
 
+void android_pipe_wait_guest_recv(void* internalPipe) {
+    CHECK_VM_STATE_LOCK();
+    auto pipe = static_cast<AndroidPipe*>(internalPipe);
+    VM_STATE_UNLOCK();
+    pipe->waitGuestRecv();
+    VM_STATE_LOCK();
+}
+
 int android_pipe_guest_send(void** internalPipe,
                             const AndroidPipeBuffer* buffers,
                             int numBuffers) {
@@ -783,6 +795,14 @@ int android_pipe_guest_send(void** internalPipe,
     return pipe->onGuestSend(buffers, numBuffers, internalPipe);
 }
 
+void android_pipe_wait_guest_send(void* internalPipe) {
+    CHECK_VM_STATE_LOCK();
+    auto pipe = static_cast<AndroidPipe*>(internalPipe);
+    VM_STATE_UNLOCK();
+    pipe->waitGuestSend();
+    VM_STATE_LOCK();
+}
+
 void android_pipe_guest_wake_on(void* internalPipe, unsigned wakes) {
     CHECK_VM_STATE_LOCK();
     auto pipe = static_cast<AndroidPipe*>(internalPipe);
diff --git a/host-common/include/host-common/AndroidPipe.h b/host-common/include/host-common/AndroidPipe.h
index 628c34e..ab39dd9 100644
--- a/host-common/include/host-common/AndroidPipe.h
+++ b/host-common/include/host-common/AndroidPipe.h
@@ -166,6 +166,10 @@ public:
     // is no data yet to read.
     virtual int onGuestRecv(AndroidPipeBuffer* buffers, int numBuffers) = 0;
 
+    // A blocking call that waits until guest is able to receive data from the pipe.
+    // This can be used if a previous call to |onGuestRecv| returns PIPE_ERROR_AGAIN.
+    virtual void waitGuestRecv() const {};
+
     // Called from the device thread when the guest wants to send data to
     // the pipe. |buffers| points to an array of |numBuffers| descriptors that
     // specify where to copy the data from. Return the number of bytes that
@@ -176,6 +180,10 @@ public:
                             int numBuffers,
                             void** newPipePtr) = 0;
 
+    // A blocking call that waits until guest is able to send data to the pipe.
+    // This can be used if a previous call to |onGuestSend| returns PIPE_ERROR_AGAIN.
+    virtual void waitGuestSend() const {}
+
     // Called from the device thread when the guest wants to indicate it
     // wants to be woken up when the set of PIPE_WAKE_XXX event bits in |flags|
     // will occur. The pipe implementation should call the wake() method to
diff --git a/host-common/include/host-common/android_pipe_device.h b/host-common/include/host-common/android_pipe_device.h
index 06802f7..3b12247 100644
--- a/host-common/include/host-common/android_pipe_device.h
+++ b/host-common/include/host-common/android_pipe_device.h
@@ -166,10 +166,16 @@ ANDROID_PIPE_DEVICE_EXPORT unsigned android_pipe_guest_poll(void* internal_pipe)
 ANDROID_PIPE_DEVICE_EXPORT int android_pipe_guest_recv(
     void* internal_pipe, AndroidPipeBuffer* buffers, int numBuffers);
 
+// Blocking call that waits until guest is able to receive data.
+ANDROID_PIPE_DEVICE_EXPORT void android_pipe_wait_guest_recv(void* internal_pipe);
+
 // Call the sendBuffers() callback of the client associated with |pipe|.
 ANDROID_PIPE_DEVICE_EXPORT int android_pipe_guest_send(
     void** internal_pipe, const AndroidPipeBuffer* buffer, int numBuffer);
 
+// Blocking call that waits until guest is able to send data.
+ANDROID_PIPE_DEVICE_EXPORT void android_pipe_wait_guest_send(void* internal_pipe);
+
 // Call the wakeOn() callback of the client associated with |pipe|.
 ANDROID_PIPE_DEVICE_EXPORT void android_pipe_guest_wake_on(
     void* internal_pipe, unsigned wakes);
diff --git a/host-common/include/host-common/goldfish_pipe.h b/host-common/include/host-common/goldfish_pipe.h
index f387dcf..b78f493 100644
--- a/host-common/include/host-common/goldfish_pipe.h
+++ b/host-common/include/host-common/goldfish_pipe.h
@@ -123,6 +123,9 @@ typedef struct GoldfishPipeServiceOps {
                       GoldfishPipeBuffer *buffers,
                       int num_buffers);
 
+    // Blocking call that waits until guest is able to receive data through |host_pipe|.
+    void (*wait_guest_recv)(GoldfishHostPipe* host_pipe);
+
     // Called when the guest tries to send data to the host through
     // |host_pipe|. This will try to copy data from the memory ranges
     // decribed by the array |buffers| or |num_buffers| items.
@@ -132,6 +135,9 @@ typedef struct GoldfishPipeServiceOps {
                       const GoldfishPipeBuffer *buffers,
                       int num_buffers);
 
+    // Blocking call that waits until guest is able to send data through |host_pipe|.
+    void (*wait_guest_send)(GoldfishHostPipe* host_pipe);
+
     // Called when the guest wants to be waked on specific events.
     // identified by the |wake_flags| bitmask. The host should call
     // goldfish_pipe_signal_wake() with the appropriate bitmask when