On Mon, 2026-06-22 at 12:00 +0300, Kostiantyn Kostiuk wrote: > Hi Polina, > > First of all, thanks for your patches. > > Before reviewing this patch, I want to ask: why is it needed? > > I understand the patch "qemu-sockets: Enable AF_VSOCK on Windows", > but AF_VSOCK has the same behavior on Linux and Windows. > I expected that we could totally reuse the POSIX part, so just move it to > common with > some defines like: > ``` > #ifdef G_OS_WIN32 > in_ch = g_io_channel_win32_new_fd(in_fd); > #else > in_ch = g_io_channel_unix_new(in_fd); > #endif > ``` > > We tested our driver with SSH over VSOCK, and standard Linux SSH works > well. > So, what is the difference in this case that you add win32-specific code > for VSOCK?
1. There's no shared GIOChannel path on Windows to #ifdef into. channel-posix.c is built on GIOChannels + g_io_add_watch(); channel-win32.c is built on overlapped I/O over a Win32 HANDLE with a reader thread and a custom GSource. There's no in_ch = g_io_channel_*() line to wrap. vsock is the first GIOChannel-based channel on Windows. 2. g_io_channel_win32_new_fd() is the wrong constructor, as it's for CRT fds, not sockets. GLib wants g_io_channel_win32_new_socket() (it sets up WSAEventSelect). And qemu_accept()/socket_listen() return a CRT fd wrapping a SOCKET via _open_osfhandle(), so we recover it with _get_osfhandle(), which is also why teardown needs the explicit qemu_close_socket_osfhandle() ordering, to avoid a double closesocket(). 3. Winsock disconnect detection differs: GLib passes FD_READ|FD_CLOSE as one G_IO_IN and Winsock reports FD_CLOSE only once, so a peer that writes-then-closes never yields G_IO_HUP and the listener hangs half-open. That's why the MSG_PEEK probe logic is required on Windows, while on POSIX poll()/epoll() reports POLLHUP reliably and doesn't need it. Best regards, Polina. > > Best Regards, > Kostiantyn Kostiuk. > > > On Fri, Jun 19, 2026 at 9:03 PM Polina Vishneva < > [email protected]> wrote: > > > Add vsock-listen channel mode to the Windows guest agent. > > > > The listen/accept path uses the standard QEMU socket helpers > > (socket_parse(), socket_listen(), qemu_accept()) and plugs the resulting > > SOCKET into the GMainLoop via g_io_channel_win32_new_socket(). > > > > Signed-off-by: Polina Vishneva <[email protected]> > > --- > > docs/interop/qemu-ga.rst | 4 + > > qga/channel-win32.c | 257 ++++++++++++++++++++++++++++++++------- > > qga/main.c | 6 + > > 3 files changed, 222 insertions(+), 45 deletions(-) > >
