From 4c58843e5d3192c67394b28a3330144ea56eefac Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Tue, 18 Jun 2024 12:00:35 +0200 Subject: [PATCH] vhost-user-server: do not set memory fd non-blocking MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In vhost-user-server we set all fd received from the other peer in non-blocking mode. For some of them (e.g. memfd, shm_open, etc.) it's not really needed, because we don't use these fd with blocking operations, but only to map memory. In addition, in some systems this operation can fail (e.g. in macOS setting an fd returned by shm_open() non-blocking fails with errno = ENOTTY). So, let's avoid setting fd non-blocking for those messages that we know carry memory fd (e.g. VHOST_USER_ADD_MEM_REG, VHOST_USER_SET_MEM_TABLE). Reviewed-by: Daniel P. Berrangé Acked-by: Stefan Hajnoczi Reviewed-by: David Hildenbrand Signed-off-by: Stefano Garzarella Message-Id: <20240618100043.144657-6-sgarzare@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- util/vhost-user-server.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c index 3bfb1ad3ec..b19229074a 100644 --- a/util/vhost-user-server.c +++ b/util/vhost-user-server.c @@ -65,6 +65,18 @@ static void vmsg_close_fds(VhostUserMsg *vmsg) static void vmsg_unblock_fds(VhostUserMsg *vmsg) { int i; + + /* + * These messages carry fd used to map memory, not to send/receive messages, + * so this operation is useless. In addition, in some systems this + * operation can fail (e.g. in macOS setting an fd returned by shm_open() + * non-blocking fails with errno = ENOTTY) + */ + if (vmsg->request == VHOST_USER_ADD_MEM_REG || + vmsg->request == VHOST_USER_SET_MEM_TABLE) { + return; + } + for (i = 0; i < vmsg->fd_num; i++) { qemu_socket_set_nonblock(vmsg->fds[i]); }