From 384c2561bddfa00cd3eaf9edbc1af6c7c120511f Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Thu, 29 Oct 2020 15:48:49 +0100 Subject: [PATCH] vhost-vsock: set vhostfd to non-blocking mode vhost IOTLB API uses read()/write() to exchange iotlb messages with the kernel module. The QEMU implementation expects a non-blocking fd, indeed commit c471ad0e9b ("vhost_net: device IOTLB support") set it for vhost-net. Without this patch, if we enable iommu for the vhost-vsock device, QEMU can hang when exchanging IOTLB messages. As commit 894022e616 ("net: check if the file descriptor is valid before using it") did for tap, let's use qemu_try_set_nonblock() when fd is provided by the user. Signed-off-by: Stefano Garzarella Message-Id: <20201029144849.70958-1-sgarzare@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/vhost-vsock.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/hw/virtio/vhost-vsock.c b/hw/virtio/vhost-vsock.c index f9db4beb47..8ddfb9abfe 100644 --- a/hw/virtio/vhost-vsock.c +++ b/hw/virtio/vhost-vsock.c @@ -16,6 +16,7 @@ #include "qapi/error.h" #include "hw/virtio/virtio-access.h" #include "qemu/error-report.h" +#include "qemu/sockets.h" #include "hw/qdev-properties.h" #include "hw/virtio/vhost-vsock.h" #include "monitor/monitor.h" @@ -148,6 +149,13 @@ static void vhost_vsock_device_realize(DeviceState *dev, Error **errp) error_prepend(errp, "vhost-vsock: unable to parse vhostfd: "); return; } + + ret = qemu_try_set_nonblock(vhostfd); + if (ret < 0) { + error_setg_errno(errp, -ret, + "vhost-vsock: unable to set non-blocking mode"); + return; + } } else { vhostfd = open("/dev/vhost-vsock", O_RDWR); if (vhostfd < 0) { @@ -155,6 +163,8 @@ static void vhost_vsock_device_realize(DeviceState *dev, Error **errp) "vhost-vsock: failed to open vhost device"); return; } + + qemu_set_nonblock(vhostfd); } vhost_vsock_common_realize(vdev, "vhost-vsock");