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 <sgarzare@redhat.com>
---
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");
--
2.26.2