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vhost-vsock: set vhostfd to non-blocking mode

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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>
Message-Id: <20201029144849.70958-1-sgarzare@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Stefano Garzarella 2020-10-29 15:48:49 +01:00 committed by Michael S. Tsirkin
parent 9aa47edd4e
commit 384c2561bd
1 changed files with 10 additions and 0 deletions
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10
hw/virtio/vhost-vsock.c
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@ -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");