From 0c9753ebda274b0e618d7b4032bb2d83d27483ed Mon Sep 17 00:00:00 2001 From: Laurent Vivier Date: Mon, 27 Jul 2020 17:33:19 +0200 Subject: virtio-pci: fix virtio_pci_queue_enabled() In legacy mode, virtio_pci_queue_enabled() falls back to virtio_queue_enabled() to know if the queue is enabled. But virtio_queue_enabled() calls again virtio_pci_queue_enabled() if k->queue_enabled is set. This ends in a crash after a stack overflow. The problem can be reproduced with "-device virtio-net-pci,disable-legacy=off,disable-modern=true -net tap,vhost=on" And a look to the backtrace is very explicit: ... #4 0x000000010029a438 in virtio_queue_enabled () #5 0x0000000100497a9c in virtio_pci_queue_enabled () ... #130902 0x000000010029a460 in virtio_queue_enabled () #130903 0x0000000100497a9c in virtio_pci_queue_enabled () #130904 0x000000010029a460 in virtio_queue_enabled () #130905 0x0000000100454a20 in vhost_net_start () ... This patch fixes the problem by introducing a new function for the legacy case and calls it from virtio_pci_queue_enabled(). It also calls it from virtio_queue_enabled() to avoid code duplication. Fixes: f19bcdfedd53 ("virtio-pci: implement queue_enabled method") Cc: Jason Wang Cc: Cindy Lu CC: Michael S. Tsirkin Signed-off-by: Laurent Vivier Message-Id: <20200727153319.43716-1-lvivier@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/virtio-pci.c | 2 +- hw/virtio/virtio.c | 7 ++++++- 2 files changed, 7 insertions(+), 2 deletions(-) (limited to 'hw/virtio') diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c index ada1101..4ad3ad8 100644 --- a/hw/virtio/virtio-pci.c +++ b/hw/virtio/virtio-pci.c @@ -1116,7 +1116,7 @@ static bool virtio_pci_queue_enabled(DeviceState *d, int n) return proxy->vqs[vdev->queue_sel].enabled; } - return virtio_queue_enabled(vdev, n); + return virtio_queue_enabled_legacy(vdev, n); } static int virtio_pci_add_mem_cap(VirtIOPCIProxy *proxy, diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 546a198..e983025 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -3309,6 +3309,11 @@ hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n) return vdev->vq[n].vring.desc; } +bool virtio_queue_enabled_legacy(VirtIODevice *vdev, int n) +{ + return virtio_queue_get_desc_addr(vdev, n) != 0; +} + bool virtio_queue_enabled(VirtIODevice *vdev, int n) { BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); @@ -3317,7 +3322,7 @@ bool virtio_queue_enabled(VirtIODevice *vdev, int n) if (k->queue_enabled) { return k->queue_enabled(qbus->parent, n); } - return virtio_queue_get_desc_addr(vdev, n) != 0; + return virtio_queue_enabled_legacy(vdev, n); } hwaddr virtio_queue_get_avail_addr(VirtIODevice *vdev, int n) -- cgit v1.1