[v4] pci,pc,virtio: features, tests, fixes, cleanups

[PULL v4 43/83] vhost-user: Fix out of order vring host notification handling

Michael S. Tsirkin posted 83 patches 3 years, 1 month ago

Diff against v1 v2 v3
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Maintainers: "Gonglei (Arei)" <arei.gonglei@huawei.com>, "Daniel P. Berrangé" <berrange@redhat.com>, Ani Sinha <ani@anisinha.ca>, "Michael S. Tsirkin" <mst@redhat.com>, Igor Mammedov <imammedo@redhat.com>, Peter Maydell <peter.maydell@linaro.org>, Shannon Zhao <shannon.zhaosl@gmail.com>, Raphael Norwitz <raphael.norwitz@nutanix.com>, Kevin Wolf <kwolf@redhat.com>, Hanna Reitz <hreitz@redhat.com>, Eduardo Habkost <eduardo@habkost.net>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Yanan Wang <wangyanan55@huawei.com>, Ben Widawsky <ben.widawsky@intel.com>, Jonathan Cameron <jonathan.cameron@huawei.com>, Gerd Hoffmann <kraxel@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Richard Henderson <richard.henderson@linaro.org>, Peter Xu <peterx@redhat.com>, Jason Wang <jasowang@redhat.com>, Sergio Lopez <slp@redhat.com>, Dmitry Fleytman <dmitry.fleytman@gmail.com>, Jiri Pirko <jiri@resnulli.us>, Keith Busch <kbusch@kernel.org>, Klaus Jensen <its@irrelevant.dk>, Huai-Cheng Kuo <hchkuo@avery-design.com.tw>, Chris Browy <cbrowy@avery-design.com>, Yuval Shaia <yuval.shaia.ml@gmail.com>, Elena Ufimtseva <elena.ufimtseva@oracle.com>, Jagannathan Raman <jag.raman@oracle.com>, John G Johnson <john.g.johnson@oracle.com>, Alex Williamson <alex.williamson@redhat.com>, "Dr. David Alan Gilbert" <dgilbert@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, "Alex Bennée" <alex.bennee@linaro.org>, Viresh Kumar <viresh.kumar@linaro.org>, Mathieu Poirier <mathieu.poirier@linaro.org>, Eric Auger <eric.auger@redhat.com>, David Hildenbrand <david@redhat.com>, Eric Blake <eblake@redhat.com>, Markus Armbruster <armbru@redhat.com>, Cleber Rosa <crosa@redhat.com>, Wainer dos Santos Moschetta <wainersm@redhat.com>, Beraldo Leal <bleal@redhat.com>

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[PULL v4 43/83] vhost-user: Fix out of order vring host notification handling

Posted by Michael S. Tsirkin 3 years, 1 month ago

From: Yajun Wu <yajunw@nvidia.com>

vhost backend sends host notification for every VQ. If backend creates
VQs in parallel, the VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG may
arrive to QEMU in different order than incremental queue index order.

For example VQ 1's message arrive earlier than VQ 0's:
After alloc VhostUserHostNotifier for VQ 1. GPtrArray becomes

    [ nil, VQ1 pointer ]

After alloc VhostUserHostNotifier for VQ 0. GPtrArray becomes

    [ VQ0 pointer, nil, VQ1 pointer ]

This is wrong. fetch_notifier will return NULL for VQ 1 in
vhost_user_get_vring_base, causes host notifier miss removal(leak).

The fix is to remove current element from GPtrArray, make the right
position for element to insert.

Fixes: 503e355465 ("virtio/vhost-user: dynamically assign VhostUserHostNotifiers")
Signed-off-by: Yajun Wu <yajunw@nvidia.com>
Acked-by: Parav Pandit <parav@nvidia.com>

Message-Id: <20221018023651.1359420-1-yajunw@nvidia.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/virtio/vhost-user.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 03415b6c95..d256ce589b 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -1543,6 +1543,11 @@ static VhostUserHostNotifier *fetch_or_create_notifier(VhostUserState *u,
 
     n = g_ptr_array_index(u->notifiers, idx);
     if (!n) {
+        /*
+         * In case notification arrive out-of-order,
+         * make room for current index.
+         */
+        g_ptr_array_remove_index(u->notifiers, idx);
         n = g_new0(VhostUserHostNotifier, 1);
         n->idx = idx;
         g_ptr_array_insert(u->notifiers, idx, n);
-- 
MST