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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Wed, 27 Apr 2022 15:35:36 +0100
Subject: [PATCH] virtio-scsi: fix ctrl and event handler functions in
dataplane mode
Commit f34e8d8b8d48d73f36a67b6d5e492ef9784b5012 ("virtio-scsi: prepare
virtio_scsi_handle_cmd for dataplane") prepared the virtio-scsi cmd
virtqueue handler function to be used in both the dataplane and
non-datpalane code paths.
It failed to convert the ctrl and event virtqueue handler functions,
which are not designed to be called from the dataplane code path but
will be since the ioeventfd is set up for those virtqueues when
dataplane starts.
Convert the ctrl and event virtqueue handler functions now so they
operate correctly when called from the dataplane code path. Avoid code
duplication by extracting this code into a helper function.
Fixes: f34e8d8b8d48d73f36a67b6d5e492ef9784b5012 ("virtio-scsi: prepare virtio_scsi_handle_cmd for dataplane")
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20220427143541.119567-2-stefanha@redhat.com
[Fixed s/by used/be used/ typo pointed out by Michael Tokarev
<mjt@tls.msk.ru>.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
hw/scsi/virtio-scsi.c | 42 +++++++++++++++++++++++++++---------------
1 file changed, 27 insertions(+), 15 deletions(-)
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index 34a968ecfb5b45d5b2f09aef052197aceab4728e..417fbc71d66340c38f285d3d77912b675eb4947e 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -472,16 +472,32 @@ bool virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq)
return progress;
}
+/*
+ * If dataplane is configured but not yet started, do so now and return true on
+ * success.
+ *
+ * Dataplane is started by the core virtio code but virtqueue handler functions
+ * can also be invoked when a guest kicks before DRIVER_OK, so this helper
+ * function helps us deal with manually starting ioeventfd in that case.
+ */
+static bool virtio_scsi_defer_to_dataplane(VirtIOSCSI *s)
+{
+ if (!s->ctx || s->dataplane_started) {
+ return false;
+ }
+
+ virtio_device_start_ioeventfd(&s->parent_obj.parent_obj);
+ return !s->dataplane_fenced;
+}
+
static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIOSCSI *s = (VirtIOSCSI *)vdev;
- if (s->ctx) {
- virtio_device_start_ioeventfd(vdev);
- if (!s->dataplane_fenced) {
- return;
- }
+ if (virtio_scsi_defer_to_dataplane(s)) {
+ return;
}
+
virtio_scsi_acquire(s);
virtio_scsi_handle_ctrl_vq(s, vq);
virtio_scsi_release(s);
@@ -720,12 +736,10 @@ static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)
/* use non-QOM casts in the data path */
VirtIOSCSI *s = (VirtIOSCSI *)vdev;
- if (s->ctx && !s->dataplane_started) {
- virtio_device_start_ioeventfd(vdev);
- if (!s->dataplane_fenced) {
- return;
- }
+ if (virtio_scsi_defer_to_dataplane(s)) {
+ return;
}
+
virtio_scsi_acquire(s);
virtio_scsi_handle_cmd_vq(s, vq);
virtio_scsi_release(s);
@@ -855,12 +869,10 @@ static void virtio_scsi_handle_event(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIOSCSI *s = VIRTIO_SCSI(vdev);
- if (s->ctx) {
- virtio_device_start_ioeventfd(vdev);
- if (!s->dataplane_fenced) {
- return;
- }
+ if (virtio_scsi_defer_to_dataplane(s)) {
+ return;
}
+
virtio_scsi_acquire(s);
virtio_scsi_handle_event_vq(s, vq);
virtio_scsi_release(s);
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