qemu-kvm/0016-virtio-scsi-Reject-scsi-cd-if-data-plane-enabled-RHE.patch
Miroslav Rezanina f788c1346a * Thu Sep 02 2021 Miroslav Rezanina <mrezanin@redhat.com> - 6.1.0-1
- Rebase to QEMU 6.1.0 [bz#1997408]
- Resolves: #bz#1997408
  (Rebase to QEMU 6.1.0)
2021-09-02 02:44:51 -04:00

67 lines
2.7 KiB
Diff

From 121a8bb81575086f84563f1dffc4d045cdc65a64 Mon Sep 17 00:00:00 2001
From: Fam Zheng <famz@redhat.com>
Date: Wed, 14 Jun 2017 15:37:01 +0200
Subject: virtio-scsi: Reject scsi-cd if data plane enabled [RHEL only]
RH-Author: Fam Zheng <famz@redhat.com>
Message-id: <20170614153701.14757-1-famz@redhat.com>
Patchwork-id: 75613
O-Subject: [RHV-7.4 qemu-kvm-rhev PATCH v3] virtio-scsi: Reject scsi-cd if data plane enabled [RHEL only]
Bugzilla: 1378816
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>
We need a fix for RHEL 7.4 and 7.3.z, but unfortunately upstream isn't
ready. If it were, the changes will be too invasive. To have an idea:
https://lists.gnu.org/archive/html/qemu-devel/2017-05/msg05400.html
is an incomplete attempt to fix part of the issue, and the remaining
work unfortunately involve even more complex changes.
As a band-aid, this partially reverts the effect of ef8875b
(virtio-scsi: Remove op blocker for dataplane, since v2.7). We cannot
simply revert that commit as a whole because we already shipped it in
qemu-kvm-rhev 7.3, since when, block jobs has been possible. We should
only block what has been broken. Also, faithfully reverting the above
commit means adding back the removed op blocker, but that is not enough,
because it still crashes when inserting media into an initially empty
scsi-cd.
All in all, scsi-cd on virtio-scsi-dataplane has basically been unusable
unless the scsi-cd never enters an empty state, so, disable it
altogether. Otherwise it would be much more difficult to avoid
crashing.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
hw/scsi/virtio-scsi.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index 6d80730287..bba3d75707 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -896,6 +896,15 @@ static void virtio_scsi_hotplug(HotplugHandler *hotplug_dev, DeviceState *dev,
AioContext *old_context;
int ret;
+ /* XXX: Remove this check once block backend is capable of handling
+ * AioContext change upon eject/insert.
+ * s->ctx is NULL if ioeventfd is off, s->ctx is qemu_get_aio_context() if
+ * data plane is not used, both cases are safe for scsi-cd. */
+ if (s->ctx && s->ctx != qemu_get_aio_context() &&
+ object_dynamic_cast(OBJECT(dev), "scsi-cd")) {
+ error_setg(errp, "scsi-cd is not supported by data plane");
+ return;
+ }
if (s->ctx && !s->dataplane_fenced) {
if (blk_op_is_blocked(sd->conf.blk, BLOCK_OP_TYPE_DATAPLANE, errp)) {
return;
--
2.27.0