From 1342ea3b7a14657c3e9f6e38ea3dcc0c2f42939e Mon Sep 17 00:00:00 2001
From: Markus Armbruster <armbru@redhat.com>
Date: Mon, 29 Oct 2018 07:01:37 +0100
Subject: [PATCH 07/22] ivshmem: Fix unplug of device "ivshmem-plain"
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RH-Author: Markus Armbruster <armbru@redhat.com>
Message-id: <20181029070137.21196-4-armbru@redhat.com>
Patchwork-id: 82900
O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH 3/3] ivshmem: Fix unplug of device "ivshmem-plain"
Bugzilla: 1620373
RH-Acked-by: David Hildenbrand <david@redhat.com>
RH-Acked-by: Igor Mammedov <imammedo@redhat.com>
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Acked-by: Marc-André Lureau <marcandre.lureau@redhat.com>

Commit 2aece63c8a "hostmem: detect host backend memory is being used
properly" fixed "ivshmem-plain" to reject memory backends that are
already in use, and to block their deletion while in use.  Two bugs
escaped review:

* New ivshmem_plain_exit() fails to call ivshmem_exit().  This breaks
  unplug.  Reproducer: migration after unplug still fails with
  "Migration is disabled when using feature 'peer mode' in device
  'ivshmem'".

* It failed to update legacy "ivshmem".  Harmless, because it creates
  the memory backend itself, and nothing else should use it.

Fix by moving the two host_memory_backend_set_mapped() calls into
ivshmem_common_realize() and ivshmem_exit(), guarded by s->hostmem.

Fixes: 2aece63c8a9d2c3a8ff41d2febc4cdeff2633331
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180926163709.22876-1-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit b266f1d1123396f9f5df865508f7555ab0c9582a)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/misc/ivshmem.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index 47456b8..28e55d4 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -917,6 +917,7 @@ static void ivshmem_common_realize(PCIDevice *dev, Error **errp)
         IVSHMEM_DPRINTF("using hostmem\n");
 
         s->ivshmem_bar2 = host_memory_backend_get_memory(s->hostmem);
+        host_memory_backend_set_mapped(s->hostmem, true);
     } else {
         Chardev *chr = qemu_chr_fe_get_driver(&s->server_chr);
         assert(chr);
@@ -999,6 +1000,10 @@ static void ivshmem_exit(PCIDevice *dev)
         vmstate_unregister_ram(s->ivshmem_bar2, DEVICE(dev));
     }
 
+    if (s->hostmem) {
+        host_memory_backend_set_mapped(s->hostmem, false);
+    }
+
     if (s->peers) {
         for (i = 0; i < s->nb_peers; i++) {
             close_peer_eventfds(s, i);
@@ -1107,14 +1112,6 @@ static void ivshmem_plain_realize(PCIDevice *dev, Error **errp)
     }
 
     ivshmem_common_realize(dev, errp);
-    host_memory_backend_set_mapped(s->hostmem, true);
-}
-
-static void ivshmem_plain_exit(PCIDevice *pci_dev)
-{
-    IVShmemState *s = IVSHMEM_COMMON(pci_dev);
-
-    host_memory_backend_set_mapped(s->hostmem, false);
 }
 
 static void ivshmem_plain_class_init(ObjectClass *klass, void *data)
@@ -1123,7 +1120,6 @@ static void ivshmem_plain_class_init(ObjectClass *klass, void *data)
     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
 
     k->realize = ivshmem_plain_realize;
-    k->exit = ivshmem_plain_exit;
     dc->props = ivshmem_plain_properties;
     dc->vmsd = &ivshmem_plain_vmsd;
 }
-- 
1.8.3.1