From d5a21de3aa2a13ab8bfb4d9d815ae60e04e08f94 Mon Sep 17 00:00:00 2001
From: Avihai Horon <avihaih@nvidia.com>
Date: Thu, 25 Jan 2024 18:25:12 +0200
Subject: [48/99] migration: Fix logic of channels and transport compatibility
 check

commit 3205bebd4fc6dd501fb8b10c93ddce9da18e09db upstream.

The commit in the fixes line mistakenly modified the channels and
transport compatibility check logic so it now checks multi-channel
support only for socket transport type.

Thus, running multifd migration using a transport other than socket that
is incompatible with multi-channels (such as "exec") would lead to a
segmentation fault instead of an error message.
For example:
  (qemu) migrate_set_capability multifd on
  (qemu) migrate -d "exec:cat > /tmp/vm_state"
  Segmentation fault (core dumped)

Fix it by checking multi-channel compatibility for all transport types.

Cc: qemu-stable <qemu-stable@nongnu.org>
Fixes: d95533e1cdcc ("migration: modify migration_channels_and_uri_compatible() for new QAPI syntax")
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240125162528.7552-2-avihaih@nvidia.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Jason Zeng <jason.zeng@intel.com>
---
 migration/migration.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index f428839dd6..0e8255180d 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -127,11 +127,17 @@ static bool migration_needs_multiple_sockets(void)
     return migrate_multifd() || migrate_postcopy_preempt();
 }
 
-static bool transport_supports_multi_channels(SocketAddress *saddr)
+static bool transport_supports_multi_channels(MigrationAddress *addr)
 {
-    return saddr->type == SOCKET_ADDRESS_TYPE_INET ||
-           saddr->type == SOCKET_ADDRESS_TYPE_UNIX ||
-           saddr->type == SOCKET_ADDRESS_TYPE_VSOCK;
+    if (addr->transport == MIGRATION_ADDRESS_TYPE_SOCKET) {
+        SocketAddress *saddr = &addr->u.socket;
+
+        return saddr->type == SOCKET_ADDRESS_TYPE_INET ||
+               saddr->type == SOCKET_ADDRESS_TYPE_UNIX ||
+               saddr->type == SOCKET_ADDRESS_TYPE_VSOCK;
+    }
+
+    return false;
 }
 
 static bool
@@ -139,8 +145,7 @@ migration_channels_and_transport_compatible(MigrationAddress *addr,
                                             Error **errp)
 {
     if (migration_needs_multiple_sockets() &&
-        (addr->transport == MIGRATION_ADDRESS_TYPE_SOCKET) &&
-        !transport_supports_multi_channels(&addr->u.socket)) {
+        !transport_supports_multi_channels(addr)) {
         error_setg(errp, "Migration requires multi-channel URIs (e.g. tcp)");
         return false;
     }
-- 
2.33.0