diff --git a/fsdev/file-op-9p.h b/fsdev/file-op-9p.h
index f2f7772c86..d51cec2f3b 100644
--- a/fsdev/file-op-9p.h
+++ b/fsdev/file-op-9p.h
@@ -64,6 +64,10 @@ typedef struct ExtendedOps {
  */
 #define V9FS_REMAP_INODES           0x00000200
 #define V9FS_FORBID_MULTIDEVS       0x00000400
+/*
+ * Disables certain performance warnings from being logged on host side.
+ */
+#define V9FS_NO_PERF_WARN           0x00000800
 
 #define V9FS_SEC_MASK               0x0000003C
 
diff --git a/hw/9pfs/9p-synth.c b/hw/9pfs/9p-synth.c
index 7eb210ffa8..cec8c0eefc 100644
--- a/hw/9pfs/9p-synth.c
+++ b/hw/9pfs/9p-synth.c
@@ -541,6 +541,8 @@ static int synth_init(FsContext *ctx, Error **errp)
     QLIST_INIT(&synth_root.child);
     qemu_mutex_init(&synth_mutex);
 
+    ctx->export_flags |= V9FS_NO_PERF_WARN;
+
     /* Add "." and ".." entries for root */
     v9fs_add_dir_node(&synth_root, synth_root.attr->mode,
                       "..", synth_root.attr, synth_root.attr->inode);
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index 7bb994bbf2..741d222c3f 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -1353,6 +1353,15 @@ static void coroutine_fn v9fs_version(void *opaque)
         goto out;
     }
 
+    /* 8192 is the default msize of Linux clients */
+    if (s->msize <= 8192 && !(s->ctx.export_flags & V9FS_NO_PERF_WARN)) {
+        warn_report_once(
+            "9p: degraded performance: a reasonable high msize should be "
+            "chosen on client/guest side (chosen msize is <= 8192). See "
+            "https://wiki.qemu.org/Documentation/9psetup#msize for details."
+        );
+    }
+
 marshal:
     err = pdu_marshal(pdu, offset, "ds", s->msize, &version);
     if (err < 0) {