[PATCH QEMU HCI-8.1 17/21] vfio/listener: skip dirty page tracking during CPR

[Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>]

During cpr-transfer and cpr-exec guest RAM is preserved in place, not
copied, so there's no need to track which pages the device writes to.

Yet starting the migration also starts VFIO dirty tracking, on the
container or on the device itself (DMA logging).  With cpr-exec it isn't
stopped before exec, so e.g. the DMA page tracker of an NVIDIA vGPU is
left running after the update.

Don't start or stop dirty tracking in CPR modes.

Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
---
 hw/vfio/listener.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c
index afcf518f567..5585d656c4a 100644
--- a/hw/vfio/listener.c
+++ b/hw/vfio/listener.c
@@ -41,6 +41,7 @@
 #include "trace.h"
 #include "qapi/error.h"
 #include "migration/misc.h"
+#include "migration/cpr.h"
 #include "migration/qemu-file.h"
 #include "system/tcg.h"
 #include "system/tpm.h"
@@ -1012,6 +1013,11 @@ static bool vfio_listener_log_global_start(MemoryListener *listener,
                                              listener);
     bool ret;
 
+    /* Preserved devices keep DMA-ing into preserved RAM, nothing to track */
+    if (cpr_incoming_needed(NULL)) {
+        return true;
+    }
+
     if (vfio_container_devices_dirty_tracking_is_supported(bcontainer)) {
         ret = vfio_devices_dma_logging_start(bcontainer, errp);
     } else {
@@ -1031,6 +1037,10 @@ static void vfio_listener_log_global_stop(MemoryListener *listener)
     Error *local_err = NULL;
     int ret = 0;
 
+    if (cpr_incoming_needed(NULL)) {
+        return;
+    }
+
     if (vfio_container_devices_dirty_tracking_is_supported(bcontainer)) {
         vfio_devices_dma_logging_stop(bcontainer);
     } else {

-- 
2.47.1