dm: don't deassign pass through PCIe device in DM

Let the ACRN HV to do this in shutdown sequence. In this case, the RTVM could be
still alive if something wrong happened to cause the DM died.

Tracked-On: #4428
Signed-off-by: Li Fei1 <fei1.li@intel.com>

Author: lifeix

devicemodel/core/main.c

@@ -686,7 +686,8 @@ vm_loop(struct vmctx *ctx)
 			break;
 		}
 
-		if (VM_SUSPEND_SYSTEM_RESET == vm_get_suspend_mode()) {
+		/* RTVM can't be reset */
+		if ((VM_SUSPEND_SYSTEM_RESET == vm_get_suspend_mode()) && (!is_rtvm)) {
 			vm_system_reset(ctx);
 		}
 

devicemodel/hw/pci/passthrough.c

@@ -45,6 +45,7 @@
 #include "pciio.h"
 #include "pci_core.h"
 #include "acpi.h"
+#include "dm.h"
 
 
 /* Some audio drivers get topology data from ACPI NHLT table.
@@ -558,7 +559,13 @@ passthru_deinit(struct vmctx *ctx, struct pci_vdev *dev, char *opts)
 	pcidev.phys_bdf = ptdev->phys_bdf;
 	pciaccess_cleanup();
 	free(ptdev);
-	vm_deassign_pcidev(ctx, &pcidev);
+
+	if (!is_rtvm) {
+		/* Let the HV to deassign the pt device for RTVM, In this case, the RTVM
+		 * could still be alive if DM died.
+		 */
+		vm_deassign_pcidev(ctx, &pcidev);
+	}
 }
 
 /* bind pin info for pass-through device */