libxl/PCI: establish per-device reserved memory policy earlier

Reserved device memory region processing as well as E820 table creation
happen earlier than the adding of (PCI) devices, yet they consume the
policy (e.g. to decide whether to add entries to the E820 table). But so
far it was only at the stage of PCI device addition that the final
policy was established (i.e. if not explicitly specified by the guest
config file).

Note that I couldn't find the domain ID to be available in
libxl__domain_device_construct_rdm(), but observing that
libxl__device_pci_setdefault() also doesn't use it, for the time being
DOMID_INVALID gets passed. An obvious alternative would be to drop the
unused parameter/argument, yet at that time the question would be
whether to also drop other unused ones.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Wei Liu <wl@xen.org>

tools/libxl/libxl_dm.c

@@ -488,6 +488,11 @@ int libxl__domain_device_construct_rdm(libxl__gc *gc,
 
         assert(xrdm);
 
+        rc = libxl__device_pci_setdefault(gc, DOMID_INVALID,
+                                          &d_config->pcidevs[i], false);
+        if (rc)
+            goto out;
+
         for (n = 0; n < nr_entries; ++n) {
             bool new = true;
 

tools/libxl/libxl_internal.h

@@ -1709,6 +1709,8 @@ _hidden void libxl__device_pci_add(libxl__egc *egc, uint32_t domid,
                                    libxl__ao_device *aodev);
 _hidden void libxl__device_pci_destroy_all(libxl__egc *egc, uint32_t domid,
                                            libxl__multidev *);
+_hidden int libxl__device_pci_setdefault(libxl__gc *gc, uint32_t domid,
+                                         libxl_device_pci *pci, bool hotplug);
 _hidden bool libxl__is_igd_vga_passthru(libxl__gc *gc,
                                         const libxl_domain_config *d_config);
 

tools/libxl/libxl_pci.c

@@ -1483,8 +1483,8 @@ static int libxl__device_pci_reset(libxl__gc *gc, unsigned int domain, unsigned
     return -1;
 }
 
-static int libxl__device_pci_setdefault(libxl__gc *gc, uint32_t domid,
-                                        libxl_device_pci *pci, bool hotplug)
+int libxl__device_pci_setdefault(libxl__gc *gc, uint32_t domid,
+                                 libxl_device_pci *pci, bool hotplug)
 {
     /* We'd like to force reserve rdm specific to a device by default.*/
     if (pci->rdm_policy == LIBXL_RDM_RESERVE_POLICY_INVALID)