libs/guest: Set console as disconnected on resume

There is currently an asymmetry between HVM where the page is cleared
and PV where the contents are restored.

Add xc_dom_console_set_disconnected() to only set the connection flag
for PV guests.

xenconsoled is responsible for setting the console connected when it
attaches.

Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Release-Acked-By: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Acked-by: Anthony PERARD <anthony.perard@vates.tech>

tools/include/xenguest.h

@@ -337,6 +337,8 @@ int xc_dom_boot_image(struct xc_dom_image *dom);
 int xc_dom_compat_check(struct xc_dom_image *dom);
 int xc_dom_console_init(xc_interface *xch, uint32_t guest_domid,
                         xen_pfn_t console_gfn);
+int xc_dom_console_set_disconnected(xc_interface *xch, uint32_t guest_domid,
+                                    xen_pfn_t console_gfn);
 int xc_dom_gnttab_init(struct xc_dom_image *dom);
 int xc_dom_gnttab_seed(xc_interface *xch, uint32_t guest_domid,
                        bool is_hvm,

tools/libs/guest/xg_dom_boot.c

@@ -428,9 +428,10 @@ int xc_dom_gnttab_init(struct xc_dom_image *dom)
                               dom->console_domid, dom->xenstore_domid);
 }
 
-int xc_dom_console_init(xc_interface *xch,
-                        uint32_t domid,
-                        unsigned long dst_pfn)
+static int dom_console_init(xc_interface *xch,
+                            uint32_t domid,
+                            unsigned long dst_pfn,
+                            bool clear)
 {
     const size_t size = PAGE_SIZE;
     struct xencons_interface *xencons = xc_map_foreign_range(
@@ -439,7 +440,8 @@ int xc_dom_console_init(xc_interface *xch,
     if ( xencons == NULL )
         return -1;
 
-    memset(xencons, 0, size);
+    if (clear)
+        memset(xencons, 0, size);
     xencons->connection = XENCONSOLE_DISCONNECTED;
 
     munmap(xencons, size);
@@ -447,6 +449,20 @@ int xc_dom_console_init(xc_interface *xch,
     return 0;
 }
 
+int xc_dom_console_init(xc_interface *xch,
+                        uint32_t domid,
+                        unsigned long dst_pfn)
+{
+    return dom_console_init(xch, domid, dst_pfn, true);
+}
+
+int xc_dom_console_set_disconnected(xc_interface *xch,
+                                    uint32_t domid,
+                                    unsigned long dst_pfn)
+{
+    return dom_console_init(xch, domid, dst_pfn, false);
+}
+
 /*
  * Local variables:
  * mode: C

tools/libs/guest/xg_sr_restore_x86_hvm.c

@@ -62,7 +62,7 @@ static int handle_hvm_params(struct xc_sr_context *ctx,
         {
         case HVM_PARAM_CONSOLE_PFN:
             ctx->restore.console_gfn = entry->value;
-            xc_clear_domain_page(xch, ctx->domid, entry->value);
+            xc_dom_console_init(xch, ctx->domid, entry->value);
             break;
         case HVM_PARAM_STORE_PFN:
             ctx->restore.xenstore_gfn = entry->value;

tools/libs/guest/xg_sr_restore_x86_pv.c

@@ -208,6 +208,7 @@ static int process_start_info(struct xc_sr_context *ctx,
         goto err;
     }
 
+    xc_dom_console_set_disconnected(xch, ctx->domid, mfn);
     ctx->restore.console_gfn = mfn;
     SET_FIELD(guest_start_info, console.domU.mfn, mfn, ctx->x86.pv.width);
     SET_FIELD(guest_start_info, console.domU.evtchn,