[PATCH v2 4/6] x86/PV: properly set shadow allocation for Dom0

[Jan Beulich <jbeulich@xxxxxxxx>]

Leaving shadow setup just to the L1TF tasklet means running Dom0 on a
minimally acceptable shadow memory pool, rather than what normally
would be used (also, for example, for PVH). Populate the pool before
triggering the tasklet, on a best effort basis (again like done for
PVH).

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Acked-by: Tim Deegan <tim@xxxxxxx>
---
v2: Latch dom0_paging_pages() result.

--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -1298,7 +1298,7 @@ int shadow_set_allocation(struct domain
 {
     struct page_info *sp;
 
-    ASSERT(paging_locked_by_me(d));
+    ASSERT(paging_locked_by_me(d) || system_state < SYS_STATE_active);
 
     if ( pages > 0 )
     {
--- a/xen/arch/x86/pv/dom0_build.c
+++ b/xen/arch/x86/pv/dom0_build.c
@@ -21,6 +21,7 @@
 #include <asm/page.h>
 #include <asm/pv/mm.h>
 #include <asm/setup.h>
+#include <asm/shadow.h>
 
 /* Allow ring-3 access in long mode as guest cannot use ring 1 ... */
 #define BASE_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_USER)
@@ -933,7 +934,18 @@ int __init dom0_construct_pv(struct doma
 #ifdef CONFIG_SHADOW_PAGING
     if ( opt_dom0_shadow )
     {
+        bool preempted;
+
         printk("Switching dom0 to using shadow paging\n");
+
+        nr_pt_pages = dom0_paging_pages(d, nr_pages);
+
+        do {
+            preempted = false;
+            shadow_set_allocation(d, nr_pt_pages, &preempted);
+            process_pending_softirqs();
+        } while ( preempted );
+
         tasklet_schedule(&d->arch.paging.shadow.pv_l1tf_tasklet);
     }
 #endif