[PATCH 06/15] x86/PVH: keep a copy of Dom0's initial E820 map

[Jan Beulich <jbeulich@xxxxxxxx>]

pvh_populate_p2m() needs to populate RAM according to the initial map
established, prior to any stealing by pvh_steal_ram(). Subsequently the
invocations of those functions will (need to) move ahead of
pvh_populate_p2m(), so what to act on is no longer Dom0's memory map at
the time of invocation.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/hvm/dom0_build.c
+++ b/xen/arch/x86/hvm/dom0_build.c
@@ -13,6 +13,7 @@
 #include <xen/multiboot.h>
 #include <xen/pci.h>
 #include <xen/softirq.h>
+#include <xen/xvmalloc.h>
 
 #include <acpi/actables.h>
 
@@ -413,7 +414,10 @@ static void __init pvh_init_p2m(struct d
     } while ( preempted );
 }
 
-static int __init pvh_populate_p2m(struct domain *d)
+static int __init pvh_populate_p2m(
+    struct domain *d,
+    const struct e820entry *e820,
+    unsigned int nr_e820)
 {
     struct vcpu *v = d->vcpu[0];
     unsigned int i;
@@ -421,15 +425,15 @@ static int __init pvh_populate_p2m(struc
 #define MB1_PAGES PFN_DOWN(MB(1))
 
     /* Populate memory map. */
-    for ( i = 0; i < d->arch.nr_e820; i++ )
+    for ( i = 0; i < nr_e820; i++ )
     {
         unsigned long addr, size;
 
-        if ( d->arch.e820[i].type != E820_RAM )
+        if ( e820[i].type != E820_RAM )
             continue;
 
-        addr = PFN_DOWN(d->arch.e820[i].addr);
-        size = PFN_DOWN(d->arch.e820[i].size);
+        addr = PFN_DOWN(e820[i].addr);
+        size = PFN_DOWN(e820[i].size);
 
         rc = pvh_populate_memory_range(d, addr, size);
         if ( rc )
@@ -438,11 +442,11 @@ static int __init pvh_populate_p2m(struc
         if ( addr < MB1_PAGES )
         {
             uint64_t end = min_t(uint64_t, MB(1),
-                                 d->arch.e820[i].addr + d->arch.e820[i].size);
+                                 e820[i].addr + e820[i].size);
             enum hvm_translation_result res =
                  hvm_copy_to_guest_phys(mfn_to_maddr(_mfn(addr)),
                                         mfn_to_virt(addr),
-                                        end - d->arch.e820[i].addr,
+                                        end - e820[i].addr,
                                         v);
 
             if ( res != HVMTRANS_okay )
@@ -1352,6 +1356,8 @@ int __init dom0_construct_pvh(const stru
     paddr_t entry, start_info;
     struct domain *d = bd->d;
     struct elf_binary elf;
+    struct e820entry *orig_e820;
+    unsigned int nr_orig_e820;
     int rc;
 
     printk(XENLOG_INFO "*** Building a PVH Dom%d ***\n", d->domain_id);
@@ -1389,6 +1395,15 @@ int __init dom0_construct_pvh(const stru
 
     iommu_hwdom_init(d);
 
+    nr_orig_e820 = d->arch.nr_e820;
+    orig_e820 = xvmalloc_array(struct e820entry, nr_orig_e820);
+    if ( !orig_e820 )
+    {
+        printk("No memory for copy of E820 map (%u entries)\n", nr_orig_e820);
+        return -ENOMEM;
+    }
+    memcpy(orig_e820, d->arch.e820, nr_orig_e820 * sizeof(*orig_e820));
+
     rc = pvh_place_kernel(bd, &elf, &entry);
     if ( rc )
     {
@@ -1396,13 +1411,15 @@ int __init dom0_construct_pvh(const stru
         return rc;
     }
 
-    rc = pvh_populate_p2m(d);
+    rc = pvh_populate_p2m(d, orig_e820, nr_orig_e820);
     if ( rc )
     {
         printk("Failed to setup Dom0 physical memory map\n");
         return rc;
     }
 
+    xvfree(orig_e820);
+
     rc = pvh_load_kernel(bd, &elf, &start_info);
     if ( rc )
     {