1 files changed, 37 insertions, 16 deletions

diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index aa71332ee1..155db99f63 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -44,6 +44,7 @@
 #include "hw/ide/ahci.h"
 #include "hw/usb.h"
 #include "hw/cpu/icc_bus.h"
+#include "qemu/error-report.h"
 
 /* ICH9 AHCI has 6 ports */
 #define MAX_SATA_PORTS     6
@@ -85,20 +86,7 @@ static void pc_q35_init(MachineState *machine)
     PCIDevice *ahci;
     DeviceState *icc_bridge;
     PcGuestInfo *guest_info;
-
-    if (xen_enabled() && xen_hvm_init(&ram_memory) != 0) {
-        fprintf(stderr, "xen hardware virtual machine initialisation failed\n");
-        exit(1);
-    }
-
-    icc_bridge = qdev_create(NULL, TYPE_ICC_BRIDGE);
-    object_property_add_child(qdev_get_machine(), "icc-bridge",
-                              OBJECT(icc_bridge), NULL);
-
-    pc_cpus_init(machine->cpu_model, icc_bridge);
-    pc_acpi_init("q35-acpi-dsdt.aml");
-
-    kvmclock_create();
+    ram_addr_t lowmem;
 
     /* Check whether RAM fits below 4G (leaving 1/2 GByte for IO memory
      * and 256 Mbytes for PCI Express Enhanced Configuration Access Mapping
@@ -110,7 +98,25 @@ static void pc_q35_init(MachineState *machine)
      * breaking migration.
      */
     if (machine->ram_size >= 0xb0000000) {
-        ram_addr_t lowmem = gigabyte_align ? 0x80000000 : 0xb0000000;
+        lowmem = gigabyte_align ? 0x80000000 : 0xb0000000;
+    } else {
+        lowmem = 0xb0000000;
+    }
+
+    /* Handle the machine opt max-ram-below-4g.  It is basicly doing
+     * min(qemu limit, user limit).
+     */
+    if (lowmem > pc_machine->max_ram_below_4g) {
+        lowmem = pc_machine->max_ram_below_4g;
+        if (machine->ram_size - lowmem > lowmem &&
+            lowmem & ((1ULL << 30) - 1)) {
+            error_report("Warning: Large machine and max_ram_below_4g(%"PRIu64
+                         ") not a multiple of 1G; possible bad performance.",
+                         pc_machine->max_ram_below_4g);
+        }
+    }
+
+    if (machine->ram_size >= lowmem) {
         above_4g_mem_size = machine->ram_size - lowmem;
         below_4g_mem_size = lowmem;
     } else {
@@ -118,6 +124,21 @@ static void pc_q35_init(MachineState *machine)
         below_4g_mem_size = machine->ram_size;
     }
 
+    if (xen_enabled() && xen_hvm_init(&below_4g_mem_size, &above_4g_mem_size,
+                                      &ram_memory) != 0) {
+        fprintf(stderr, "xen hardware virtual machine initialisation failed\n");
+        exit(1);
+    }
+
+    icc_bridge = qdev_create(NULL, TYPE_ICC_BRIDGE);
+    object_property_add_child(qdev_get_machine(), "icc-bridge",
+                              OBJECT(icc_bridge), NULL);
+
+    pc_cpus_init(machine->cpu_model, icc_bridge);
+    pc_acpi_init("q35-acpi-dsdt.aml");
+
+    kvmclock_create();
+
     /* pci enabled */
     if (pci_enabled) {
         pci_memory = g_new(MemoryRegion, 1);
@@ -388,7 +409,7 @@ static QEMUMachine pc_q35_machine_v1_4 = {
     .name = "pc-q35-1.4",
     .init = pc_q35_init_1_4,
     .compat_props = (GlobalProperty[]) {
-        PC_COMPAT_1_4,
+        PC_Q35_COMPAT_1_4,
         { /* end of list */ }
     },
 };