[Qemu-devel] [PATCH v6 3/3] xen-hvm: Pass is_default to xen_hvm_init

[Don Slutz <dslutz@verizon.com>]

This is the xen part of "pc & q35: Add new machine opt max-ram-below-4g"

This is done by adding a counter to know how many times
pc_machine_set_max_ram_below_4g() is called.  Therefore xen can know
if a non-default setting is requested.

Signed-off-by: Don Slutz <dslutz@verizon.com>
---
v6:
    Changed to work with the changes in #2:
      Added max_ram_below_4g_changed in order to know if it is a default value
      or a user specified one.
    Added "assert(pc_machine->max_ram_below_4g_changed > 0)" so that
      "make check" will abort on default not set for any of the pc or
      q35 machine types.
    Dropped "Acked-by: Stefano Stabellin" do to bigger change.

 hw/i386/pc.c         |  1 +
 hw/i386/pc_piix.c    |  2 ++
 hw/i386/pc_q35.c     |  2 ++
 include/hw/i386/pc.h |  1 +
 include/hw/xen/xen.h |  2 +-
 xen-hvm-stub.c       |  2 +-
 xen-hvm.c            | 36 ++++++++++++++++++++----------------
 7 files changed, 28 insertions(+), 18 deletions(-)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index a7f4f17..fc7e211 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1685,6 +1685,7 @@ static void pc_machine_set_max_ram_below_4g(Object *obj, Visitor *v,
     }
 
     pcms->max_ram_below_4g = value;
+    pcms->max_ram_below_4g_changed++;
 }
 
 static void pc_machine_initfn(Object *obj)
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 200c225..6072aec 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -129,7 +129,9 @@ static void pc_init1(MachineState *machine,
         below_4g_mem_size = machine->ram_size;
     }
 
+    assert(pc_machine->max_ram_below_4g_changed > 0);
     if (xen_enabled() && xen_hvm_init(&below_4g_mem_size, &above_4g_mem_size,
+                                      pc_machine->max_ram_below_4g_changed == 1,
                                       &ram_memory) != 0) {
         fprintf(stderr, "xen hardware virtual machine initialisation failed\n");
         exit(1);
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 43365cb..9386e44 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -118,7 +118,9 @@ static void pc_q35_init(MachineState *machine)
         below_4g_mem_size = machine->ram_size;
     }
 
+    assert(pc_machine->max_ram_below_4g_changed > 0);
     if (xen_enabled() && xen_hvm_init(&below_4g_mem_size, &above_4g_mem_size,
+                                      pc_machine->max_ram_below_4g_changed == 1,
                                       &ram_memory) != 0) {
         fprintf(stderr, "xen hardware virtual machine initialisation failed\n");
         exit(1);
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index f5672ee..34e488a 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -35,6 +35,7 @@ struct PCMachineState {
     HotplugHandler *acpi_dev;
 
     uint64_t max_ram_below_4g;
+    uint32_t max_ram_below_4g_changed;
 };
 
 #define PC_MACHINE_ACPI_DEVICE_PROP "acpi-device"
diff --git a/include/hw/xen/xen.h b/include/hw/xen/xen.h
index f71f2d8..6b94c14 100644
--- a/include/hw/xen/xen.h
+++ b/include/hw/xen/xen.h
@@ -41,7 +41,7 @@ void xenstore_store_pv_console_info(int i, struct CharDriverState *chr);
 
 #if defined(NEED_CPU_H) && !defined(CONFIG_USER_ONLY)
 int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size,
-                 MemoryRegion **ram_memory);
+                 bool is_default, MemoryRegion **ram_memory);
 void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size,
                    struct MemoryRegion *mr);
 void xen_modified_memory(ram_addr_t start, ram_addr_t length);
diff --git a/xen-hvm-stub.c b/xen-hvm-stub.c
index 2d98696..d1bdb76 100644
--- a/xen-hvm-stub.c
+++ b/xen-hvm-stub.c
@@ -52,7 +52,7 @@ void xen_modified_memory(ram_addr_t start, ram_addr_t length)
 }
 
 int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size,
-                 MemoryRegion **ram_memory)
+                 bool is_default, MemoryRegion **ram_memory)
 {
     return 0;
 }
diff --git a/xen-hvm.c b/xen-hvm.c
index a0b6b5d..fba2c92 100644
--- a/xen-hvm.c
+++ b/xen-hvm.c
@@ -156,31 +156,34 @@ qemu_irq *xen_interrupt_controller_init(void)
 /* Memory Ops */
 
 static void xen_ram_init(ram_addr_t *below_4g_mem_size,
-                         ram_addr_t *above_4g_mem_size,
+                         ram_addr_t *above_4g_mem_size, bool is_default,
                          ram_addr_t ram_size, MemoryRegion **ram_memory_p)
 {
     MemoryRegion *sysmem = get_system_memory();
     ram_addr_t block_len;
 
-    block_len = ram_size;
-    if (ram_size >= HVM_BELOW_4G_RAM_END) {
-        /* Xen does not allocate the memory continuously, and keep a hole at
-         * HVM_BELOW_4G_MMIO_START of HVM_BELOW_4G_MMIO_LENGTH
+    if (is_default) {
+        if (ram_size >= HVM_BELOW_4G_RAM_END) {
+            *above_4g_mem_size = ram_size - HVM_BELOW_4G_RAM_END;
+            *below_4g_mem_size = HVM_BELOW_4G_RAM_END;
+        } else {
+            *above_4g_mem_size = 0;
+            *below_4g_mem_size = ram_size;
+        }
+    }
+    if (!*above_4g_mem_size) {
+        block_len = ram_size;
+    } else {
+        /*
+         * Xen does not allocate the memory continuously, it keeps a
+         * hole of the size computed above or passed in.
          */
-        block_len += HVM_BELOW_4G_MMIO_LENGTH;
+        block_len = (1ULL << 32) + *above_4g_mem_size;
     }
     memory_region_init_ram(&ram_memory, NULL, "xen.ram", block_len);
     *ram_memory_p = &ram_memory;
     vmstate_register_ram_global(&ram_memory);
 
-    if (ram_size >= HVM_BELOW_4G_RAM_END) {
-        *above_4g_mem_size = ram_size - HVM_BELOW_4G_RAM_END;
-        *below_4g_mem_size = HVM_BELOW_4G_RAM_END;
-    } else {
-        *above_4g_mem_size = 0;
-        *below_4g_mem_size = ram_size;
-    }
-
     memory_region_init_alias(&ram_640k, NULL, "xen.ram.640k",
                              &ram_memory, 0, 0xa0000);
     memory_region_add_subregion(sysmem, 0, &ram_640k);
@@ -962,7 +965,7 @@ static void xen_wakeup_notifier(Notifier *notifier, void *data)
 }
 
 int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size,
-                 MemoryRegion **ram_memory)
+                 bool is_default, MemoryRegion **ram_memory)
 {
     int i, rc;
     unsigned long ioreq_pfn;
@@ -1040,7 +1043,8 @@ int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size,
 
     /* Init RAM management */
     xen_map_cache_init(xen_phys_offset_to_gaddr, state);
-    xen_ram_init(below_4g_mem_size, above_4g_mem_size, ram_size, ram_memory);
+    xen_ram_init(below_4g_mem_size, above_4g_mem_size, is_default, ram_size,
+                 ram_memory);
 
     qemu_add_vm_change_state_handler(xen_hvm_change_state_handler, state);
 
-- 
1.8.4