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[v2,43/86] hw/hppa/machine: Map the PDC memory region with higher priority

Message ID 1579100861-73692-44-git-send-email-imammedo@redhat.com
State New
Headers show
Series refactor main RAM allocation to use hostmem backend | expand

Commit Message

Igor Mammedov Jan. 15, 2020, 3:06 p.m. UTC 
From: Philippe Mathieu-Daudé <f4bug@amsat.org>

The region in range [0xf0000000 - 0xf1000000] is the PDC area
(Processor Dependent Code), where the firmware is loaded.
This region has higher priority than the main memory.

When the machine has more than 3840MB of RAM, there is an
overlap. Since the PDC is closer to the CPU in the bus
hierarchy, it gets accessed first, and the CPU does not have
access to the RAM in this range.

To model the same behavior and keep a simple memory layout,
reduce the priority of the RAM region. The PDC region ends
overlapping the RAM.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
 hw/hppa/machine.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/hw/hppa/machine.c b/hw/hppa/machine.c
index 119ae4d..810e671 100644
--- a/hw/hppa/machine.c
+++ b/hw/hppa/machine.c
@@ -98,7 +98,7 @@  static void machine_hppa_init(MachineState *machine)
     ram_region = g_new(MemoryRegion, 1);
     memory_region_allocate_system_memory(ram_region, OBJECT(machine),
                                          "ram", ram_size);
-    memory_region_add_subregion(addr_space, 0, ram_region);
+    memory_region_add_subregion_overlap(addr_space, 0, ram_region, -1);
 
     /* Init Dino (PCI host bus chip).  */
     pci_bus = dino_init(addr_space, &rtc_irq, &serial_irq);