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-rw-r--r--hw/i386/pc.c47
-rw-r--r--hw/i386/pc_piix.c22
-rw-r--r--hw/i386/pc_q35.c22
-rw-r--r--include/hw/i386/pc.h3
-rw-r--r--vl.c4
5 files changed, 96 insertions, 2 deletions
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 67eb450..2cf22b1 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1643,11 +1643,58 @@ pc_machine_get_hotplug_memory_region_size(Object *obj, Visitor *v, void *opaque,
visit_type_int(v, &value, name, errp);
}
+static void pc_machine_get_max_ram_below_4g(Object *obj, Visitor *v,
+ void *opaque, const char *name,
+ Error **errp)
+{
+ PCMachineState *pcms = PC_MACHINE(obj);
+ uint64_t value = pcms->max_ram_below_4g;
+
+ visit_type_size(v, &value, name, errp);
+}
+
+static void pc_machine_set_max_ram_below_4g(Object *obj, Visitor *v,
+ void *opaque, const char *name,
+ Error **errp)
+{
+ PCMachineState *pcms = PC_MACHINE(obj);
+ Error *error = NULL;
+ uint64_t value;
+
+ visit_type_size(v, &value, name, &error);
+ if (error) {
+ error_propagate(errp, error);
+ return;
+ }
+ if (value > (1ULL << 32)) {
+ error_set(&error, ERROR_CLASS_GENERIC_ERROR,
+ "Machine option 'max-ram-below-4g=%"PRIu64
+ "' expects size less than or equal to 4G", value);
+ error_propagate(errp, error);
+ return;
+ }
+
+ if (value < (1ULL << 20)) {
+ error_report("Warning: small max_ram_below_4g(%"PRIu64
+ ") less than 1M. BIOS may not work..",
+ value);
+ }
+
+ pcms->max_ram_below_4g = value;
+}
+
static void pc_machine_initfn(Object *obj)
{
+ PCMachineState *pcms = PC_MACHINE(obj);
+
object_property_add(obj, PC_MACHINE_MEMHP_REGION_SIZE, "int",
pc_machine_get_hotplug_memory_region_size,
NULL, NULL, NULL, NULL);
+ pcms->max_ram_below_4g = 1ULL << 32; /* 4G */
+ object_property_add(obj, PC_MACHINE_MAX_RAM_BELOW_4G, "size",
+ pc_machine_get_max_ram_below_4g,
+ pc_machine_set_max_ram_below_4g,
+ NULL, NULL, NULL);
}
static void pc_machine_class_init(ObjectClass *oc, void *data)
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 60057f9..47546b7 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -48,6 +48,7 @@
#include "exec/address-spaces.h"
#include "hw/acpi/acpi.h"
#include "cpu.h"
+#include "qemu/error-report.h"
#ifdef CONFIG_XEN
# include <xen/hvm/hvm_info_table.h>
#endif
@@ -98,6 +99,7 @@ static void pc_init1(MachineState *machine,
DeviceState *icc_bridge;
FWCfgState *fw_cfg = NULL;
PcGuestInfo *guest_info;
+ ram_addr_t lowmem;
/* Check whether RAM fits below 4G (leaving 1/2 GByte for IO memory).
* If it doesn't, we need to split it in chunks below and above 4G.
@@ -107,7 +109,25 @@ static void pc_init1(MachineState *machine,
* breaking migration.
*/
if (machine->ram_size >= 0xe0000000) {
- ram_addr_t lowmem = gigabyte_align ? 0xc0000000 : 0xe0000000;
+ lowmem = gigabyte_align ? 0xc0000000 : 0xe0000000;
+ } else {
+ lowmem = 0xe0000000;
+ }
+
+ /* 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 {
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index da5fd53..155db99 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
@@ -85,6 +86,7 @@ static void pc_q35_init(MachineState *machine)
PCIDevice *ahci;
DeviceState *icc_bridge;
PcGuestInfo *guest_info;
+ 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
@@ -96,7 +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 {
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 651971d..486e98f 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -33,10 +33,13 @@ struct PCMachineState {
MemoryRegion hotplug_memory;
HotplugHandler *acpi_dev;
+
+ uint64_t max_ram_below_4g;
};
#define PC_MACHINE_ACPI_DEVICE_PROP "acpi-device"
#define PC_MACHINE_MEMHP_REGION_SIZE "hotplug-memory-region-size"
+#define PC_MACHINE_MAX_RAM_BELOW_4G "max-ram-below-4g"
/**
* PCMachineClass:
diff --git a/vl.c b/vl.c
index ab8f152..194c6f7 100644
--- a/vl.c
+++ b/vl.c
@@ -381,6 +381,10 @@ static QemuOptsList qemu_machine_opts = {
.name = "kvm-type",
.type = QEMU_OPT_STRING,
.help = "Specifies the KVM virtualization mode (HV, PR)",
+ },{
+ .name = PC_MACHINE_MAX_RAM_BELOW_4G,
+ .type = QEMU_OPT_SIZE,
+ .help = "maximum ram below the 4G boundary (32bit boundary)",
},
{ /* End of list */ }
},
generated by cgit v1.1 at 2025-01-16 13:48:12 +0000