diff options
| author | Don Slutz <dslutz@verizon.com> | 2014-06-19 21:40:25 -0400 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2014-06-23 18:02:41 +0300 |
| commit | c87b1520726f7ae1e698a41f07043d1b539ac88c (patch) | |
| tree | 401b304520238bdcc32867e977eb662b8c4cc196 /hw/i386/pc_piix.c | |
| parent | 3c2a96699e9fc09b5712dacfe200cdaaff0bb55c (diff) | |
pc & q35: Add new machine opt max-ram-below-4g
This is a pc & q35 only machine opt.
If you add enough PCI devices then all mmio for them will not fit
below 4G which may not be the layout the user wanted. This allows
you to increase the below 4G address space that PCI devices can use
(aka decrease ram below 4G) and therefore in more cases not have any
mmio that is above 4G.
For example using "-machine pc,max-ram-below-4g=2G" on the command
line will limit the amount of ram that is below 4G to 2G.
Note: this machine option cannot be used to increase the amount
of ram below 4G.
Signed-off-by: Don Slutz <dslutz@verizon.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
MST: fix 32 bit
Diffstat (limited to 'hw/i386/pc_piix.c')
| -rw-r--r-- | hw/i386/pc_piix.c | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c index 60057f9de4..47546b72ae 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 { |