[Qemu-devel] [Qemu devel] Question: Qemu support up to 4GB physical memory?

[Qemu-devel] [Qemu devel] Question: Qemu support up to 4GB physical memory?

[wuxi]

Hi, all:
I am hacking QEMU (for a course project) based on the 0.10.1 version on 
x86-64 architecture. My question arises when I was checking the code of 
PageDesc in QEMU. I found it uses a two level mapping (l1_map), and it 
seems that QEMU can support physical memory up to   210 * 210 * (4KB) = 
4GB.

the related code is:

(L1_BITS = 10, L2_BITS=10, TARGET_PAGE_BITS=12)

#define L1_BITS (32 - L2_BITS - TARGET_PAGE_BITS)
#define L1_SIZE (1 << L1_BITS)
#define L2_SIZE (1 << L2_BITS)

static PageDesc *l1_map[L1_SIZE];

p = qemu_mallocz(sizeof(PageDesc) * L2_SIZE); (for each l1_map entry)

Is this true for QEMU x86-64 emulation? or I made some silly mistakes...

Thanks !

yours sincerely

Andrew

[Qemu-devel] Question: Qemu support up to 4GB physical memory?

[吴曦]

Hi, all:
I am hacking QEMU (for a course project) based on the 0.10.1 version
on x86-64 architecture. My question arises when I was checking the
code of PageDesc in QEMU. I found it uses a two level mapping
(l1_map), and it seems that QEMU can support physical memory up to
210 * 210 * (4KB) = 4GB.

the related code is:

(L1_BITS = 10, L2_BITS=10, TARGET_PAGE_BITS=12)

#define L1_BITS (32 - L2_BITS - TARGET_PAGE_BITS)
#define L1_SIZE (1 << L1_BITS)
#define L2_SIZE (1 << L2_BITS)

static PageDesc *l1_map[L1_SIZE];

p = qemu_mallocz(sizeof(PageDesc) * L2_SIZE); (for each l1_map entry)

Is this true for QEMU x86-64 emulation? or I made some silly mistakes...

Thanks !

yours sincerely

Andrew