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From: | Wenjie Liu |
Subject: | Re: [Qemu-devel] About address mapping between host and guest in QEMU |
Date: | Thu, 23 Apr 2015 21:56:31 +0800 |
In http://vm-kernel.org/blog/2009/07/10/qemu-internal-part-2-softmmu/, the following equation is mentioned.host_virtual_address = phys_ram_base(qemu variable) + guest_physical_address – guest_physical_address_base(0 in MIPS)I think I have got the phys_ram_base and guest_physical_address, but can anybody tell me what is guest_physical_address_base?I saw the memory allocation part in qemu/pc/pc.c:/* allocate RAM */ram_addr = qemu_ram_alloc(NULL, "pc.ram",below_4g_mem_size + above_4g_mem_size);cpu_register_physical_memory(0, 0xa0000, ram_addr);cpu_register_physical_memory(0x100000,below_4g_mem_size - 0x100000,ram_addr + 0x100000);#if TARGET_PHYS_ADDR_BITS > 32if (above_4g_mem_size > 0) {cpu_register_physical_memory(0x100000000ULL, above_4g_mem_size,ram_addr + below_4g_mem_size);}#endifI think the 0x100000, 0xa0000 and 0x100000000ULL have some relation with the guest_physical_address_base.Is that so?--2015-04-22 21:31 GMT+08:00 Wenjie Liu <address@hidden>:Hi all,I have a little problem about the address mapping between host and guest in QEMU.I have got the guest physical address and the host virtual base address of guest's memory space which by check the ramblocks list.So, can I access to the guest's memory content by simply add the guest physical address with the base?For example, if the guest physical address of a guest memory request is 0x000000011f9ff000, and the host virtual base is 0x00007f37ef122000, I am going to access the host virtual address 0x000000011f9ff000 + 0x00007f37ef122000.Is this correct?--Best regards
Best regards from
Wenjie Liu
TEL: (+86)132 9723 0518
E-mail: address@hidden
Wuhan National Laboratory for Optoelectronics,
Huazhong University of Science&Technology,
1037 Luoyu Road Wuhan, Hubei,P.R.C, 430074.
Best regards from
Wenjie Liu
TEL: (+86)132 9723 0518
E-mail: address@hidden
Wuhan National Laboratory for Optoelectronics,
Huazhong University of Science&Technology,
1037 Luoyu Road Wuhan, Hubei,P.R.C, 430074.
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