On Thu, Apr 19, 2012 at 6:56 PM, Xin Tong <xerox.time.t...@gmail.com> wrote: > On Thu, Apr 19, 2012 at 1:03 PM, Blue Swirl <blauwir...@gmail.com> wrote: >> On Thu, Apr 19, 2012 at 01:55, Xin Tong <xerox.time.t...@gmail.com> wrote: >>> but should not the address be within 1 - 4G-1 even with PAE. is not >>> the PAE just using 64bits addresses as supposed to 32 bit ? what does >>> the physical address bigger than 4G mean ? is not the physical >>> address starting from 0 from the prospective of the processor ? >> >> With 64 bit physical addresses the range can be 0 to >> 0xffffffffffffffff. Perhaps you need to read more background material, >> for example Intel or AMD processor manuals are quite extensive. >> >> Please don't top post, it breaks the natural reply order. >> >>> >>> Xin >>> >>> >>> On Wed, Apr 18, 2012 at 4:03 PM, Blue Swirl <blauwir...@gmail.com> wrote: >>>> On Wed, Apr 18, 2012 at 01:28, Xin Tong <xerox.time.t...@gmail.com> wrote: >>>>> I am reading how qemu refill TLB working. >>>>> >>>>> target-i386/helper.c >>>>> >>>>> pte = pte & env->a20_mask; >>>>> >>>>> /* Even if 4MB pages, we map only one 4KB page in the cache to >>>>> avoid filling it too fast */ >>>>> page_offset = (addr & TARGET_PAGE_MASK) & (page_size - 1); >>>>> paddr = (pte & TARGET_PAGE_MASK) + page_offset; >>>>> vaddr = virt_addr + page_offset; >>>>> >>>>> >>>>> How can the paddr be bigger than 4G even though i gave the machine >>>>> 4096 MB of memory ( i.e. qemu -m 4096 ...). should not paddr be within >>>>> 0 - 4G-1 ? >>>> >>>> No. There's PAE and the same code is used by both i386 and x86_64. >>>> >>>>> >>>>> Thanks >>>>> >>>>> Xin >>>>> > > In QEMU, the guest memory is emulated by allocating a contiguous chunk > of memory from the host machine. is the emulated memory contiguous > with respect to the host memory. i.e. memory address 0x0 of guest maps > to 0x760000000 in host and memory address 0x5000 maps to 0x760005000 > in host, etc. > > Also, what would be a good way to find this offset ? qemu_get_ram_ptr(0) ? > > Xin
Ok. this is what i want. when qemu starts, it mmaps a chunk of memory from the host as the emulated guest memory. If I am emulating more than one cpu, given a guest physical page, i want to know which cpu TLB has an entry that will translate into the guest physical page. the addr_read/addr_write + addend will give host virtual address. i want to build a core map keeping track of which TLB entries (could be in multiple emulated cpus) translates to the host page. Thanks Xin
