[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: Re: [Xen-devel] How to create shadow page table of my own?
At 2011-02-21,"Tim Deegan" <Tim.Deegan@xxxxxxxxxx> wrote: >At 13:57 +0000 on 21 Feb (1298296632), ?????? wrote: >> I deliberately make those two sections align for the page in order to >> make SPT creation simple, see that? The sim_k_text & data all start at >> a new page. The text section occupied 13 pages & data occupied 1 page >> although the size of data is only 0x7c. > >Yes I saw that. > >> I know in the hvm, the virtual address is translated to the physical >> address first, then translated to the machine address. For my >> constructed address space, I want to create SPT to convert virtual >> address to machine address directly & eliminate the need for any guest >> level page table for this address space, is it possible? > >Sure it's possible. You can put anything you like into the shadow >pagetables. But you need first to think about _exactly_ what behaviour >you want. If two VCPUs have the same CR3 value will you ever need them >to have different shadow pagetables? That's not possible with the >current Xen shadow pagetables because they share one set of shadows >among all a domain's VCPUs. > >What should happen if Xen emulates an instruction that accesses the >secure area? The emulator doesn't use the shadow pagetables so you >will have to find and fix the other paths that map VAs to MAs. > >Have you got access to a machine that supports AMD NPT or Intel EPT? If >so it might be easier to have a per-VCPU EPT/NPT table that you add and >remove mappings as you go in and out of "secure" mode. > >> For now what I consider is pass the starting address & size to the xen. >> >> You said I need to duplicate a lot of state, where I need to modify? > >xen/arch/x86/mm/shadow/*.c . It's pretty complex code but there are >some comments in there. But as I said it would probably be easier to >use the EPT/NPT code if you can. > >Cheer, > >Tim. > >-- >Tim Deegan <Tim.Deegan@xxxxxxxxxx> >Principal Software Engineer, Xen Platform Team >Citrix Systems UK Ltd. (Company #02937203, SL9 0BG) OK, I'll have a try as you said first. Hopefully it won't take a long long time:) Thanks a lot. Have a nice day~~ _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
|
![]() |
Lists.xenproject.org is hosted with RackSpace, monitoring our |