Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 15 Jun 2015 22:35:32 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 07/12] x86/virt/guest/xen: Remove use of pgd_list from the Xen guest code |
| |
* David Vrabel <david.vrabel@citrix.com> wrote:
> On 15/06/15 10:05, Ian Campbell wrote: > > On Sat, 2015-06-13 at 11:49 +0200, Ingo Molnar wrote:
> >> xen_mm_pin_all()/unpin_all() are used to implement full guest instance > >> suspend/restore. It's a stop-all method that needs to iterate through all > >> allocated pgds in the system to fix them up for Xen's use. > >> > >> This code uses pgd_list, probably because it was an easy interface. > >> > >> But we want to remove the pgd_list, so convert the code over to walk all > >> tasks in the system. This is an equivalent method. > > It is not equivalent because pgd_alloc() now populates entries in pgds that are > not visible to xen_mm_pin_all() (note how the original code adds the pgd to the > pgd_list in pgd_ctor() before calling pgd_prepopulate_pmd()). These newly > allocated page tables won't be correctly converted on suspend/resume and the new > process will die after resume.
So how should the Xen logic be fixed for the new scheme? I can't say I can see through the paravirt complexity here.
Thanks,
Ingo
| ![\](/images/icornerr.gif) |