Andi Kleen <[EMAIL PROTECTED]> writes: > On Saturday 28 April 2007 19:23:55 Eric W. Biederman wrote: >> Andi Kleen <[EMAIL PROTECTED]> writes: >> >> >> My preference would be for whoever had: >> >> paravirt_ops-hooks-to-set-up-initial-pagetable.patch >> > >> > That would be very messy because there are many followup dependencies. >> > >> > But once we have a good fix aggreed by everybody I can merge it into the >> > initial patch then. >> >> I don't see Xen patches merged yet in your tree yet. > > Hmm, I thought you were talking about paravirt-initial-pagetable ?
Yes that is the patch with problems. > That one is in my tree already. The Xen patches that are still outstanding > iirc are all addons patches, as they don't impact existing code paths anymore. Ok. Right now Xen is the only paravirtualization solution that wants to make page tables read only. The current Xen methodology is to setup the identity mapping with the initial page table set to read-only, before calling paging_init(). kernel_physical_mapping_init was modified to skip pages which are already in the page table. However in other cases this causes us to fail to setup important bits like PSE and NX where we want them on the page tables. So for the leaf pages we need to continue setting things at least on real hardware. The current plan was that Jeremy was going to go and modify the Xen set_pte early in boot, to preserve to mask off _PAGE_RW in early boot for pages that don't currently have _PAGE_RW set. So the fix is two parts. - Part one unconditionally set the page table entries for 4K and pse pages. - Fix the Xen set_pte. Short of making the identity mapping setup paravirt specific I don't know what we can do. Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
