From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zachary Amsden Subject: Re: [PATCH 4/9] Vmi fix highpte Date: Thu, 01 Mar 2007 22:24:06 -0800 Message-ID: <45E7C306.4080400@vmware.com> References: <200703020254.l222smBB009668@zach-dev.vmware.com> <45E79529.9000305@goop.org> <45E79C72.4000806@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <45E79C72.4000806@goop.org> Sender: linux-kernel-owner@vger.kernel.org To: Jeremy Fitzhardinge Cc: Chris Wright , Andi Kleen , Linus Torvalds , Andrew Morton , Virtualization Mailing List , Linux Kernel Mailing List List-Id: virtualization@lists.linuxfoundation.org Jeremy Fitzhardinge wrote: > Jeremy Fitzhardinge wrote: > >> Hm, I don't think this interface will work for Xen. In Xen, whenever a >> pagetable page gets mapped, it must be mapped RO. map_pt_hook gets >> called after the mapping has already been created, so its too late for Xen. >> >> I was planning on adding kmap_atomic_pte() for use in pte_offset_map*(), >> which would be wired through to paravirt_ops to allow Xen to make this a >> RO mapping. Would this be sufficient for you to do your vmi thing? >> >> > > Something like this (compiled, untested). > > J > > diff -r 972e84c265cf arch/i386/kernel/paravirt.c > --- a/arch/i386/kernel/paravirt.c Thu Mar 01 19:12:49 2007 -0800 > +++ b/arch/i386/kernel/paravirt.c Thu Mar 01 19:38:42 2007 -0800 > @@ -32,6 +32,7 @@ > #include > #include > #include > +#include > > /* nop stub */ > void _paravirt_nop(void) > @@ -605,6 +606,8 @@ struct paravirt_ops paravirt_ops = { > > .kpte_clear_flush = native_kpte_clear_flush, > > + .kmap_atomic_pte = native_kmap_atomic_pte, > + > That doesn't quite work, since we need to know which of the two - KM_PTE0 or KM_PTE1 is being mapped. But it could be moved to before the mapping, as you need, and take this as a parameter. Zach