[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] Optimizing x86-64 xenlinux using global pages for user mode (take 2)
On 30/8/06 7:43 am, "Nakajima, Jun" <jun.nakajima@xxxxxxxxx> wrote: > The previous patch had a problem with the builder, which constructs the > initial page tables with the USER bit on. And Xen couldn't distinguish > kernel or use pages. It was partially checked avoiding the bug, and it's > finished with this patch. I'd like to avoid awareness of the extra PAGE_GUEST_KERNEL bit in guests and tools as much as possible (in fact, entirely would be good). There's no need for all the PAGE_KERNEL macros in Linux to include the new flag. The absence of PAGE_USER will suffice to allow Xen to distinguish kernel entries from user entries. All that is necessary is for Xen to add the flag when it adds PAGE_USER to a kernel entry, so that kernel entries remain disambiguated from user entries. Also, you should use one of the high-order available bits (one of bits 52-60). Other OSes use the low-order available bits for their own purposes -- we may as well avoid conflicting with them. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |