From f4f97b3ea90130520afb478cbc2918be2b6587b8 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Tue, 17 Jul 2007 18:37:05 -0700 Subject: xen: Complete pagetable pinning Xen requires all active pagetables to be marked read-only. When the base of the pagetable is loaded into %cr3, the hypervisor validates the entire pagetable and only allows the load to proceed if it all checks out. This is pretty slow, so to mitigate this cost Xen has a notion of pinned pagetables. Pinned pagetables are pagetables which are considered to be active even if no processor's cr3 is pointing to is. This means that it must remain read-only and all updates are validated by the hypervisor. This makes context switches much cheaper, because the hypervisor doesn't need to revalidate the pagetable each time. This also adds a new paravirt hook which is called during setup once the zones and memory allocator have been initialized. When the init_mm pagetable is first built, the struct page array does not yet exist, and so there's nowhere to put he init_mm pagetable's PG_pinned flags. Once the zones are initialized and the struct page array exists, we can set the PG_pinned flags for those pages. This patch also adds the Xen support for pte pages allocated out of highmem (highpte) by implementing xen_kmap_atomic_pte. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Chris Wright Cc: Zach Amsden --- arch/i386/xen/xen-ops.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/i386/xen/xen-ops.h') diff --git a/arch/i386/xen/xen-ops.h b/arch/i386/xen/xen-ops.h index 79648fe1ab77..54d98b52085e 100644 --- a/arch/i386/xen/xen-ops.h +++ b/arch/i386/xen/xen-ops.h @@ -20,6 +20,8 @@ unsigned long xen_get_wallclock(void); int xen_set_wallclock(unsigned long time); cycle_t xen_clocksource_read(void); +void xen_mark_init_mm_pinned(void); + DECLARE_PER_CPU(enum paravirt_lazy_mode, xen_lazy_mode); static inline unsigned xen_get_lazy_mode(void) -- cgit v1.2.3