[PATCH] i386: PARAVIRT: add kmap_atomic_pte for mapping highpte pages
Xen and VMI both have special requirements when mapping a highmem pte
page into the kernel address space. These can be dealt with by adding
a new kmap_atomic_pte() function for mapping highptes, and hooking it
into the paravirt_ops infrastructure.
Xen specifically wants to map the pte page RO, so this patch exposes a
helper function, kmap_atomic_prot, which maps the page with the
specified page protections.
This also adds a kmap_flush_unused() function to clear out the cached
kmap mappings. Xen needs this to clear out any potential stray RW
mappings of pages which will become part of a pagetable.
[ Zach - vmi.c will need some attention after this patch. It wasn't
immediately obvious to me what needs to be done. ]
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Zachary Amsden <zach@vmware.com>
diff --git a/include/asm-i386/paravirt.h b/include/asm-i386/paravirt.h
index 10f44af..5048b41 100644
--- a/include/asm-i386/paravirt.h
+++ b/include/asm-i386/paravirt.h
@@ -16,7 +16,9 @@
#ifndef __ASSEMBLY__
#include <linux/types.h>
#include <linux/cpumask.h>
+#include <asm/kmap_types.h>
+struct page;
struct thread_struct;
struct Xgt_desc_struct;
struct tss_struct;
@@ -187,6 +189,10 @@
pte_t (*ptep_get_and_clear)(pte_t *ptep);
+#ifdef CONFIG_HIGHPTE
+ void *(*kmap_atomic_pte)(struct page *page, enum km_type type);
+#endif
+
#ifdef CONFIG_X86_PAE
void (*set_pte_atomic)(pte_t *ptep, pte_t pteval);
void (*set_pte_present)(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte);
@@ -884,6 +890,15 @@
PVOP_VCALL1(release_pd, pfn);
}
+#ifdef CONFIG_HIGHPTE
+static inline void *kmap_atomic_pte(struct page *page, enum km_type type)
+{
+ unsigned long ret;
+ ret = PVOP_CALL2(unsigned long, kmap_atomic_pte, page, type);
+ return (void *)ret;
+}
+#endif
+
static inline void pte_update(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{