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-rw-r--r--arch/x86/include/asm/xen/page.h4
-rw-r--r--arch/x86/xen/p2m.c49
-rw-r--r--drivers/xen/grant-table.c16
3 files changed, 60 insertions, 9 deletions
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 50f0a0f6bd6a..f25bdf238a33 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -42,8 +42,8 @@ extern unsigned int machine_to_phys_order;
extern unsigned long get_phys_to_machine(unsigned long pfn);
extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn);
-extern void m2p_add_override(unsigned long mfn, struct page *page);
-extern void m2p_remove_override(struct page *page);
+extern int m2p_add_override(unsigned long mfn, struct page *page);
+extern int m2p_remove_override(struct page *page);
extern struct page *m2p_find_override(unsigned long mfn);
extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index b3b19d43b951..40d51225ff08 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -29,6 +29,7 @@
#include <linux/module.h>
#include <linux/list.h>
#include <linux/hash.h>
+#include <linux/sched.h>
#include <asm/cache.h>
#include <asm/setup.h>
@@ -404,34 +405,74 @@ static unsigned long mfn_hash(unsigned long mfn)
}
/* Add an MFN override for a particular page */
-void m2p_add_override(unsigned long mfn, struct page *page)
+int m2p_add_override(unsigned long mfn, struct page *page)
{
unsigned long flags;
- unsigned long pfn = page_to_pfn(page);
+ unsigned long pfn;
+ unsigned long address;
+ unsigned level;
+ pte_t *ptep = NULL;
+
+ pfn = page_to_pfn(page);
+ if (!PageHighMem(page)) {
+ address = (unsigned long)__va(pfn << PAGE_SHIFT);
+ ptep = lookup_address(address, &level);
+
+ if (WARN(ptep == NULL || level != PG_LEVEL_4K,
+ "m2p_add_override: pfn %lx not mapped", pfn))
+ return -EINVAL;
+ }
+
page->private = mfn;
page->index = pfn_to_mfn(pfn);
__set_phys_to_machine(pfn, FOREIGN_FRAME(mfn));
+ if (!PageHighMem(page))
+ /* Just zap old mapping for now */
+ pte_clear(&init_mm, address, ptep);
+
spin_lock_irqsave(&m2p_override_lock, flags);
list_add(&page->lru, &m2p_overrides[mfn_hash(mfn)]);
spin_unlock_irqrestore(&m2p_override_lock, flags);
+
+ return 0;
}
-void m2p_remove_override(struct page *page)
+int m2p_remove_override(struct page *page)
{
unsigned long flags;
unsigned long mfn;
unsigned long pfn;
+ unsigned long address;
+ unsigned level;
+ pte_t *ptep = NULL;
pfn = page_to_pfn(page);
mfn = get_phys_to_machine(pfn);
if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT))
- return;
+ return -EINVAL;
+
+ if (!PageHighMem(page)) {
+ address = (unsigned long)__va(pfn << PAGE_SHIFT);
+ ptep = lookup_address(address, &level);
+
+ if (WARN(ptep == NULL || level != PG_LEVEL_4K,
+ "m2p_remove_override: pfn %lx not mapped", pfn))
+ return -EINVAL;
+ }
spin_lock_irqsave(&m2p_override_lock, flags);
list_del(&page->lru);
spin_unlock_irqrestore(&m2p_override_lock, flags);
__set_phys_to_machine(pfn, page->index);
+
+ if (!PageHighMem(page))
+ set_pte_at(&init_mm, address, ptep,
+ pfn_pte(pfn, PAGE_KERNEL));
+ /* No tlb flush necessary because the caller already
+ * left the pte unmapped. */
+
+ return 0;
}
struct page *m2p_find_override(unsigned long mfn)
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 1afd5690858c..9ef54ebc1194 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -455,6 +455,8 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
unsigned long mfn;
ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
+ if (ret)
+ return ret;
for (i = 0; i < count; i++) {
/* m2p override only supported for GNTMAP_contains_pte mappings */
@@ -463,7 +465,9 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
(map_ops[i].host_addr & ~PAGE_MASK));
mfn = pte_mfn(*pte);
- m2p_add_override(mfn, pages[i]);
+ ret = m2p_add_override(mfn, pages[i]);
+ if (ret)
+ return ret;
}
return ret;
@@ -476,8 +480,14 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
int i, ret;
ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
- for (i = 0; i < count; i++)
- m2p_remove_override(pages[i]);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < count; i++) {
+ ret = m2p_remove_override(pages[i]);
+ if (ret)
+ return ret;
+ }
return ret;
}