summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--arch/x86/include/asm/xen/page.h5
-rw-r--r--arch/x86/xen/p2m.c10
-rw-r--r--drivers/xen/grant-table.c31
3 files changed, 31 insertions, 15 deletions
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index c61934fbf22a..64a619d47d34 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -47,8 +47,9 @@ extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
extern unsigned long set_phys_range_identity(unsigned long pfn_s,
unsigned long pfn_e);
-extern int m2p_add_override(unsigned long mfn, struct page *page);
-extern int m2p_remove_override(struct page *page);
+extern int m2p_add_override(unsigned long mfn, struct page *page,
+ bool clear_pte);
+extern int m2p_remove_override(struct page *page, bool clear_pte);
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 141eb0de8b06..2d2b32af3a1d 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -650,7 +650,7 @@ static unsigned long mfn_hash(unsigned long mfn)
}
/* Add an MFN override for a particular page */
-int m2p_add_override(unsigned long mfn, struct page *page)
+int m2p_add_override(unsigned long mfn, struct page *page, bool clear_pte)
{
unsigned long flags;
unsigned long pfn;
@@ -662,7 +662,6 @@ int m2p_add_override(unsigned long mfn, struct page *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;
@@ -674,10 +673,9 @@ int m2p_add_override(unsigned long mfn, struct page *page)
if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn))))
return -ENOMEM;
- if (!PageHighMem(page))
+ if (clear_pte && !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);
@@ -685,7 +683,7 @@ int m2p_add_override(unsigned long mfn, struct page *page)
return 0;
}
-int m2p_remove_override(struct page *page)
+int m2p_remove_override(struct page *page, bool clear_pte)
{
unsigned long flags;
unsigned long mfn;
@@ -713,7 +711,7 @@ int m2p_remove_override(struct page *page)
spin_unlock_irqrestore(&m2p_override_lock, flags);
set_phys_to_machine(pfn, page->index);
- if (!PageHighMem(page))
+ if (clear_pte && !PageHighMem(page))
set_pte_at(&init_mm, address, ptep,
pfn_pte(pfn, PAGE_KERNEL));
/* No tlb flush necessary because the caller already
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 3745a318defc..fd725cde6ad1 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -466,13 +466,30 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
if (map_ops[i].status)
continue;
- /* m2p override only supported for GNTMAP_contains_pte mappings */
- if (!(map_ops[i].flags & GNTMAP_contains_pte))
- continue;
- pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
+ if (map_ops[i].flags & GNTMAP_contains_pte) {
+ pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
(map_ops[i].host_addr & ~PAGE_MASK));
- mfn = pte_mfn(*pte);
- ret = m2p_add_override(mfn, pages[i]);
+ mfn = pte_mfn(*pte);
+ } else {
+ /* If you really wanted to do this:
+ * mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
+ *
+ * The reason we do not implement it is b/c on the
+ * unmap path (gnttab_unmap_refs) we have no means of
+ * checking whether the page is !GNTMAP_contains_pte.
+ *
+ * That is without some extra data-structure to carry
+ * the struct page, bool clear_pte, and list_head next
+ * tuples and deal with allocation/delallocation, etc.
+ *
+ * The users of this API set the GNTMAP_contains_pte
+ * flag so lets just return not supported until it
+ * becomes neccessary to implement.
+ */
+ return -EOPNOTSUPP;
+ }
+ ret = m2p_add_override(mfn, pages[i],
+ map_ops[i].flags & GNTMAP_contains_pte);
if (ret)
return ret;
}
@@ -494,7 +511,7 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
return ret;
for (i = 0; i < count; i++) {
- ret = m2p_remove_override(pages[i]);
+ ret = m2p_remove_override(pages[i], true /* clear the PTE */);
if (ret)
return ret;
}