[PATCHv3 04/17] mm/page_alloc: Handle allocation for encrypted memory

Kirill A. Shutemov
2018-06-12T14:39:33Z

For encrypted memory, we need to allocated pages for a specific
encryption KeyID.

There are two cases when we need to allocate a page for encryption:

- Allocation for an encrypted VMA;

- Allocation for migration of encrypted page;

The first case can be covered within alloc_page_vma().

The second case requires few new page allocation routines that would
allocate the page for a specific KeyID.

Encrypted page has to be cleared after KeyID set. This is handled by
prep_encrypted_page() that will be provided by arch-specific code.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
arch/alpha/include/asm/page.h | 2 +-
include/linux/gfp.h | 38 ++++++++++++++++-----
include/linux/migrate.h | 8 +++--
mm/compaction.c | 4 +++
mm/mempolicy.c | 25 ++++++++++----
mm/migrate.c | 4 +--
mm/page_alloc.c | 63 +++++++++++++++++++++++++++++++++++
7 files changed, 122 insertions(+), 22 deletions(-)

diff --git a/arch/alpha/include/asm/page.h b/arch/alpha/include/asm/page.h
index f3fb2848470a..9a6fbb5269f3 100644
--- a/arch/alpha/include/asm/page.h
+++ b/arch/alpha/include/asm/page.h
@@ -18,7 +18,7 @@ extern void clear_page(void *page);
#define clear_user_page(page, vaddr, pg) clear_page(page)

#define __alloc_zeroed_user_highpage(movableflags, vma, vaddr) \
- alloc_page_vma(GFP_HIGHUSER | __GFP_ZERO | movableflags, vma, vmaddr)
+ alloc_page_vma(GFP_HIGHUSER | __GFP_ZERO | movableflags, vma, vaddr)
#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE

extern void copy_page(void * _to, void * _from);
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index fc5ab85278d5..59d607d135e9 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -446,16 +446,30 @@ static inline void arch_free_page(struct page *page, int order) { }
static inline void arch_alloc_page(struct page *page, int order) { }
#endif

+#ifndef prep_encrypted_page
+static inline void prep_encrypted_page(struct page *page, int order,
+ int keyid, bool zero)
+{
+}
+#endif
+
struct page *
__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
nodemask_t *nodemask);

+struct page *
+__alloc_pages_nodemask_keyid(gfp_t gfp_mask, unsigned int order,
+ int preferred_nid, nodemask_t *nodemask, int keyid);
+
static inline struct page *
__alloc_pages(gfp_t gfp_mask, unsigned int order, int preferred_nid)
{
return __alloc_pages_nodemask(gfp_mask, order, preferred_nid, NULL);
}

+struct page *__alloc_pages_node_keyid(int nid, int keyid,
+ gfp_t gfp_mask, unsigned int order);
+
/*
* Allocate pages, preferring the node given as nid. The node must be valid and
* online. For more general interface, see alloc_pages_node().
@@ -483,6 +497,19 @@ static inline struct page *alloc_pages_node(int nid, gfp_t gfp_mask,
return __alloc_pages_node(nid, gfp_mask, order);
}

+static inline struct page *alloc_pages_node_keyid(int nid, int keyid,
+ gfp_t gfp_mask, unsigned int order)
+{
+ if (nid == NUMA_NO_NODE)
+ nid = numa_mem_id();
+
+ return __alloc_pages_node_keyid(nid, keyid, gfp_mask, order);
+}
+
+extern struct page *alloc_pages_vma(gfp_t gfp_mask, int order,
+ struct vm_area_struct *vma, unsigned long addr,
+ int node, bool hugepage);
+
#ifdef CONFIG_NUMA
extern struct page *alloc_pages_current(gfp_t gfp_mask, unsigned order);

@@ -491,24 +518,17 @@ alloc_pages(gfp_t gfp_mask, unsigned int order)
{
return alloc_pages_current(gfp_mask, order);
}
-extern struct page *alloc_pages_vma(gfp_t gfp_mask, int order,
- struct vm_area_struct *vma, unsigned long addr,
- int node, bool hugepage);
-#define alloc_hugepage_vma(gfp_mask, vma, addr, order) \
- alloc_pages_vma(gfp_mask, order, vma, addr, numa_node_id(), true)
#else
#define alloc_pages(gfp_mask, order) \
alloc_pages_node(numa_node_id(), gfp_mask, order)
-#define alloc_pages_vma(gfp_mask, order, vma, addr, node, false)\
- alloc_pages(gfp_mask, order)
-#define alloc_hugepage_vma(gfp_mask, vma, addr, order) \
- alloc_pages(gfp_mask, order)
#endif
#define alloc_page(gfp_mask) alloc_pages(gfp_mask, 0)
#define alloc_page_vma(gfp_mask, vma, addr) \
alloc_pages_vma(gfp_mask, 0, vma, addr, numa_node_id(), false)
#define alloc_page_vma_node(gfp_mask, vma, addr, node) \
alloc_pages_vma(gfp_mask, 0, vma, addr, node, false)
+#define alloc_hugepage_vma(gfp_mask, vma, addr, order) \
+ alloc_pages_vma(gfp_mask, order, vma, addr, numa_node_id(), true)

extern unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order);
extern unsigned long get_zeroed_page(gfp_t gfp_mask);
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index f2b4abbca55e..6da504bad841 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -38,9 +38,11 @@ static inline struct page *new_page_nodemask(struct page *page,
unsigned int order = 0;
struct page *new_page = NULL;

- if (PageHuge(page))
+ if (PageHuge(page)) {
+ WARN_ON(page_keyid(page));
return alloc_huge_page_nodemask(page_hstate(compound_head(page)),
preferred_nid, nodemask);
+ }

if (PageTransHuge(page)) {
gfp_mask |= GFP_TRANSHUGE;
@@ -50,8 +52,8 @@ static inline struct page *new_page_nodemask(struct page *page,
if (PageHighMem(page) || (zone_idx(page_zone(page)) == ZONE_MOVABLE))
gfp_mask |= __GFP_HIGHMEM;

- new_page = __alloc_pages_nodemask(gfp_mask, order,
- preferred_nid, nodemask);
+ new_page = __alloc_pages_nodemask_keyid(gfp_mask, order,
+ preferred_nid, nodemask, page_keyid(page));

if (new_page && PageTransHuge(new_page))
prep_transhuge_page(new_page);
diff --git a/mm/compaction.c b/mm/compaction.c
index 29bd1df18b98..55261e634c34 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1170,6 +1170,7 @@ static struct page *compaction_alloc(struct page *migratepage,
{
struct compact_control *cc = (struct compact_control *)data;
struct page *freepage;
+ int keyid;

/*
* Isolate free pages if necessary, and if we are not aborting due to
@@ -1187,6 +1188,9 @@ static struct page *compaction_alloc(struct page *migratepage,
list_del(&freepage->lru);
cc->nr_freepages--;

+ keyid = page_keyid(migratepage);
+ if (keyid)
+ prep_encrypted_page(freepage, 0, keyid, false);
return freepage;
}

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 9ac49ef17b4e..00bccbececea 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -920,22 +920,24 @@ static void migrate_page_add(struct page *page, struct list_head *pagelist,
/* page allocation callback for NUMA node migration */
struct page *alloc_new_node_page(struct page *page, unsigned long node)
{
- if (PageHuge(page))
+ if (PageHuge(page)) {
+ WARN_ON(page_keyid(page));
return alloc_huge_page_node(page_hstate(compound_head(page)),
node);
- else if (PageTransHuge(page)) {
+ } else if (PageTransHuge(page)) {
struct page *thp;

- thp = alloc_pages_node(node,
+ thp = alloc_pages_node_keyid(node, page_keyid(page),
(GFP_TRANSHUGE | __GFP_THISNODE),
HPAGE_PMD_ORDER);
if (!thp)
return NULL;
prep_transhuge_page(thp);
return thp;
- } else
- return __alloc_pages_node(node, GFP_HIGHUSER_MOVABLE |
- __GFP_THISNODE, 0);
+ } else {
+ return __alloc_pages_node_keyid(node, page_keyid(page),
+ GFP_HIGHUSER_MOVABLE | __GFP_THISNODE, 0);
+ }
}

/*
@@ -2012,9 +2014,16 @@ alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
{
struct mempolicy *pol;
struct page *page;
- int preferred_nid;
+ bool zero = false;
+ int keyid, preferred_nid;
nodemask_t *nmask;

+ keyid = vma_keyid(vma);
+ if (keyid && gfp & __GFP_ZERO) {
+ zero = true;
+ gfp &= ~__GFP_ZERO;
+ }
+
pol = get_vma_policy(vma, addr);

if (pol->mode == MPOL_INTERLEAVE) {
@@ -2057,6 +2066,8 @@ alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
page = __alloc_pages_nodemask(gfp, order, preferred_nid, nmask);
mpol_cond_put(pol);
out:
+ if (page && keyid)
+ prep_encrypted_page(page, order, keyid, zero);
return page;
}

diff --git a/mm/migrate.c b/mm/migrate.c
index 8c0af0f7cab1..eb8dea219dcb 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1847,7 +1847,7 @@ static struct page *alloc_misplaced_dst_page(struct page *page,
int nid = (int) data;
struct page *newpage;

- newpage = __alloc_pages_node(nid,
+ newpage = __alloc_pages_node_keyid(nid, page_keyid(page),
(GFP_HIGHUSER_MOVABLE |
__GFP_THISNODE | __GFP_NOMEMALLOC |
__GFP_NORETRY | __GFP_NOWARN) &
@@ -2030,7 +2030,7 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
if (numamigrate_update_ratelimit(pgdat, HPAGE_PMD_NR))
goto out_dropref;

- new_page = alloc_pages_node(node,
+ new_page = alloc_pages_node_keyid(node, page_keyid(page),
(GFP_TRANSHUGE_LIGHT | __GFP_THISNODE),
HPAGE_PMD_ORDER);
if (!new_page)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 22320ea27489..472286b0553f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3700,6 +3700,49 @@ should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_fla
}
#endif /* CONFIG_COMPACTION */

+#ifndef CONFIG_NUMA
+struct page *alloc_pages_vma(gfp_t gfp_mask, int order,
+ struct vm_area_struct *vma, unsigned long addr,
+ int node, bool hugepage)
+{
+ struct page *page;
+ bool zero = false;
+ int keyid = vma_keyid(vma);
+
+ if (keyid && (gfp_mask & __GFP_ZERO)) {
+ zero = true;
+ gfp_mask &= ~__GFP_ZERO;
+ }
+
+ page = alloc_pages(gfp_mask, order);
+ if (page && keyid)
+ prep_encrypted_page(page, order, keyid, zero);
+
+ return page;
+}
+#endif
+
+struct page * __alloc_pages_node_keyid(int nid, int keyid,
+ gfp_t gfp_mask, unsigned int order)
+{
+ struct page *page;
+ bool zero = false;
+
+ VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES);
+ VM_WARN_ON(!node_online(nid));
+
+ if (keyid && (gfp_mask & __GFP_ZERO)) {
+ zero = true;
+ gfp_mask &= ~__GFP_ZERO;
+ }
+
+ page = __alloc_pages(gfp_mask, order, nid);
+ if (page && keyid)
+ prep_encrypted_page(page, order, keyid, zero);
+
+ return page;
+}
+
#ifdef CONFIG_LOCKDEP
struct lockdep_map __fs_reclaim_map =
STATIC_LOCKDEP_MAP_INIT("fs_reclaim", &__fs_reclaim_map);
@@ -4396,6 +4439,26 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
}
EXPORT_SYMBOL(__alloc_pages_nodemask);

+struct page *
+__alloc_pages_nodemask_keyid(gfp_t gfp_mask, unsigned int order,
+ int preferred_nid, nodemask_t *nodemask, int keyid)
+{
+ struct page *page;
+ bool zero = false;
+
+ if (keyid && (gfp_mask & __GFP_ZERO)) {
+ zero = true;
+ gfp_mask &= ~__GFP_ZERO;
+ }
+
+ page = __alloc_pages_nodemask(gfp_mask, order,
+ preferred_nid, nodemask);
+ if (page && keyid)
+ prep_encrypted_page(page, order, keyid, zero);
+ return page;
+}
+EXPORT_SYMBOL(__alloc_pages_nodemask_keyid);
+
/*
* Common helper functions.
*/
--
2.17.1