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Subject[PATCH v2] mm: Track page table modifications in __apply_to_page_range()
Date
From: Joerg Roedel <jroedel@suse.de>

The __apply_to_page_range() function is also used to change and/or
allocate page-table pages in the vmalloc area of the address space.
Make sure these changes get synchronized to other page-tables in the
system by calling arch_sync_kernel_mappings() when necessary.

Tested-by: Chris Wilson <chris@chris-wilson.co.uk> #x86-32
Cc: <stable@vger.kernel.org> # v5.8+
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
mm/memory.c | 36 +++++++++++++++++++++++-------------
1 file changed, 23 insertions(+), 13 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 3a7779d9891d..1b7d846f6992 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -83,6 +83,7 @@
#include <asm/tlb.h>
#include <asm/tlbflush.h>

+#include "pgalloc-track.h"
#include "internal.h"

#if defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS) && !defined(CONFIG_COMPILE_TEST)
@@ -2206,7 +2207,8 @@ EXPORT_SYMBOL(vm_iomap_memory);

static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
unsigned long addr, unsigned long end,
- pte_fn_t fn, void *data, bool create)
+ pte_fn_t fn, void *data, bool create,
+ pgtbl_mod_mask *mask)
{
pte_t *pte;
int err = 0;
@@ -2214,7 +2216,7 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,

if (create) {
pte = (mm == &init_mm) ?
- pte_alloc_kernel(pmd, addr) :
+ pte_alloc_kernel_track(pmd, addr, mask) :
pte_alloc_map_lock(mm, pmd, addr, &ptl);
if (!pte)
return -ENOMEM;
@@ -2235,6 +2237,7 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
break;
}
} while (addr += PAGE_SIZE, addr != end);
+ *mask |= PGTBL_PTE_MODIFIED;

arch_leave_lazy_mmu_mode();

@@ -2245,7 +2248,8 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,

static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
unsigned long addr, unsigned long end,
- pte_fn_t fn, void *data, bool create)
+ pte_fn_t fn, void *data, bool create,
+ pgtbl_mod_mask *mask)
{
pmd_t *pmd;
unsigned long next;
@@ -2254,7 +2258,7 @@ static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
BUG_ON(pud_huge(*pud));

if (create) {
- pmd = pmd_alloc(mm, pud, addr);
+ pmd = pmd_alloc_track(mm, pud, addr, mask);
if (!pmd)
return -ENOMEM;
} else {
@@ -2264,7 +2268,7 @@ static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
next = pmd_addr_end(addr, end);
if (create || !pmd_none_or_clear_bad(pmd)) {
err = apply_to_pte_range(mm, pmd, addr, next, fn, data,
- create);
+ create, mask);
if (err)
break;
}
@@ -2274,14 +2278,15 @@ static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,

static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d,
unsigned long addr, unsigned long end,
- pte_fn_t fn, void *data, bool create)
+ pte_fn_t fn, void *data, bool create,
+ pgtbl_mod_mask *mask)
{
pud_t *pud;
unsigned long next;
int err = 0;

if (create) {
- pud = pud_alloc(mm, p4d, addr);
+ pud = pud_alloc_track(mm, p4d, addr, mask);
if (!pud)
return -ENOMEM;
} else {
@@ -2291,7 +2296,7 @@ static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d,
next = pud_addr_end(addr, end);
if (create || !pud_none_or_clear_bad(pud)) {
err = apply_to_pmd_range(mm, pud, addr, next, fn, data,
- create);
+ create, mask);
if (err)
break;
}
@@ -2301,14 +2306,15 @@ static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d,

static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd,
unsigned long addr, unsigned long end,
- pte_fn_t fn, void *data, bool create)
+ pte_fn_t fn, void *data, bool create,
+ pgtbl_mod_mask *mask)
{
p4d_t *p4d;
unsigned long next;
int err = 0;

if (create) {
- p4d = p4d_alloc(mm, pgd, addr);
+ p4d = p4d_alloc_track(mm, pgd, addr, mask);
if (!p4d)
return -ENOMEM;
} else {
@@ -2318,7 +2324,7 @@ static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd,
next = p4d_addr_end(addr, end);
if (create || !p4d_none_or_clear_bad(p4d)) {
err = apply_to_pud_range(mm, p4d, addr, next, fn, data,
- create);
+ create, mask);
if (err)
break;
}
@@ -2331,8 +2337,9 @@ static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr,
void *data, bool create)
{
pgd_t *pgd;
- unsigned long next;
+ unsigned long start = addr, next;
unsigned long end = addr + size;
+ pgtbl_mod_mask mask = 0;
int err = 0;

if (WARN_ON(addr >= end))
@@ -2343,11 +2350,14 @@ static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr,
next = pgd_addr_end(addr, end);
if (!create && pgd_none_or_clear_bad(pgd))
continue;
- err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create);
+ err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create, &mask);
if (err)
break;
} while (pgd++, addr = next, addr != end);

+ if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
+ arch_sync_kernel_mappings(start, start + size);
+
return err;
}

--
2.28.0
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