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* [PATCH 1/4] mm: Export flush_vm_area() to sync the PTEs upon construction
@ 2020-08-21  8:50 ` Chris Wilson
  0 siblings, 0 replies; 40+ messages in thread
From: Chris Wilson @ 2020-08-21  8:50 UTC (permalink / raw)
  To: linux-kernel, intel-gfx
  Cc: linux-mm, Chris Wilson, Pavel Machek, Andrew Morton,
	Joerg Roedel, Linus Torvalds, Dave Airlie, Joonas Lahtinen,
	Rodrigo Vivi, David Vrabel, stable

The alloc_vm_area() is another method for drivers to
vmap/map_kernel_range that uses apply_to_page_range() rather than the
direct vmalloc walkers. This is missing the page table modification
tracking, and the ability to synchronize the PTE updates afterwards.
Provide flush_vm_area() for the users of alloc_vm_area() that assumes
the worst and ensures that the page directories are correctly flushed
upon construction.

The impact is most pronounced on x86_32 due to the delayed set_pmd().

Reported-by: Pavel Machek <pavel@ucw.cz>
References: 2ba3e6947aed ("mm/vmalloc: track which page-table levels were modified")
References: 86cf69f1d893 ("x86/mm/32: implement arch_sync_kernel_mappings()")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: <stable@vger.kernel.org> # v5.8+
---
 include/linux/vmalloc.h |  1 +
 mm/vmalloc.c            | 16 ++++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 0221f852a7e1..a253b27df0ac 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -204,6 +204,7 @@ static inline void set_vm_flush_reset_perms(void *addr)
 
 /* Allocate/destroy a 'vmalloc' VM area. */
 extern struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes);
+extern void flush_vm_area(struct vm_struct *area);
 extern void free_vm_area(struct vm_struct *area);
 
 /* for /dev/kmem */
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index b482d240f9a2..c41934486031 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3078,6 +3078,22 @@ struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
 }
 EXPORT_SYMBOL_GPL(alloc_vm_area);
 
+void flush_vm_area(struct vm_struct *area)
+{
+	unsigned long addr = (unsigned long)area->addr;
+
+	/* apply_to_page_range() doesn't track the damage, assume the worst */
+	if (ARCH_PAGE_TABLE_SYNC_MASK & (PGTBL_PTE_MODIFIED |
+					 PGTBL_PMD_MODIFIED |
+					 PGTBL_PUD_MODIFIED |
+					 PGTBL_P4D_MODIFIED |
+					 PGTBL_PGD_MODIFIED))
+		arch_sync_kernel_mappings(addr, addr + area->size);
+
+	flush_cache_vmap(addr, area->size);
+}
+EXPORT_SYMBOL_GPL(flush_vm_area);
+
 void free_vm_area(struct vm_struct *area)
 {
 	struct vm_struct *ret;
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 40+ messages in thread

end of thread, other threads:[~2020-08-21 13:02 UTC | newest]

Thread overview: 40+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-08-21  8:50 [PATCH 1/4] mm: Export flush_vm_area() to sync the PTEs upon construction Chris Wilson
2020-08-21  8:50 ` [Intel-gfx] " Chris Wilson
2020-08-21  8:50 ` [PATCH 2/4] drm/i915/gem: Sync the vmap " Chris Wilson
2020-08-21  8:50   ` [Intel-gfx] " Chris Wilson
2020-08-21 12:41   ` Linus Torvalds
2020-08-21 12:41     ` [Intel-gfx] " Linus Torvalds
2020-08-21 12:41     ` Linus Torvalds
2020-08-21 13:01     ` Chris Wilson
2020-08-21 13:01       ` [Intel-gfx] " Chris Wilson
2020-08-21  8:50 ` [PATCH 3/4] drm/i915/gem: Use set_pte_at() for assigning the vmapped PTE Chris Wilson
2020-08-21  8:50   ` [Intel-gfx] " Chris Wilson
2020-08-21  8:50 ` [PATCH 4/4] drm/i915/gem: Replace reloc chain with terminator on error unwind Chris Wilson
2020-08-21  8:50   ` [Intel-gfx] " Chris Wilson
2020-08-21  9:14 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with [1/4] mm: Export flush_vm_area() to sync the PTEs upon construction Patchwork
2020-08-21  9:16 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork
2020-08-21  9:29 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2020-08-21  9:51 ` [PATCH 1/4] " Joerg Roedel
2020-08-21  9:51   ` [Intel-gfx] " Joerg Roedel
2020-08-21  9:54   ` Chris Wilson
2020-08-21  9:54     ` [Intel-gfx] " Chris Wilson
2020-08-21 10:22     ` Joerg Roedel
2020-08-21 10:22       ` [Intel-gfx] " Joerg Roedel
2020-08-21 10:36       ` Chris Wilson
2020-08-21 10:36         ` [Intel-gfx] " Chris Wilson
2020-08-21 10:09 ` [PATCH] mm: Track page table modifications in __apply_to_page_range() construction Joerg Roedel
2020-08-21 10:09   ` [Intel-gfx] " Joerg Roedel
2020-08-21 10:13   ` Chris Wilson
2020-08-21 10:13     ` [Intel-gfx] " Chris Wilson
2020-08-21 10:23     ` Joerg Roedel
2020-08-21 10:23       ` [Intel-gfx] " Joerg Roedel
2020-08-21 10:39       ` Chris Wilson
2020-08-21 10:39         ` [Intel-gfx] " Chris Wilson
2020-08-21 11:38         ` Chris Wilson
2020-08-21 11:38           ` [Intel-gfx] " Chris Wilson
2020-08-21 12:18           ` Joerg Roedel
2020-08-21 12:18             ` [Intel-gfx] " Joerg Roedel
2020-08-21 10:53   ` Greg KH
2020-08-21 10:53     ` [Intel-gfx] " Greg KH
2020-08-21 10:27 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for series starting with mm: Track page table modifications in __apply_to_page_range() construction (rev2) Patchwork
2020-08-21 11:33 ` [Intel-gfx] ✓ Fi.CI.IGT: success for series starting with [1/4] mm: Export flush_vm_area() to sync the PTEs upon construction Patchwork

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