Displaying 20 results from an estimated 35 matches for "is_zero_pfn".
2020 Jul 31
1
[PATCH v4 6/6] mm/migrate: remove range invalidation in migrate_vma_pages()
...ration entry (so the page can't be faulted and the CPU page table set
> valid again), and there are no extra page references (pins), the page
> "should not be modified".
That is the physical page though, it doesn't prove nobody else is
reading the PTE.
> For pte_none()/is_zero_pfn() entries, migrate_vma_setup() leaves the
> pte_none()/is_zero_pfn() entry in place but does still call
> mmu_notifier_invalidate_range_start() for the whole range being migrated.
Ok..
> In the migrate_vma_pages() step, the pte page table is locked and the
> pte entry checked to be su...
2020 Jul 28
2
[PATCH v4 6/6] mm/migrate: remove range invalidation in migrate_vma_pages()
On Thu, Jul 23, 2020 at 03:30:04PM -0700, Ralph Campbell wrote:
> When migrating the special zero page, migrate_vma_pages() calls
> mmu_notifier_invalidate_range_start() before replacing the zero page
> PFN in the CPU page tables. This is unnecessary since the range was
> invalidated in migrate_vma_setup() and the page table entry is checked
> to be sure it hasn't changed
2019 Sep 12
1
[PATCH 2/4] mm/hmm: allow snapshot of the special zero page
...> @@ -532,7 +532,7 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
> return -EBUSY;
> } else if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && pte_special(pte)) {
> *pfn = range->values[HMM_PFN_SPECIAL];
> - return -EFAULT;
> + return is_zero_pfn(pte_pfn(pte)) ? 0 : -EFAULT;
Any chance to just use a normal if here:
if (!is_zero_pfn(pte_pfn(pte)))
return -EFAULT;
return 0;
2020 Jul 28
0
[PATCH v4 6/6] mm/migrate: remove range invalidation in migrate_vma_pages()
...p() stage,
and the page is isolated from the LRU cache, locked, unmapped, and the page table
holds a migration entry (so the page can't be faulted and the CPU page table set
valid again), and there are no extra page references (pins), the page
"should not be modified".
For pte_none()/is_zero_pfn() entries, migrate_vma_setup() leaves the
pte_none()/is_zero_pfn() entry in place but does still call
mmu_notifier_invalidate_range_start() for the whole range being migrated.
In the migrate_vma_pages() step, the pte page table is locked and the
pte entry checked to be sure it is still pte_none/is...
2019 Jul 29
1
[PATCH 9/9] mm: remove the MIGRATE_PFN_WRITE flag
...@ -2240,7 +2241,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
> mpfn = migrate_pfn(page_to_pfn(page)) |
> MIGRATE_PFN_MIGRATE;
> if (is_write_device_private_entry(entry))
> - mpfn |= MIGRATE_PFN_WRITE;
> + writable = true;
> } else {
> if (is_zero_pfn(pfn)) {
> mpfn = MIGRATE_PFN_MIGRATE;
> @@ -2250,7 +2251,8 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
> }
> page = vm_normal_page(migrate->vma, addr, pte);
> mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;
> - mpfn |= pte_write(pte) ? MIGRATE_PFN_W...
2019 Jun 26
0
[PATCH 04/25] mm: remove MEMORY_DEVICE_PUBLIC support
...om both the device and
- the CPU
-
config FRAME_VECTOR
bool
diff --git a/mm/gup.c b/mm/gup.c
index ddde097cf9e4..fe131d879c70 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -605,13 +605,6 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address,
if ((gup_flags & FOLL_DUMP) || !is_zero_pfn(pte_pfn(*pte)))
goto unmap;
*page = pte_page(*pte);
-
- /*
- * This should never happen (a device public page in the gate
- * area).
- */
- if (is_device_public_page(*page))
- goto unmap;
}
if (unlikely(!try_get_page(*page))) {
ret = -ENOMEM;
diff --git a/mm/hmm.c b/mm/hmm.c...
2019 Jul 29
0
[PATCH 9/9] mm: remove the MIGRATE_PFN_WRITE flag
...false;
pte_t pte;
pte = *ptep;
@@ -2240,7 +2241,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
mpfn = migrate_pfn(page_to_pfn(page)) |
MIGRATE_PFN_MIGRATE;
if (is_write_device_private_entry(entry))
- mpfn |= MIGRATE_PFN_WRITE;
+ writable = true;
} else {
if (is_zero_pfn(pfn)) {
mpfn = MIGRATE_PFN_MIGRATE;
@@ -2250,7 +2251,8 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
}
page = vm_normal_page(migrate->vma, addr, pte);
mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;
- mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0;
+ if (pte_write(pte))...
2019 Sep 11
0
[PATCH 2/4] mm/hmm: allow snapshot of the special zero page
...--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -532,7 +532,7 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
return -EBUSY;
} else if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && pte_special(pte)) {
*pfn = range->values[HMM_PFN_SPECIAL];
- return -EFAULT;
+ return is_zero_pfn(pte_pfn(pte)) ? 0 : -EFAULT;
}
*pfn = hmm_device_entry_from_pfn(range, pte_pfn(pte)) | cpu_flags;
--
2.20.1
2020 Jun 19
0
[PATCH 01/16] mm: fix migrate_vma_setup() src_owner and normal pages
...8..24535281cea3 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2295,8 +2295,6 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
if (is_write_device_private_entry(entry))
mpfn |= MIGRATE_PFN_WRITE;
} else {
- if (migrate->src_owner)
- goto next;
pfn = pte_pfn(pte);
if (is_zero_pfn(pfn)) {
mpfn = MIGRATE_PFN_MIGRATE;
--
2.20.1
2020 Mar 16
0
[PATCH 2/4] mm: handle multiple owners of device private pages in migrate_vma
...pgmap->owner != migrate->src_owner)
+ goto next;
+
mpfn = migrate_pfn(page_to_pfn(page)) |
MIGRATE_PFN_MIGRATE;
if (is_write_device_private_entry(entry))
mpfn |= MIGRATE_PFN_WRITE;
} else {
+ if (migrate->src_owner)
+ goto next;
pfn = pte_pfn(pte);
if (is_zero_pfn(pfn)) {
mpfn = MIGRATE_PFN_MIGRATE;
--
2.24.1
2020 Jul 06
0
[PATCH 2/5] mm/migrate: add a direction parameter to migrate_vma
...page)) |
@@ -2295,7 +2296,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
if (is_write_device_private_entry(entry))
mpfn |= MIGRATE_PFN_WRITE;
} else {
- if (migrate->src_owner)
+ if (migrate->dir != MIGRATE_VMA_FROM_SYSTEM)
goto next;
pfn = pte_pfn(pte);
if (is_zero_pfn(pfn)) {
--
2.20.1
2020 Jul 13
0
[PATCH v2 2/5] mm/migrate: add a direction parameter to migrate_vma
...page)) |
@@ -2295,7 +2296,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
if (is_write_device_private_entry(entry))
mpfn |= MIGRATE_PFN_WRITE;
} else {
- if (migrate->src_owner)
+ if (migrate->dir != MIGRATE_VMA_FROM_SYSTEM)
goto next;
pfn = pte_pfn(pte);
if (is_zero_pfn(pfn)) {
--
2.20.1
2019 Jul 29
2
[PATCH 9/9] mm: remove the MIGRATE_PFN_WRITE flag
...gt; @@ -2240,7 +2241,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
> mpfn = migrate_pfn(page_to_pfn(page)) |
> MIGRATE_PFN_MIGRATE;
> if (is_write_device_private_entry(entry))
> - mpfn |= MIGRATE_PFN_WRITE;
> + writable = true;
> } else {
> if (is_zero_pfn(pfn)) {
> mpfn = MIGRATE_PFN_MIGRATE;
> @@ -2250,7 +2251,8 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
> }
> page = vm_normal_page(migrate->vma, addr, pte);
> mpfn = migrate_pfn(pfn) | MIGRATE_PFN_MIGRATE;
> - mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE...
2020 Jul 21
0
[PATCH v3 2/5] mm/migrate: add a flags parameter to migrate_vma
...@ -2295,7 +2297,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
if (is_write_device_private_entry(entry))
mpfn |= MIGRATE_PFN_WRITE;
} else {
- if (migrate->src_owner)
+ if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
goto next;
pfn = pte_pfn(pte);
if (is_zero_pfn(pfn)) {
--
2.20.1
2020 Jul 23
0
[PATCH v4 2/6] mm/migrate: add a flags parameter to migrate_vma
...@ -2295,7 +2297,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
if (is_write_device_private_entry(entry))
mpfn |= MIGRATE_PFN_WRITE;
} else {
- if (migrate->src_owner)
+ if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM))
goto next;
pfn = pte_pfn(pte);
if (is_zero_pfn(pfn)) {
--
2.20.1
2016 Oct 26
2
CVE-2016-5195 DirtyCOW : Critical Linux Kernel Flaw
...RITE) && !pte_write(pte))
- goto unlock;
-
page = vm_normal_page(vma, address, pte);
+ if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, page, flags)) {
+ pte_unmap_unlock(ptep, ptl);
+ return NULL;
+ }
if (unlikely(!page)) {
if ((flags & FOLL_DUMP) ||
!is_zero_pfn(pte_pfn(pte)))
@@ -1290,7 +1309,6 @@ split_fallthrough:
*/
mark_page_accessed(page);
}
-unlock:
pte_unmap_unlock(ptep, ptl);
out:
return page;
@@ -1489,17 +1507,13 @@ int __get_user_pages(struct task_struct
* The VM_FAULT_WRITE bit tells us that
* do_wp_page has broken CO...
2016 Oct 25
5
CVE-2016-5195 DirtyCOW : Critical Linux Kernel Flaw
On Tue, 25 Oct 2016 10:06:12 +0200
Christian Anthon <anthon at rth.dk> wrote:
> What is the best approach on centos 6 to mitigate the problem is
> officially patched? As far as I can tell Centos 6 is vulnerable to
> attacks using ptrace.
I can confirm that c6 is vulnerable, we're running a patched kernel
(local build) using a rhel6 adaptation of the upstream fix.
Ask
2020 Mar 16
14
ensure device private pages have an owner v2
When acting on device private mappings a driver needs to know if the
device (or other entity in case of kvmppc) actually owns this private
mapping. This series adds an owner field and converts the migrate_vma
code over to check it. I looked into doing the same for
hmm_range_fault, but as far as I can tell that code has never been
wired up to actually work for device private memory, so instead of
2020 Jul 06
8
[PATCH 0/5] mm/migrate: avoid device private invalidations
The goal for this series is to avoid device private memory TLB
invalidations when migrating a range of addresses from system
memory to device private memory and some of those pages have already
been migrated. The approach taken is to introduce a new mmu notifier
invalidation event type and use that in the device driver to skip
invalidation callbacks from migrate_vma_setup(). The device driver is
2019 Sep 11
6
[PATCH 0/4] HMM tests and minor fixes
These changes are based on Jason's latest hmm branch.
Patch 1 was previously posted here [1] but was dropped from the orginal
series. Hopefully, the tests will reduce concerns about edge conditions.
I'm sure more tests could be usefully added but I thought this was a good
starting point.
[1] https://lore.kernel.org/linux-mm/20190726005650.2566-6-rcampbell at nvidia.com/
Ralph Campbell