diff mbox

[PATCHv3,01/17] mm: Do no merge VMAs with different encryption KeyIDs

Message ID 20180612143915.68065-2-kirill.shutemov@linux.intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Kirill A. Shutemov June 12, 2018, 2:38 p.m. UTC
VMAs with different KeyID do not mix together. Only VMAs with the same
KeyID are compatible.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/mm.h | 7 +++++++
 mm/mmap.c          | 3 ++-
 2 files changed, 9 insertions(+), 1 deletion(-)

Comments

Dave Hansen June 13, 2018, 5:45 p.m. UTC | #1
On 06/12/2018 07:38 AM, Kirill A. Shutemov wrote:
> VMAs with different KeyID do not mix together. Only VMAs with the same
> KeyID are compatible.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
>  include/linux/mm.h | 7 +++++++
>  mm/mmap.c          | 3 ++-
>  2 files changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 02a616e2f17d..1c3c15f37ed6 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1492,6 +1492,13 @@ static inline bool vma_is_anonymous(struct vm_area_struct *vma)
>  	return !vma->vm_ops;
>  }
>  
> +#ifndef vma_keyid
> +static inline int vma_keyid(struct vm_area_struct *vma)
> +{
> +	return 0;
> +}
> +#endif

I'm generally not a fan of this #ifdef'ing method.  It makes it hard to
figure out who is supposed to define it, and it's also substantially
more fragile in the face of #include ordering.

I'd much rather see some Kconfig involvement, like
CONFIG_ARCH_HAS_MEM_ENCRYPTION or something.
Kirill A. Shutemov June 13, 2018, 8:13 p.m. UTC | #2
On Wed, Jun 13, 2018 at 05:45:24PM +0000, Dave Hansen wrote:
> On 06/12/2018 07:38 AM, Kirill A. Shutemov wrote:
> > VMAs with different KeyID do not mix together. Only VMAs with the same
> > KeyID are compatible.
> > 
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > ---
> >  include/linux/mm.h | 7 +++++++
> >  mm/mmap.c          | 3 ++-
> >  2 files changed, 9 insertions(+), 1 deletion(-)
> > 
> > diff --git a/include/linux/mm.h b/include/linux/mm.h
> > index 02a616e2f17d..1c3c15f37ed6 100644
> > --- a/include/linux/mm.h
> > +++ b/include/linux/mm.h
> > @@ -1492,6 +1492,13 @@ static inline bool vma_is_anonymous(struct vm_area_struct *vma)
> >  	return !vma->vm_ops;
> >  }
> >  
> > +#ifndef vma_keyid
> > +static inline int vma_keyid(struct vm_area_struct *vma)
> > +{
> > +	return 0;
> > +}
> > +#endif
> 
> I'm generally not a fan of this #ifdef'ing method.  It makes it hard to
> figure out who is supposed to define it, and it's also substantially
> more fragile in the face of #include ordering.
> 
> I'd much rather see some Kconfig involvement, like
> CONFIG_ARCH_HAS_MEM_ENCRYPTION or something.

Well, it's matter of taste, I guess. I do prefer per-function #ifdef'ing.
It seems more flexible to me.

I can rework it if maintainers prefer to see config option instead.
diff mbox

Patch

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 02a616e2f17d..1c3c15f37ed6 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1492,6 +1492,13 @@  static inline bool vma_is_anonymous(struct vm_area_struct *vma)
 	return !vma->vm_ops;
 }
 
+#ifndef vma_keyid
+static inline int vma_keyid(struct vm_area_struct *vma)
+{
+	return 0;
+}
+#endif
+
 #ifdef CONFIG_SHMEM
 /*
  * The vma_is_shmem is not inline because it is used only by slow
diff --git a/mm/mmap.c b/mm/mmap.c
index d817764a9974..3ff89fc1752b 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1217,7 +1217,8 @@  static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *
 		mpol_equal(vma_policy(a), vma_policy(b)) &&
 		a->vm_file == b->vm_file &&
 		!((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC|VM_SOFTDIRTY)) &&
-		b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT);
+		b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT) &&
+		vma_keyid(a) == vma_keyid(b);
 }
 
 /*