This is a note to let you know that I've just added the patch titled
KVM: s390/mm: try a cow on read only pages for key ops
to the 3.16-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-s390-mm-try-a-cow-on-read-only-pages-for-key-ops.patch
and it can be found in the queue-3.16 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ab3f285f227fec62868037e9b1b1fd18294a83b8 Mon Sep 17 00:00:00 2001
From: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Date: Tue, 19 Aug 2014 16:19:35 +0200
Subject: KVM: s390/mm: try a cow on read only pages for key ops
From: Christian Borntraeger <borntraeger@xxxxxxxxxx>
commit ab3f285f227fec62868037e9b1b1fd18294a83b8 upstream.
The PFMF instruction handler blindly wrote the storage key even if
the page was mapped R/O in the host. Lets try a COW before continuing
and bail out in case of errors.
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Reviewed-by: Dominik Dingel <dingel@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/mm/pgtable.c | 10 ++++++++++
1 file changed, 10 insertions(+)
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -986,11 +986,21 @@ int set_guest_storage_key(struct mm_stru
pte_t *ptep;
down_read(&mm->mmap_sem);
+retry:
ptep = get_locked_pte(current->mm, addr, &ptl);
if (unlikely(!ptep)) {
up_read(&mm->mmap_sem);
return -EFAULT;
}
+ if (!(pte_val(*ptep) & _PAGE_INVALID) &&
+ (pte_val(*ptep) & _PAGE_PROTECT)) {
+ pte_unmap_unlock(*ptep, ptl);
+ if (fixup_user_fault(current, mm, addr, FAULT_FLAG_WRITE)) {
+ up_read(&mm->mmap_sem);
+ return -EFAULT;
+ }
+ goto retry;
+ }
new = old = pgste_get_lock(ptep);
pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT |
Patches currently in stable-queue which might be from borntraeger@xxxxxxxxxx are
queue-3.16/kvm-s390-fix-user-triggerable-bug-in-dead-code.patch
queue-3.16/kvm-s390-mm-try-a-cow-on-read-only-pages-for-key-ops.patch
queue-3.16/kvm-s390-mm-fix-storage-key-corruption-during-swapping.patch
queue-3.16/kvm-s390-mm-fix-guest-storage-key-corruption-in-ptep_set_access_flags.patch
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