Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.14 127/238] KVM: s390/mm: try a cow on read only pages for key ops | Date | Fri, 3 Oct 2014 14:30:42 -0700 |
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3.14-stable review patch. If anyone has any objections, please let me know.
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From: Christian Borntraeger <borntraeger@de.ibm.com>
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@de.ibm.com> Reviewed-by: Dominik Dingel <dingel@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/s390/mm/pgtable.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
--- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -810,11 +810,21 @@ 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 |
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