From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f70.google.com (mail-pl0-f70.google.com [209.85.160.70]) by kanga.kvack.org (Postfix) with ESMTP id A38016B0006 for ; Tue, 17 Jul 2018 07:21:46 -0400 (EDT) Received: by mail-pl0-f70.google.com with SMTP id 39-v6so459247ple.6 for ; Tue, 17 Jul 2018 04:21:46 -0700 (PDT) Received: from mga17.intel.com (mga17.intel.com. [192.55.52.151]) by mx.google.com with ESMTPS id f62-v6si697286pfg.165.2018.07.17.04.21.45 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 17 Jul 2018 04:21:45 -0700 (PDT) From: "Kirill A. Shutemov" Subject: [PATCHv5 02/19] mm: Do not use zero page in encrypted pages Date: Tue, 17 Jul 2018 14:20:12 +0300 Message-Id: <20180717112029.42378-3-kirill.shutemov@linux.intel.com> In-Reply-To: <20180717112029.42378-1-kirill.shutemov@linux.intel.com> References: <20180717112029.42378-1-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Ingo Molnar , x86@kernel.org, Thomas Gleixner , "H. Peter Anvin" , Tom Lendacky Cc: Dave Hansen , Kai Huang , Jacob Pan , linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Kirill A. Shutemov" Zero page is not encrypted and putting it into encrypted VMA produces garbage. We can map zero page with KeyID-0 into an encrypted VMA, but this would be violation security boundary between encryption domains. Forbid zero pages in encrypted VMAs. Signed-off-by: Kirill A. Shutemov --- arch/s390/include/asm/pgtable.h | 2 +- include/linux/mm.h | 4 ++-- mm/huge_memory.c | 3 +-- mm/memory.c | 3 +-- 4 files changed, 5 insertions(+), 7 deletions(-) diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 5ab636089c60..2e8658962aae 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -505,7 +505,7 @@ static inline int mm_alloc_pgste(struct mm_struct *mm) * In the case that a guest uses storage keys * faults should no longer be backed by zero pages */ -#define mm_forbids_zeropage mm_has_pgste +#define vma_forbids_zeropage(vma) mm_has_pgste(vma->vm_mm) static inline int mm_uses_skeys(struct mm_struct *mm) { #ifdef CONFIG_PGSTE diff --git a/include/linux/mm.h b/include/linux/mm.h index c8780c5835ad..151d6e6b16e5 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -92,8 +92,8 @@ extern int mmap_rnd_compat_bits __read_mostly; * s390 does this to prevent multiplexing of hardware bits * related to the physical page in case of virtualization. */ -#ifndef mm_forbids_zeropage -#define mm_forbids_zeropage(X) (0) +#ifndef vma_forbids_zeropage +#define vma_forbids_zeropage(vma) vma_keyid(vma) #endif /* diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 1cd7c1a57a14..83f096c7299b 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -676,8 +676,7 @@ int do_huge_pmd_anonymous_page(struct vm_fault *vmf) return VM_FAULT_OOM; if (unlikely(khugepaged_enter(vma, vma->vm_flags))) return VM_FAULT_OOM; - if (!(vmf->flags & FAULT_FLAG_WRITE) && - !mm_forbids_zeropage(vma->vm_mm) && + if (!(vmf->flags & FAULT_FLAG_WRITE) && !vma_forbids_zeropage(vma) && transparent_hugepage_use_zero_page()) { pgtable_t pgtable; struct page *zero_page; diff --git a/mm/memory.c b/mm/memory.c index 02fbef2bd024..a705637d2ded 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3139,8 +3139,7 @@ static int do_anonymous_page(struct vm_fault *vmf) return 0; /* Use the zero-page for reads */ - if (!(vmf->flags & FAULT_FLAG_WRITE) && - !mm_forbids_zeropage(vma->vm_mm)) { + if (!(vmf->flags & FAULT_FLAG_WRITE) && !vma_forbids_zeropage(vma)) { entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address), vma->vm_page_prot)); vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, -- 2.18.0