releases/4.4.44/kvm-x86-add-align16-instruction-flag.patch

   1 From d3fe959f81024072068e9ed86b39c2acfd7462a9 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar@redhat.com>
   3 Date: Tue, 8 Nov 2016 20:54:16 +0100
   4 Subject: KVM: x86: add Align16 instruction flag
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 From: Radim Krčmář <rkrcmar@redhat.com>
  10
  11 commit d3fe959f81024072068e9ed86b39c2acfd7462a9 upstream.
  12
  13 Needed for FXSAVE and FXRSTOR.
  14
  15 Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
  16 Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
  17 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  18
  19 ---
  20  arch/x86/kvm/emulate.c |   20 ++++++++++++--------
  21  1 file changed, 12 insertions(+), 8 deletions(-)
  22
  23 --- a/arch/x86/kvm/emulate.c
  24 +++ b/arch/x86/kvm/emulate.c
  25 @@ -172,6 +172,7 @@
  26  #define NearBranch  ((u64)1 << 52)  /* Near branches */
  27  #define No16       ((u64)1 << 53)  /* No 16 bit operand */
  28  #define IncSP       ((u64)1 << 54)  /* SP is incremented before ModRM calc */
  29 +#define Aligned16   ((u64)1 << 55)  /* Aligned to 16 byte boundary (e.g. FXSAVE) */
  30
  31  #define DstXacc     (DstAccLo | SrcAccHi | SrcWrite)
  32
  33 @@ -620,21 +621,24 @@ static void set_segment_selector(struct
  34   * depending on whether they're AVX encoded or not.
  35   *
  36   * Also included is CMPXCHG16B which is not a vector instruction, yet it is
  37 - * subject to the same check.
  38 + * subject to the same check.  FXSAVE and FXRSTOR are checked here too as their
  39 + * 512 bytes of data must be aligned to a 16 byte boundary.
  40   */
  41 -static bool insn_aligned(struct x86_emulate_ctxt *ctxt, unsigned size)
  42 +static unsigned insn_alignment(struct x86_emulate_ctxt *ctxt, unsigned size)
  43  {
  44         if (likely(size < 16))
  45 -               return false;
  46 +               return 1;
  47
  48         if (ctxt->d & Aligned)
  49 -               return true;
  50 +               return size;
  51         else if (ctxt->d & Unaligned)
  52 -               return false;
  53 +               return 1;
  54         else if (ctxt->d & Avx)
  55 -               return false;
  56 +               return 1;
  57 +       else if (ctxt->d & Aligned16)
  58 +               return 16;
  59         else
  60 -               return true;
  61 +               return size;
  62  }
  63
  64  static __always_inline int __linearize(struct x86_emulate_ctxt *ctxt,
  65 @@ -692,7 +696,7 @@ static __always_inline int __linearize(s
  66                 }
  67                 break;
  68         }
  69 -       if (insn_aligned(ctxt, size) && ((la & (size - 1)) != 0))
  70 +       if (la & (insn_alignment(ctxt, size) - 1))
  71                 return emulate_gp(ctxt, 0);
  72         return X86EMUL_CONTINUE;
  73  bad: