fix-register-corruption-in-pvclock-scale-delta.patch

   1 From: Zachary Amsden <zamsden@redhat.com>
   2 Date: Thu, 16 Jun 2011 03:50:04 +0000 (-0700)
   3 Subject: KVM: Fix register corruption in pvclock_scale_delta
   4 X-Git-Url: http://git.kernel.org/?p=virt%2Fkvm%2Fkvm.git;a=commitdiff_plain;h=eaa6a665a3c0fb5f8dbf25bca02eae5594095f4f
   5
   6 KVM: Fix register corruption in pvclock_scale_delta
   7
   8 The 128-bit multiply in pvclock.h was missing an output constraint for
   9 EDX which caused a register corruption to appear.  Thanks to Ulrich for
  10 diagnosing the EDX corruption and Avi for providing this fix.
  11
  12 Signed-off-by: Zachary Amsden <zamsden@redhat.com>
  13 Signed-off-by: Avi Kivity <avi@redhat.com>
  14 ---
  15
  16 diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h
  17 index 31d84ac..a518c0a 100644
  18 --- a/arch/x86/include/asm/pvclock.h
  19 +++ b/arch/x86/include/asm/pvclock.h
  20 @@ -22,6 +22,8 @@ static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
  21         u64 product;
  22  #ifdef __i386__
  23         u32 tmp1, tmp2;
  24 +#else
  25 +       ulong tmp;
  26  #endif
  27
  28         if (shift < 0)
  29 @@ -42,8 +44,11 @@ static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
  30                 : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
  31  #elif defined(__x86_64__)
  32         __asm__ (
  33 -               "mul %%rdx ; shrd $32,%%rdx,%%rax"
  34 -               : "=a" (product) : "0" (delta), "d" ((u64)mul_frac) );
  35 +               "mul %[mul_frac] ; shrd $32, %[hi], %[lo]"
  36 +               : [lo]"=a"(product),
  37 +                 [hi]"=d"(tmp)
  38 +               : "0"(delta),
  39 +                 [mul_frac]"rm"((u64)mul_frac));
  40  #else
  41  #error implement me!
  42  #endif