Commit de2d1a52 authored by Zachary Amsden's avatar Zachary Amsden Committed by Avi Kivity

KVM: Fix register corruption in pvclock_scale_delta

The 128-bit multiply in pvclock.h was missing an output constraint for
EDX which caused a register corruption to appear.  Thanks to Ulrich for
diagnosing the EDX corruption and Avi for providing this fix.
Signed-off-by: default avatarZachary Amsden <zamsden@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent a0a8eaba
......@@ -22,6 +22,8 @@ static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
u64 product;
#ifdef __i386__
u32 tmp1, tmp2;
#else
ulong tmp;
#endif
if (shift < 0)
......@@ -42,8 +44,11 @@ static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
: "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
#elif defined(__x86_64__)
__asm__ (
"mul %%rdx ; shrd $32,%%rdx,%%rax"
: "=a" (product) : "0" (delta), "d" ((u64)mul_frac) );
"mul %[mul_frac] ; shrd $32, %[hi], %[lo]"
: [lo]"=a"(product),
[hi]"=d"(tmp)
: "0"(delta),
[mul_frac]"rm"((u64)mul_frac));
#else
#error implement me!
#endif
......
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