diff options
| author | Wei Yongjun <yjwei@cn.fujitsu.com> | 2010-08-09 11:34:56 +0800 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2010-10-24 10:51:01 +0200 |
| commit | 35c843c4857e2a818d1d951d87c40ee2cf5c1be8 (patch) | |
| tree | 3af2786b912d11c373c5eed7df590070bce089b3 /arch/x86/kvm | |
| parent | 8744aa9aad56be756a58126b429f176898631c3f (diff) | |
KVM: x86 emulator: fix negative bit offset BitOp instruction emulation
If bit offset operands is a negative number, BitOp instruction
will return wrong value. This patch fix it.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 175b41690d6f..5fc441c064ba 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -723,6 +723,22 @@ done: return rc; } +static void fetch_bit_operand(struct decode_cache *c) +{ + long sv, mask; + + if (c->dst.type == OP_MEM) { + mask = ~(c->dst.bytes * 8 - 1); + + if (c->src.bytes == 2) + sv = (s16)c->src.val & (s16)mask; + else if (c->src.bytes == 4) + sv = (s32)c->src.val & (s32)mask; + + c->dst.addr.mem += (sv >> 3); + } +} + static int read_emulated(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops, unsigned long addr, void *dest, unsigned size) @@ -2638,12 +2654,8 @@ done_prefixes: c->dst.bytes = 8; else c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes; - if (c->dst.type == OP_MEM && (c->d & BitOp)) { - unsigned long mask = ~(c->dst.bytes * 8 - 1); - - c->dst.addr.mem = c->dst.addr.mem + - (c->src.val & mask) / 8; - } + if (c->d & BitOp) + fetch_bit_operand(c); c->dst.orig_val = c->dst.val; break; case DstAcc: |