[PATCH 1/6] KVM: x86: bit-ops emulation ignores offset on 64-bit

Nadav Amit
2014-06-15T13:12:57Z

The current emulation of bit operations ignores the offset from the destination
on 64-bit target memory operands. This patch fixes this behavior.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
---
arch/x86/kvm/emulate.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index e4e833d..f0b0a10 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1220,12 +1220,14 @@ static void fetch_bit_operand(struct x86_emulate_ctxt *ctxt)
long sv = 0, mask;

if (ctxt->dst.type == OP_MEM && ctxt->src.type == OP_REG) {
- mask = ~(ctxt->dst.bytes * 8 - 1);
+ mask = ~((long)ctxt->dst.bytes * 8 - 1);

if (ctxt->src.bytes == 2)
sv = (s16)ctxt->src.val & (s16)mask;
else if (ctxt->src.bytes == 4)
sv = (s32)ctxt->src.val & (s32)mask;
+ else
+ sv = (s64)ctxt->src.val & (s64)mask;

ctxt->dst.addr.mem.ea += (sv >> 3);
}
--
1.9.1