KVM: x86: bit-ops emulation ignores offset on 64-bit

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>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 8a1796b1eef2..439a3286406a 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);
         }