Messages in this thread Patch in this message | | | From | Nadav Amit <> | Subject | [PATCH 3/5] KVM: x86: IN instruction emulation should ignore REP-prefix | Date | Fri, 18 Apr 2014 03:35:10 +0300 |
| |
The IN instruction is not be affected by REP-prefix as INS is. Therefore, the emulation should ignore the REP prefix as well. The current emulator implementation tries to perform writeback when IN instruction with REP-prefix is emulated. This causes it to perform wrong memory write or spurious #GP exception to be injected to the guest.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> --- :100644 100644 1d60374... 69e2636... M arch/x86/kvm/emulate.c arch/x86/kvm/emulate.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 1d60374..69e2636 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1324,7 +1324,8 @@ static int pio_in_emulated(struct x86_emulate_ctxt *ctxt, rc->end = n * size; } - if (ctxt->rep_prefix && !(ctxt->eflags & EFLG_DF)) { + if (ctxt->rep_prefix && (ctxt->d & String) && + !(ctxt->eflags & EFLG_DF)) { ctxt->dst.data = rc->data + rc->pos; ctxt->dst.type = OP_MEM_STR; ctxt->dst.count = (rc->end - rc->pos) / size; -- 1.7.10.4
| |