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author | Nadav Amit <namit@cs.technion.ac.il> | 2014-04-18 02:35:10 +0200 |
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committer | Marcelo Tosatti <mtosatti@redhat.com> | 2014-04-23 22:46:59 +0200 |
commit | e6e39f0438bc4b0da9334ca42337775c7a00db21 (patch) | |
tree | f45f3cd73bf5dfed71656891368654f3cc6c9bab | |
parent | KVM: x86: Fix CR3 reserved bits (diff) | |
download | linux-e6e39f0438bc4b0da9334ca42337775c7a00db21.tar.xz linux-e6e39f0438bc4b0da9334ca42337775c7a00db21.zip |
KVM: x86: IN instruction emulation should ignore REP-prefix
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>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
-rw-r--r-- | arch/x86/kvm/emulate.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index f3834bbca1d7..e8a58409b5ac 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; |