| Message ID | 1566911210-30059-3-git-send-email-jan.dakinevich@virtuozzo.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fix emulation error on Windows bootup | expand |
On Tue, Aug 27, 2019 at 01:07:08PM +0000, Jan Dakinevich wrote: > x86_emulate_instruction() takes into account ctxt->have_exception flag > during instruction decoding, but in practice this flag is never set in > x86_decode_insn(). > > Fixes: 6ea6e84 ("KVM: x86: inject exceptions produced by x86_decode_insn") > Cc: Denis Lunev <den@virtuozzo.com> > Cc: Roman Kagan <rkagan@virtuozzo.com> > Cc: Denis Plotnikov <dplotnikov@virtuozzo.com> > Signed-off-by: Jan Dakinevich <jan.dakinevich@virtuozzo.com> > --- > arch/x86/kvm/emulate.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c > index 6170ddf..f93880f 100644 > --- a/arch/x86/kvm/emulate.c > +++ b/arch/x86/kvm/emulate.c > @@ -5395,6 +5395,8 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) > ctxt->memopp->addr.mem.ea + ctxt->_eip); > > done: > + if (rc == X86EMUL_PROPAGATE_FAULT) > + ctxt->have_exception = true; We should add a sanity check or two on the vector since the emulator code goes all over the place, e.g. #UD should not be injected/propagated, and trap-like exceptions should not be handled/encountered during decode. Note, exception_type() also warns on illegal vectors. WARN_ON_ONCE(ctxt->exception.vector == UD_VECTOR || exception_type(ctxt->exception.vector) == EXCPT_TRAP); > return (rc != X86EMUL_CONTINUE) ? EMULATION_FAILED : EMULATION_OK; > } > > -- > 2.1.4 >
On Tue, 27 Aug 2019 07:53:58 -0700 Sean Christopherson <sean.j.christopherson@intel.com> wrote: > On Tue, Aug 27, 2019 at 01:07:08PM +0000, Jan Dakinevich wrote: > > x86_emulate_instruction() takes into account ctxt->have_exception flag > > during instruction decoding, but in practice this flag is never set in > > x86_decode_insn(). > > > > Fixes: 6ea6e84 ("KVM: x86: inject exceptions produced by x86_decode_insn") > > Cc: Denis Lunev <den@virtuozzo.com> > > Cc: Roman Kagan <rkagan@virtuozzo.com> > > Cc: Denis Plotnikov <dplotnikov@virtuozzo.com> > > Signed-off-by: Jan Dakinevich <jan.dakinevich@virtuozzo.com> > > --- > > arch/x86/kvm/emulate.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c > > index 6170ddf..f93880f 100644 > > --- a/arch/x86/kvm/emulate.c > > +++ b/arch/x86/kvm/emulate.c > > @@ -5395,6 +5395,8 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) > > ctxt->memopp->addr.mem.ea + ctxt->_eip); > > > > done: > > + if (rc == X86EMUL_PROPAGATE_FAULT) > > + ctxt->have_exception = true; > > We should add a sanity check or two on the vector since the emulator code > goes all over the place, e.g. #UD should not be injected/propagated, and > trap-like exceptions should not be handled/encountered during decode. > Note, exception_type() also warns on illegal vectors. > > WARN_ON_ONCE(ctxt->exception.vector == UD_VECTOR || > exception_type(ctxt->exception.vector) == EXCPT_TRAP); Ok. > > > return (rc != X86EMUL_CONTINUE) ? EMULATION_FAILED : EMULATION_OK; > > } > > > > -- > > 2.1.4 > >
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 6170ddf..f93880f 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -5395,6 +5395,8 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) ctxt->memopp->addr.mem.ea + ctxt->_eip); done: + if (rc == X86EMUL_PROPAGATE_FAULT) + ctxt->have_exception = true; return (rc != X86EMUL_CONTINUE) ? EMULATION_FAILED : EMULATION_OK; }
x86_emulate_instruction() takes into account ctxt->have_exception flag during instruction decoding, but in practice this flag is never set in x86_decode_insn(). Fixes: 6ea6e84 ("KVM: x86: inject exceptions produced by x86_decode_insn") Cc: Denis Lunev <den@virtuozzo.com> Cc: Roman Kagan <rkagan@virtuozzo.com> Cc: Denis Plotnikov <dplotnikov@virtuozzo.com> Signed-off-by: Jan Dakinevich <jan.dakinevich@virtuozzo.com> --- arch/x86/kvm/emulate.c | 2 ++ 1 file changed, 2 insertions(+)