| Message ID | 1435722703-12515-1-git-send-email-david@gibson.dropbear.id.au |
|---|---|
| State | New |
| Headers | show |
Ugh, sorry, this version is buggy, I'll resend. On Wed, Jul 01, 2015 at 01:51:43PM +1000, David Gibson wrote: > From: Greg Kurz <gkurz@linux.vnet.ibm.com> > > If a guest passes the reg property of a valid VIO object that is not a VTY > to either H_GET_TERM_CHAR or H_PUT_TERM_CHAR, QEMU hits a dynamic cast > assertion and aborts. > > PAPR+ says "Hypervisor checks the termno parameter for validity against the > Vterm IOA unit addresses assigned to the partition, else return H_Parameter." > > This patch adds a type check to ensure vty_lookup() either returns a pointer > to a valid VTY object or NULL. H_GET_TERM_CHAR and H_PUT_TERM_CHAR will > now return H_PARAMETER to the guest instead of crashing. > > The patch has no effect on the reg == 0 hack used to implement the RTAS call > display-character. > > Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com> > Signed-off-by: David Gibson <david@gibson.dropbear.id.au> > --- > hw/char/spapr_vty.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > I've already merged this into spapr-next and it will be in the next > batch I send if not merged before that. > > But I think this is an important enough fix (it allows the guest to > crash qemu) that it should probably be fastracked into mainline and > stable. > > diff --git a/hw/char/spapr_vty.c b/hw/char/spapr_vty.c > index 1d53035..f407cd0 100644 > --- a/hw/char/spapr_vty.c > +++ b/hw/char/spapr_vty.c > @@ -228,7 +228,7 @@ VIOsPAPRDevice *vty_lookup(sPAPRMachineState *spapr, target_ulong reg) > return spapr_vty_get_default(spapr->vio_bus); > } > > - return sdev; > + return object_dynamic_cast(sdev, TYPE_VIO_SPAPR_VTY_DEVICE); > } > > static void spapr_vty_register_types(void)
diff --git a/hw/char/spapr_vty.c b/hw/char/spapr_vty.c index 1d53035..f407cd0 100644 --- a/hw/char/spapr_vty.c +++ b/hw/char/spapr_vty.c @@ -228,7 +228,7 @@ VIOsPAPRDevice *vty_lookup(sPAPRMachineState *spapr, target_ulong reg) return spapr_vty_get_default(spapr->vio_bus); } - return sdev; + return object_dynamic_cast(sdev, TYPE_VIO_SPAPR_VTY_DEVICE); } static void spapr_vty_register_types(void)