On Sat, Oct 14, 2017 at 10:52:45AM +0200, Auger Eric wrote: > Hi Christoffer, > > On 13/10/2017 19:56, Christoffer Dall wrote: > > On Fri, Oct 13, 2017 at 04:22:25PM +0200, Auger Eric wrote: > >> Hi, > >> > >> On 13/10/2017 15:16, Christoffer Dall wrote: > >>> On Wed, Sep 27, 2017 at 03:28:33PM +0200, Eric Auger wrote: > >>>> At the moment the device table save() returns -EINVAL if > >>>> vgic_its_check_id() fails to return the gpa of the entry > >>>> associated to the device/collection id. Let vgic_its_check_id() > >>>> return an int instead of a bool and return a more precised > >>>> error value: > >>>> - EINVAL in case the id is out of range > >>>> - EFAULT if the gpa is not provisionned or is not valid > >>>> > >>> > >>> This is just to ease debugging, yes? > >> > >> I understood user-space should be able to discriminate between bad guest > >> programming and values corrupted by the userspace (regs for instance). > >> In first case QEMU should not abort. In latter case it should abort. > > > > So what is userspace supposed to do in the first case? > > I was referring to https://www.spinics.net/lists/kvm/msg148791.html. > QEMU is supposed to write a message in that case but not cause an abort(). > > This is what is actually implemented on QEMU side. In case the ioctl > returns -EFAULT, we don't abort but simply warn. However at the moment > we return -EINVAL in some circumstances where - I think - we should > return -EFAULT. Hence this patch attempting to be more precise on the > cause of the failure instead of abruptly returning -EINVAL here. > ok, thanks makes sense. Thanks for sharing the background. -Christoffer
