Hi Markus, On 10/10/2016 14:36, Markus Armbruster wrote: > Auger Eric <eric.au...@redhat.com> writes: > >> Hi, >> >> On 10/10/2016 07:34, David Gibson wrote: >>> On Fri, Oct 07, 2016 at 09:36:09AM +0200, Auger Eric wrote: >>>> Hi, >>>> >>>> On 07/10/2016 09:01, Markus Armbruster wrote: >>>>> Eric Auger <eric.au...@redhat.com> writes: >>>>> >>>>>> The error is currently simply reported in vfio_get_group. Don't >>>>>> bother too much with the prefix which will be handled at upper level, >>>>>> later on. >>>>>> >>>>>> Also return an error value in case container->error is not 0 and >>>>>> the container is teared down. >>>>> >>>>> "torn down", I think. >>>> >>>> Sure. I had a wrong feeling when writing this ... >>>>> >>>>> Is this a bug fix? See also below. >>>>> >>>>>> On vfio_spapr_remove_window failure, we also report an error whereas >>>>>> it was silent before. >>>>>> >>>>>> Signed-off-by: Eric Auger <eric.au...@redhat.com> >>>>>> Reviewed-by: Markus Armbruster <arm...@redhat.com> >>>>>> >>>>>> --- >>>>>> >>>>>> v4 -> v5: >>>>>> - set ret to container->error >>>>>> - mention error report on vfio_spapr_remove_window failure in the commit >>>>>> message >>>>>> --- >>>>>> hw/vfio/common.c | 40 +++++++++++++++++++++++++--------------- >>>>>> 1 file changed, 25 insertions(+), 15 deletions(-) >>>>>> >>>>>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c >>>>>> index 29188a1..85a7759 100644 >>>>>> --- a/hw/vfio/common.c >>>>>> +++ b/hw/vfio/common.c > [...] >>>>>> @@ -1008,7 +1010,9 @@ static int vfio_connect_container(VFIOGroup >>>>>> *group, AddressSpace *as) > container = g_malloc0(sizeof(*container)); > container->space = space; > container->fd = fd; > if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU) || > ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1v2_IOMMU)) { > [...] > } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU) || > ioctl(fd, VFIO_CHECK_EXTENSION, > VFIO_SPAPR_TCE_v2_IOMMU)) { > struct vfio_iommu_spapr_tce_info info; > bool v2 = !!ioctl(fd, VFIO_CHECK_EXTENSION, > VFIO_SPAPR_TCE_v2_IOMMU); > > ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd); > if (ret) { > error_setg_errno(errp, errno, "failed to set group > container"); > ret = -errno; > goto free_container_exit; > } > container->iommu_type = > v2 ? VFIO_SPAPR_TCE_v2_IOMMU : VFIO_SPAPR_TCE_IOMMU; > ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type); > if (ret) { > error_setg_errno(errp, errno, "failed to set iommu for > container"); > ret = -errno; > goto free_container_exit; > } > > /* > * The host kernel code implementing VFIO_IOMMU_DISABLE is > called > * when container fd is closed so we do not call it explicitly > * in this file. > */ > if (!v2) { > ret = ioctl(fd, VFIO_IOMMU_ENABLE); > if (ret) { > error_setg_errno(errp, errno, "failed to enable > container"); > ret = -errno; > goto free_container_exit; > } > } else { > container->prereg_listener = vfio_prereg_listener; > > memory_listener_register(&container->prereg_listener, >>>>>> &address_space_memory); >>>>>> if (container->error) { >>>>> >>>>> I tried to see where non-zero container->error comes from, but failed. >>>>> Can you help? >>>> >>>> Added Alexey in CC >>>> >>>> It is set in vfio_prereg_listener_region_add (spapr.c) >>>> There is a comment there saying: >>>> /* >>>> * On the initfn path, store the first error in the container so we >>>> * can gracefully fail. Runtime, there's not much we can do other >>>> * than throw a hardware error. >>>> */ >>>> 1) by the way I should also s/initfn/realize now. >>>> 2) by gracefully fail I understand the error should be properly >>>> cascaded. Also when looking at the other vfio_memory_listener >>>> registration below, ret is set to container->error. >>>> 3) I could use error_setg_errno ... >>>> >>>> David, Alexey, could you confirm we should set the returned value to the >>>> container->error below? >>> >>> I think the right approach is to change container->error from an int >>> to an Error *. As now, we stash the first error from the listener in >>> there. >>> >>> realize() would check for a non-NULL error in the container after >>> registering the listener, and if present, propagate it up to the >>> caller. >>> >>>> >>>> Thanks >>>> >>>> Eric >>>> >>>> >>>>> >>>>>> memory_listener_unregister(&container->prereg_listener); >>>>>> - error_report("vfio: RAM memory listener initialization >>>>>> failed for container"); >>>>>> + ret = container->error; >> Thank you for your answers. OK to change container->error from an int >> to an Error *. >> >> So I understand the fix just above is correct, ie. consider a non-NULL >> container->error as an error that should be cascaded to the caller. >> Currently I understand it is not since ret was left to 0. > > If whatever sets container->error now can provide more useful error > information by setting an Error, then replacing VFIOContainer member int > error by Error *err makes sense. Else, I recommend to keep it simple > and stick to errno codes. > > My original question was about something else: I can't see what could > have set container->error here. Have a look at the additional context I > quoted above. Initially, container->error is zero. The ioctl()'s can't > change it. That leaves memory_listener_register(). How can > container->error be set? My understanding is on memory_listener_register(&container->prereg_listener, &address_space_memory);
you get the vfio_prereg_listener_region_add called which is likely to set container->error with the returned value of VFIO_IOMMU_SPAPR_REGISTER_MEMORY ioctl. Do I miss something? Thanks Eric >