On Thu, Aug 22, 2019 at 04:59:18PM -0300, Daniel Henrique Barboza wrote: > There is nothing wrong with how sPAPR handles multifunction PCI > hot unplugs. The problem is that x86 does it simpler. Instead of > removing each non-zero function and then removing function zero, > x86 can remove any function of the slot to trigger the hot unplug. > > Libvirt will be directly impacted by this difference, in the > (hopefully soon) PCI Multifunction hot plug/unplug support. For > hot plugs, both x86 and sPAPR will operate the same way: a XML > with all desired functions to be added, then consecutive hotplugs > of all non-zero functions first, zero last. For hot unplugs, at > least in the current state, a XML with the devices to be removed > must also be provided because of how sPAPR operates - x86 does > not need it - since any function unplug will unplug the whole > PCIe slot. This difference puts extra strain in the management > layer, which needs to either handle both archs differently in > the unplug scenario or choose treat x86 like sPAPR, forcing x86 > users to cope with sPAPR internals. > > This patch changes spapr_pci_unplug_request to handle the > unplug of function zero differently. When removing function zero, > instead of error-ing out if there are any remaining function > DRCs which needs detaching, detach those. This has no effect in > any existing scripts that are detaching the non-zero functions > before function zero, and can be used by management as a shortcut > to remove the whole PCI multifunction device without specifying > each child function.
Makes sense to me, applied to ppc-for-4.2.
>
> Signed-off-by: Daniel Henrique Barboza <danielhb...@gmail.com>
> ---
> hw/ppc/spapr_pci.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> index deb0b0c80c..9f176f463e 100644
> --- a/hw/ppc/spapr_pci.c
> +++ b/hw/ppc/spapr_pci.c
> @@ -1700,11 +1700,13 @@ static void spapr_pci_unplug_request(HotplugHandler
> *plug_handler,
> state = func_drck->dr_entity_sense(func_drc);
> if (state == SPAPR_DR_ENTITY_SENSE_PRESENT
> && !spapr_drc_unplug_requested(func_drc)) {
> - error_setg(errp,
> - "PCI: slot %d, function %d still present. "
> - "Must unplug all non-0 functions first.",
> - slotnr, i);
> - return;
> + /*
> + * Attempting to remove function 0 of a multifunction
> + * device will will cascade into removing all child
> + * functions, even if their unplug weren't requested
> + * beforehand.
> + */
> + spapr_drc_detach(func_drc);
> }
> }
> }
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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