Re: [Qemu-ppc] [PATCH] spapr_pci: make index property mandatory

[David Gibson]

On Thu, Sep 14, 2017 at 09:03:15AM +0200, Greg Kurz wrote:
> Creating several PHBs without index property confuses the DRC code
> and causes issues:
> - only the first index-less PHB is functional, the other ones will
>   silently ignore hotplugging of PCI devices
> - QEMU will even terminate if these PHBs have cold-plugged devices
> 
> qemu-system-ppc64: -device virtio-net,bus=pci2.0: an attached device
>  is still awaiting release
> 
> This happens because DR connectors for child PCI devices are created
> with a DRC index that is derived from the PHB's index property. If the
> PHBs are created without index, then the same value of -1 is used to
> compute the DRC indexes for both PHBs, hence causing the collision.
> 
> Also, the index property is used to compute the placement of the PHB's
> memory regions. It is limited to 31 or 255, depending on the machine
> type version. This fits well with the requirements of DRC indexes, which
> need the PHB index to be a 16-bit value.
> 
> This patch hence makes the index property mandatory. As a consequence,
> the PHB's memory regions and BUID are now always configured according
> to the index, and it is no longer possible to set them from the command
> line. We have to introduce a PHB instance init function to initialize
> the 64-bit window address to -1 because pseries-2.7 and older machines
> don't set it.
> 
> This DOES BREAK backwards compat, but we don't think the non-index
> PHB feature was used in practice (at least libvirt doesn't) and the
> simplification is worth it.
> 
> Signed-off-by: Greg Kurz <address@hidden>
> ---
> RFC->v1: - as suggested dy David, updated the changelog to explicitely
>            mention that we intentionally break backwards compat.
> ---
>  hw/ppc/spapr_pci.c |   52 
> ++++++++++------------------------------------------
>  1 file changed, 10 insertions(+), 42 deletions(-)
> 
> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> index cf54160526fa..9a338b7f197b 100644
> --- a/hw/ppc/spapr_pci.c
> +++ b/hw/ppc/spapr_pci.c
> @@ -1523,16 +1523,6 @@ static void spapr_phb_realize(DeviceState *dev, Error 
> **errp)
>          sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(spapr);
>          Error *local_err = NULL;
>  
> -        if ((sphb->buid != (uint64_t)-1) || (sphb->dma_liobn[0] != 
> (uint32_t)-1)
> -            || (sphb->dma_liobn[1] != (uint32_t)-1 && windows_supported == 2)
> -            || (sphb->mem_win_addr != (hwaddr)-1)
> -            || (sphb->mem64_win_addr != (hwaddr)-1)
> -            || (sphb->io_win_addr != (hwaddr)-1)) {
> -            error_setg(errp, "Either \"index\" or other parameters must"
> -                       " be specified for PAPR PHB, not both");
> -            return;
> -        }
> -
>          smc->phb_placement(spapr, sphb->index,
>                             &sphb->buid, &sphb->io_win_addr,
>                             &sphb->mem_win_addr, &sphb->mem64_win_addr,
> @@ -1541,36 +1531,12 @@ static void spapr_phb_realize(DeviceState *dev, Error 
> **errp)
>              error_propagate(errp, local_err);
>              return;
>          }
> -    }
> -
> -    if (sphb->buid == (uint64_t)-1) {
> -        error_setg(errp, "BUID not specified for PHB");
> -        return;
> -    }
> -
> -    if ((sphb->dma_liobn[0] == (uint32_t)-1) ||
> -        ((sphb->dma_liobn[1] == (uint32_t)-1) && (windows_supported > 1))) {
> -        error_setg(errp, "LIOBN(s) not specified for PHB");
> -        return;
> -    }
> -
> -    if (sphb->mem_win_addr == (hwaddr)-1) {
> -        error_setg(errp, "Memory window address not specified for PHB");
> -        return;
> -    }
> -
> -    if (sphb->io_win_addr == (hwaddr)-1) {
> -        error_setg(errp, "IO window address not specified for PHB");
> +    } else {
> +        error_setg(errp, "\"index\" for PAPR PHB is mandatory");
>          return;
>      }
>  
>      if (sphb->mem64_win_size != 0) {
> -        if (sphb->mem64_win_addr == (hwaddr)-1) {
> -            error_setg(errp,
> -                       "64-bit memory window address not specified for PHB");
> -            return;
> -        }
> -
>          if (sphb->mem_win_size > SPAPR_PCI_MEM32_WIN_SIZE) {
>              error_setg(errp, "32-bit memory window of size 0x%"HWADDR_PRIx
>                         " (max 2 GiB)", sphb->mem_win_size);
> @@ -1789,18 +1755,12 @@ static void spapr_phb_reset(DeviceState *qdev)
>  
>  static Property spapr_phb_properties[] = {
>      DEFINE_PROP_UINT32("index", sPAPRPHBState, index, -1),
> -    DEFINE_PROP_UINT64("buid", sPAPRPHBState, buid, -1),
> -    DEFINE_PROP_UINT32("liobn", sPAPRPHBState, dma_liobn[0], -1),
> -    DEFINE_PROP_UINT32("liobn64", sPAPRPHBState, dma_liobn[1], -1),
> -    DEFINE_PROP_UINT64("mem_win_addr", sPAPRPHBState, mem_win_addr, -1),
>      DEFINE_PROP_UINT64("mem_win_size", sPAPRPHBState, mem_win_size,
>                         SPAPR_PCI_MEM32_WIN_SIZE),
> -    DEFINE_PROP_UINT64("mem64_win_addr", sPAPRPHBState, mem64_win_addr, -1),
>      DEFINE_PROP_UINT64("mem64_win_size", sPAPRPHBState, mem64_win_size,
>                         SPAPR_PCI_MEM64_WIN_SIZE),
>      DEFINE_PROP_UINT64("mem64_win_pciaddr", sPAPRPHBState, mem64_win_pciaddr,
>                         -1),
> -    DEFINE_PROP_UINT64("io_win_addr", sPAPRPHBState, io_win_addr, -1),
>      DEFINE_PROP_UINT64("io_win_size", sPAPRPHBState, io_win_size,
>                         SPAPR_PCI_IO_WIN_SIZE),
>      DEFINE_PROP_BOOL("dynamic-reconfiguration", sPAPRPHBState, dr_enabled,
> @@ -1937,6 +1897,13 @@ static const char 
> *spapr_phb_root_bus_path(PCIHostState *host_bridge,
>      return sphb->dtbusname;
>  }
>  
> +static void spapr_phb_instance_init(Object *obj)
> +{
> +    sPAPRPHBState *sphb = SPAPR_PCI_HOST_BRIDGE(obj);
> +
> +    sphb->mem64_win_addr = (hwaddr)-1;
> +}
> +

Why do we need to initialize this field especially?

>  static void spapr_phb_class_init(ObjectClass *klass, void *data)
>  {
>      PCIHostBridgeClass *hc = PCI_HOST_BRIDGE_CLASS(klass);
> @@ -1960,6 +1927,7 @@ static const TypeInfo spapr_phb_info = {
>      .parent        = TYPE_PCI_HOST_BRIDGE,
>      .instance_size = sizeof(sPAPRPHBState),
>      .class_init    = spapr_phb_class_init,
> +    .instance_init = spapr_phb_instance_init,
>      .interfaces    = (InterfaceInfo[]) {
>          { TYPE_HOTPLUG_HANDLER },
>          { }
> 

-- 
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

signature.asc
Description: PGP signature