[libvirt] [PATCH 03/11] conf: Remove dubious code from virDomainPCIAddressSetGrow()

[John Ferlan]

On 03/28/2018 10:06 AM, Andrea Bolognani wrote:
> I haven't been able to come up with a single scenario in which
> the code in question would be executed; even if there was one,
> it would be due to the user specifying a *partial* PCI topology
> in the guest XML, which is of course entirely unsupportable and
> thus providing even the slightest hint that doing so is in any
> way a good idea is actively harmful.
> 
> Signed-off-by: Andrea Bolognani <abologna at redhat.com>
> ---
>  src/conf/domain_addr.c | 9 ---------
>  1 file changed, 9 deletions(-)
> 

Since Laine added this code - perhaps calling his name out on the CC
list will allow him to appear and answer the question. Although it could
take 3 such utterances (e.g. beetlejuice)...

Personally, it seems reasonable and you didn't have to change any test
output, but PCI connection requirements are black boxes to me. I know I
cannot plug my US plug into the CZ outlets, but when it comes to PCI
connection rules - I'm glad someone else knows them!

A soft and mostly unqualified,

Reviewed-by: John Ferlan <jferlan at redhat.com>

John

> diff --git a/src/conf/domain_addr.c b/src/conf/domain_addr.c
> index 0c914fe25c..18b6f8d588 100644
> --- a/src/conf/domain_addr.c
> +++ b/src/conf/domain_addr.c
> @@ -447,15 +447,6 @@ virDomainPCIAddressSetGrow(virDomainPCIAddressSetPtr addrs,
>                  addr->bus++;
>              }
>          }
> -    } else if (flags & VIR_PCI_CONNECT_TYPE_PCI_BRIDGE &&
> -               addrs->buses[0].model == VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT) {
> -        /* NB: if the root bus is pci-root, and we couldn't find an
> -         * open place to connect a pci-bridge, then there is nothing
> -         * we can do (since the only way to gain a new slot that
> -         * accepts a pci-bridge is to add *a pci-bridge* (which is the
> -         * reason we're here in the first place!)
> -         */
> -        model = VIR_DOMAIN_CONTROLLER_MODEL_DMI_TO_PCI_BRIDGE;
>      } else if (flags & (VIR_PCI_CONNECT_TYPE_PCIE_DEVICE |
>                          VIR_PCI_CONNECT_TYPE_PCIE_SWITCH_UPSTREAM_PORT)) {
>          model = VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT_PORT;
>