Re: [Qemu-devel] [PATCH 1/2] pcie_root_port: Allow ACS to be disabled

[Igor Mammedov]

On Tue, 30 Jul 2019 10:37:18 +0100
"Dr. David Alan Gilbert (git)" <address@hidden> wrote:

> From: "Dr. David Alan Gilbert" <address@hidden>
> 
> ACS was added in 4.0 unconditionally, this breaks migration
> compatibility.
> Allow ACS to be disabled by adding a property that's
> checked by pcie_root_port.
> 
> Unfortunately pcie-root-port doesn't have any instance data,
> so there's no where for that flag to live, so stuff it into
> PCIESlot.
> 
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> ---
>  hw/pci-bridge/pcie_root_port.c | 3 ++-
>  include/hw/pci/pcie_port.h     | 2 ++
>  2 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/pci-bridge/pcie_root_port.c b/hw/pci-bridge/pcie_root_port.c
> index 09019ca05d..1d8a778709 100644
> --- a/hw/pci-bridge/pcie_root_port.c
> +++ b/hw/pci-bridge/pcie_root_port.c
> @@ -111,7 +111,7 @@ static void rp_realize(PCIDevice *d, Error **errp)
>      pcie_aer_root_init(d);
>      rp_aer_vector_update(d);
>  
> -    if (rpc->acs_offset) {
> +    if (rpc->acs_offset && !s->disable_acs) {

it's not like it would be used per instance,
so could we use class property and with rpc->disable_acs instead of PCIESlot?

>          pcie_acs_init(d, rpc->acs_offset);
>      }
>      return;
> @@ -145,6 +145,7 @@ static void rp_exit(PCIDevice *d)
>  static Property rp_props[] = {
>      DEFINE_PROP_BIT(COMPAT_PROP_PCP, PCIDevice, cap_present,
>                      QEMU_PCIE_SLTCAP_PCP_BITNR, true),
> +    DEFINE_PROP_BOOL("disable-acs", PCIESlot, disable_acs, false),
>      DEFINE_PROP_END_OF_LIST()
>  };
>  
> diff --git a/include/hw/pci/pcie_port.h b/include/hw/pci/pcie_port.h
> index 09586f4641..7515430087 100644
> --- a/include/hw/pci/pcie_port.h
> +++ b/include/hw/pci/pcie_port.h
> @@ -53,6 +53,8 @@ struct PCIESlot {
>      PCIExpLinkSpeed speed;
>      PCIExpLinkWidth width;
>  
> +    /* Disable ACS (really for a pcie_root_port) */
> +    bool        disable_acs;
>      QLIST_ENTRY(PCIESlot) next;
>  };
>