Re: [PATCH] xio3130_downstream: Add ACS (Access Control Services) capability

[Paul Schlacter]

ping

On Tue, Jan 31, 2023 at 2:30 PM wlfightup <wlfightup@gmail.com> wrote:
>
> When vfio-pci devices are attached to the downstream, pcie acs
> capability may be needed, Consistent with physical machine.
>
> It has been tested in our environment, and pcie acs capability
> is required in some scenarios.
>
> Claim ACS support in the downstream port to allow
> passthrough of individual functions of a device to different
> guests (in a nested virt.setting) with VFIO.
> Without this patch, all functions of a device, such as all VFs of
> an SR/IOV device, will end up in the same IOMMU group.
> A similar situation occurs on Windows with Hyper-V.
>
> Signed-off-by: wlfightup <wlfightup@gmail.com>
> ---
>  hw/pci-bridge/xio3130_downstream.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/hw/pci-bridge/xio3130_downstream.c 
> b/hw/pci-bridge/xio3130_downstream.c
> index 38a2361fa2..2017cf42a3 100644
> --- a/hw/pci-bridge/xio3130_downstream.c
> +++ b/hw/pci-bridge/xio3130_downstream.c
> @@ -40,6 +40,8 @@
>  #define XIO3130_SSVID_SSID              0
>  #define XIO3130_EXP_OFFSET              0x90
>  #define XIO3130_AER_OFFSET              0x100
> +#define XIO3130_ACS_OFFSET \
> +        (XIO3130_AER_OFFSET + PCI_ERR_SIZEOF)
>
>  static void xio3130_downstream_write_config(PCIDevice *d, uint32_t address,
>                                           uint32_t val, int len)
> @@ -111,6 +113,10 @@ static void xio3130_downstream_realize(PCIDevice *d, 
> Error **errp)
>          goto err;
>      }
>
> +    if (!s->disable_acs) {
> +        pcie_acs_init(d, XIO3130_ACS_OFFSET);
> +    }
> +
>      return;
>
>  err:
> @@ -137,6 +143,7 @@ static void xio3130_downstream_exitfn(PCIDevice *d)
>  static Property xio3130_downstream_props[] = {
>      DEFINE_PROP_BIT(COMPAT_PROP_PCP, PCIDevice, cap_present,
>                      QEMU_PCIE_SLTCAP_PCP_BITNR, true),
> +    DEFINE_PROP_BOOL("x-disable-acs", PCIESlot, disable_acs, true),
>      DEFINE_PROP_END_OF_LIST()
>  };
>
> --
> 2.24.3 (Apple Git-128)
>