Re: [PATCH] xio3130_upstream: Add ACS (Access Control Services) capability

[Michael S. Tsirkin]

On Sun, Aug 14, 2022 at 11:59:51PM +0800, Paul Schlacter wrote:
> What's wrong with not disabling the old version?

Old versions have to behave in the same way as they did,
or close enough. Changing that breaks migration between
qemu versions.

> 
> 
> On Sun, Aug 14, 2022 at 6:48 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> 
>     On Sun, Aug 14, 2022 at 03:47:49PM +0800, Paul Schlacter wrote:
>     > If it is a pcie device, check that all devices on the path from
>     >
>     > the device to the root complex have ACS enabled, and then the
>     >
>     > device will become an iommu_group.
>     >
>     > it will have the effect of isolation
>     >
>     >
>     > Signed-off-by: wlfightup <wlfightup@gmail.com>
> 
>     I don't think we can do this unconditionally. Has to have
>     a property and disabled for old versions.
> 
>     > ---
>     >
>     >  hw/pci-bridge/xio3130_upstream.c | 3 +++
>     >
>     >  1 file changed, 3 insertions(+)
>     >
>     >
>     > diff --git a/hw/pci-bridge/xio3130_upstream.c b/hw/pci-bridge/
>     > xio3130_upstream.c
>     >
>     > index 5ff46ef050..2df952222b 100644
>     >
>     > --- a/hw/pci-bridge/xio3130_upstream.c
>     >
>     > +++ b/hw/pci-bridge/xio3130_upstream.c
>     >
>     > @@ -37,6 +37,8 @@
>     >
>     >  #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_upstream_write_config(PCIDevice *d, uint32_t
>     address,
>     >
>     >                                            uint32_t val, int len)
>     >
>     > @@ -92,6 +94,7 @@ static void xio3130_upstream_realize(PCIDevice *d,
>     Error
>     > **errp)
>     >
>     >          goto err;
>     >
>     >      }
>     >
>     >
>     > +    pcie_acs_init(d, XIO3130_ACS_OFFSET);
>     >
>     >      return;
>     >
>     >
>     >  err:
>     >
>     > --
>     >
>     > 2.24.3 (Apple Git-128)
>     >
> 
>