Re: [PULL 12/65] hw/acpi: Generic Port Affinity Structure support

[Michael S. Tsirkin]

On Tue, Nov 05, 2024 at 09:06:26AM +0000, Daniel P. Berrangé wrote:
> On Mon, Nov 04, 2024 at 04:06:16PM -0500, Michael S. Tsirkin wrote:
> > From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> > 
> > These are very similar to the recently added Generic Initiators
> > but instead of representing an initiator of memory traffic they
> > represent an edge point beyond which may lie either targets or
> > initiators.  Here we add these ports such that they may
> > be targets of hmat_lb records to describe the latency and
> > bandwidth from host side initiators to the port.  A discoverable
> > mechanism such as UEFI CDAT read from CXL devices and switches
> > is used to discover the remainder of the path, and the OS can build
> > up full latency and bandwidth numbers as need for work and data
> > placement decisions.
> > 
> > Acked-by: Markus Armbruster <armbru@redhat.com>
> > Tested-by: "Huang, Ying" <ying.huang@intel.com>
> > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> > Message-Id: <20240916174122.1843197-1-Jonathan.Cameron@huawei.com>
> > Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> >  qapi/qom.json                       |  41 ++++++++++
> >  include/hw/acpi/aml-build.h         |   3 +
> >  include/hw/acpi/pci.h               |   2 +-
> >  include/hw/pci/pci_bridge.h         |   1 +
> >  hw/acpi/aml-build.c                 |  39 ++++++++++
> >  hw/acpi/pci.c                       | 116 +++++++++++++++++++++++++++-
> >  hw/arm/virt-acpi-build.c            |   2 +-
> >  hw/i386/acpi-build.c                |   2 +-
> >  hw/pci-bridge/pci_expander_bridge.c |   1 -
> >  9 files changed, 202 insertions(+), 5 deletions(-)
> > 
> > diff --git a/qapi/qom.json b/qapi/qom.json
> > index 321ccd708a..a8beeabf1f 100644
> > --- a/qapi/qom.json
> > +++ b/qapi/qom.json
> > @@ -844,6 +844,45 @@
> >    'data': { 'pci-dev': 'str',
> >              'node': 'uint32' } }
> >  
> > +##
> > +# @AcpiGenericPortProperties:
> > +#
> > +# Properties for acpi-generic-port objects.
> > +#
> > +# @pci-bus: QOM path of the PCI bus of the hostbridge associated with
> > +#     this SRAT Generic Port Affinity Structure.  This is the same as
> > +#     the bus parameter for the root ports attached to this host
> > +#     bridge.  The resulting SRAT Generic Port Affinity Structure will
> > +#     refer to the ACPI object in DSDT that represents the host bridge
> > +#     (e.g.  ACPI0016 for CXL host bridges).  See ACPI 6.5 Section
> > +#     5.2.16.7 for more information.
> > +#
> > +# @node: Similar to a NUMA node ID, but instead of providing a
> > +#     reference point used for defining NUMA distances and access
> > +#     characteristics to memory or from an initiator (e.g. CPU), this
> > +#     node defines the boundary point between non-discoverable system
> > +#     buses which must be described by firmware, and a discoverable
> > +#     bus.  NUMA distances and access characteristics are defined to
> > +#     and from that point.  For system software to establish full
> > +#     initiator to target characteristics this information must be
> > +#     combined with information retrieved from the discoverable part
> > +#     of the path.  An example would use CDAT (see UEFI.org)
> > +#     information read from devices and switches in conjunction with
> > +#     link characteristics read from PCIe Configuration space.
> > +#     To get the full path latency from CPU to CXL attached DRAM
> > +#     CXL device:  Add the latency from CPU to Generic Port (from
> > +#     HMAT indexed via the the node ID in this SRAT structure) to
> > +#     that for CXL bus links, the latency across intermediate switches
> > +#     and from the EP port to the actual memory.  Bandwidth is more
> > +#     complex as there may be interleaving across multiple devices
> > +#     and shared links in the path.
> > +#
> > +# Since: 9.1
> 
> This is outdated, we're in the 9.2 dev cycle currently.


Jonathan can you fix this up pls?

> 
> With regards,
> Daniel
> -- 
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