hw/acpi: Implement the SRAT GI affinity structure

ACPI spec provides a scheme to associate "Generic Initiators" [1]
(e.g. heterogeneous processors and accelerators, GPUs, and I/O devices with
integrated compute or DMA engines GPUs) with Proximity Domains. This is
achieved using Generic Initiator Affinity Structure in SRAT. During bootup,
Linux kernel parse the ACPI SRAT to determine the PXM ids and create a NUMA
node for each unique PXM ID encountered. Qemu currently do not implement
these structures while building SRAT.

Add GI structures while building VM ACPI SRAT. The association between
device and node are stored using acpi-generic-initiator object. Lookup
presence of all such objects and use them to build these structures.

The structure needs a PCI device handle [2] that consists of the device BDF.
The vfio-pci device corresponding to the acpi-generic-initiator object is
located to determine the BDF.

[1] ACPI Spec 6.3, Section 5.2.16.6
[2] ACPI Spec 6.3, Table 5.80

Cc: Jonathan Cameron <qemu-devel@nongnu.org>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Cedric Le Goater <clg@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Ankit Agrawal <ankita@nvidia.com>
Message-Id: <20240308145525.10886-3-ankita@nvidia.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/acpi/acpi_generic_initiator.c

@@ -5,7 +5,9 @@
 
 #include "qemu/osdep.h"
 #include "hw/acpi/acpi_generic_initiator.h"
+#include "hw/acpi/aml-build.h"
 #include "hw/boards.h"
+#include "hw/pci/pci_device.h"
 #include "qemu/error-report.h"
 
 typedef struct AcpiGenericInitiatorClass {
@@ -47,6 +49,7 @@ static void acpi_generic_initiator_set_node(Object *obj, Visitor *v,
                                             Error **errp)
 {
     AcpiGenericInitiator *gi = ACPI_GENERIC_INITIATOR(obj);
+    MachineState *ms = MACHINE(qdev_get_machine());
     uint32_t value;
 
     if (!visit_type_uint32(v, name, &value, errp)) {
@@ -60,6 +63,7 @@ static void acpi_generic_initiator_set_node(Object *obj, Visitor *v,
     }
 
     gi->node = value;
+    ms->numa_state->nodes[gi->node].has_gi = true;
 }
 
 static void acpi_generic_initiator_class_init(ObjectClass *oc, void *data)
@@ -69,3 +73,76 @@ static void acpi_generic_initiator_class_init(ObjectClass *oc, void *data)
     object_class_property_add(oc, "node", "int", NULL,
         acpi_generic_initiator_set_node, NULL, NULL);
 }
+
+/*
+ * ACPI 6.3:
+ * Table 5-78 Generic Initiator Affinity Structure
+ */
+static void
+build_srat_generic_pci_initiator_affinity(GArray *table_data, int node,
+                                          PCIDeviceHandle *handle)
+{
+    uint8_t index;
+
+    build_append_int_noprefix(table_data, 5, 1);  /* Type */
+    build_append_int_noprefix(table_data, 32, 1); /* Length */
+    build_append_int_noprefix(table_data, 0, 1);  /* Reserved */
+    build_append_int_noprefix(table_data, 1, 1);  /* Device Handle Type: PCI */
+    build_append_int_noprefix(table_data, node, 4);  /* Proximity Domain */
+
+    /* Device Handle - PCI */
+    build_append_int_noprefix(table_data, handle->segment, 2);
+    build_append_int_noprefix(table_data, handle->bdf, 2);
+    for (index = 0; index < 12; index++) {
+        build_append_int_noprefix(table_data, 0, 1);
+    }
+
+    build_append_int_noprefix(table_data, GEN_AFFINITY_ENABLED, 4); /* Flags */
+    build_append_int_noprefix(table_data, 0, 4);     /* Reserved */
+}
+
+static int build_all_acpi_generic_initiators(Object *obj, void *opaque)
+{
+    MachineState *ms = MACHINE(qdev_get_machine());
+    AcpiGenericInitiator *gi;
+    GArray *table_data = opaque;
+    PCIDeviceHandle dev_handle;
+    PCIDevice *pci_dev;
+    Object *o;
+
+    if (!object_dynamic_cast(obj, TYPE_ACPI_GENERIC_INITIATOR)) {
+        return 0;
+    }
+
+    gi = ACPI_GENERIC_INITIATOR(obj);
+    if (gi->node >= ms->numa_state->num_nodes) {
+        error_printf("%s: Specified node %d is invalid.\n",
+                     TYPE_ACPI_GENERIC_INITIATOR, gi->node);
+        exit(1);
+    }
+
+    o = object_resolve_path_type(gi->pci_dev, TYPE_PCI_DEVICE, NULL);
+    if (!o) {
+        error_printf("%s: Specified device must be a PCI device.\n",
+                     TYPE_ACPI_GENERIC_INITIATOR);
+        exit(1);
+    }
+
+    pci_dev = PCI_DEVICE(o);
+
+    dev_handle.segment = 0;
+    dev_handle.bdf = PCI_BUILD_BDF(pci_bus_num(pci_get_bus(pci_dev)),
+                                               pci_dev->devfn);
+
+    build_srat_generic_pci_initiator_affinity(table_data,
+                                              gi->node, &dev_handle);
+
+    return 0;
+}
+
+void build_srat_generic_pci_initiator(GArray *table_data)
+{
+    object_child_foreach_recursive(object_get_root(),
+                                   build_all_acpi_generic_initiators,
+                                   table_data);
+}

hw/acpi/hmat.c

@@ -214,7 +214,7 @@ static void hmat_build_table_structs(GArray *table_data, NumaState *numa_state)
     }
 
     for (i = 0; i < numa_state->num_nodes; i++) {
-        if (numa_state->nodes[i].has_cpu) {
+        if (numa_state->nodes[i].has_cpu || numa_state->nodes[i].has_gi) {
             initiator_list[num_initiator++] = i;
         }
     }

hw/arm/virt-acpi-build.c

@@ -57,6 +57,7 @@
 #include "migration/vmstate.h"
 #include "hw/acpi/ghes.h"
 #include "hw/acpi/viot.h"
+#include "hw/acpi/acpi_generic_initiator.h"
 #include "hw/virtio/virtio-acpi.h"
 #include "target/arm/multiprocessing.h"
 
@@ -504,6 +505,8 @@ build_srat(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
         }
     }
 
+    build_srat_generic_pci_initiator(table_data);
+
     if (ms->nvdimms_state->is_enabled) {
         nvdimm_build_srat(table_data);
     }

hw/core/numa.c

@@ -229,7 +229,8 @@ void parse_numa_hmat_lb(NumaState *numa_state, NumaHmatLBOptions *node,
                    node->target, numa_state->num_nodes);
         return;
     }
-    if (!numa_info[node->initiator].has_cpu) {
+    if (!numa_info[node->initiator].has_cpu &&
+        !numa_info[node->initiator].has_gi) {
         error_setg(errp, "Invalid initiator=%d, it isn't an "
                    "initiator proximity domain", node->initiator);
         return;

include/hw/acpi/acpi_generic_initiator.h

@@ -19,4 +19,29 @@ typedef struct AcpiGenericInitiator {
     uint16_t node;
 } AcpiGenericInitiator;
 
+/*
+ * ACPI 6.3:
+ * Table 5-81 Flags – Generic Initiator Affinity Structure
+ */
+typedef enum {
+    /*
+     * If clear, the OSPM ignores the contents of the Generic
+     * Initiator/Port Affinity Structure. This allows system firmware
+     * to populate the SRAT with a static number of structures, but only
+     * enable them as necessary.
+     */
+    GEN_AFFINITY_ENABLED = (1 << 0),
+} GenericAffinityFlags;
+
+/*
+ * ACPI 6.3:
+ * Table 5-80 Device Handle - PCI
+ */
+typedef struct PCIDeviceHandle {
+    uint16_t segment;
+    uint16_t bdf;
+} PCIDeviceHandle;
+
+void build_srat_generic_pci_initiator(GArray *table_data);
+
 #endif

include/sysemu/numa.h

@@ -41,6 +41,7 @@ struct NodeInfo {
     struct HostMemoryBackend *node_memdev;
     bool present;
     bool has_cpu;
+    bool has_gi;
     uint8_t lb_info_provided;
     uint16_t initiator;
     uint8_t distance[MAX_NODES];