[Qemu-devel] [PATCH v6 5/6] spapr_pci: populate ibm,loc-code

[Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>]

Each hardware instance has a platform unique location code.  The OF
device tree that describes a part of a hardware entity must include
the “ibm,loc-code” property with a value that represents the location
code for that hardware entity.

Populate ibm,loc-code.

1) PCI passthru devices need to identify with its own ibm,loc-code
   available on the host. In failure cases use:
   vfio_<name>:<phb-index>:<bus>:<slot>.<fn>

2) Emulated devices encode as following:
   qemu_<name>:<phb-index>:<bus>:<slot>.<fn>

Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
---
 hw/ppc/spapr_pci.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 68 insertions(+), 10 deletions(-)

diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index 4226468..986bb21 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -746,6 +746,60 @@ static AddressSpace *spapr_pci_dma_iommu(PCIBus *bus, void *opaque, int devfn)
     return &phb->iommu_as;
 }
 
+static char *spapr_phb_vfio_get_loc_code(sPAPRPHBState *sphb,  PCIDevice *pdev)
+{
+    char *path = NULL, *buf = NULL, *host = NULL;
+
+    /* Get the PCI VFIO host id */
+    host = object_property_get_str(OBJECT(pdev), "host", NULL);
+    if (!host) {
+        goto err_out;
+    }
+
+    /* Construct the path of the file that will give us the DT location */
+    path = g_strdup_printf("/sys/bus/pci/devices/%s/devspec", host);
+    g_free(host);
+    if (!path || !g_file_get_contents(path, &buf, NULL, NULL)) {
+        goto err_out;
+    }
+    g_free(path);
+
+    /* Construct and read from host device tree the loc-code */
+    path = g_strdup_printf("/proc/device-tree%s/ibm,loc-code", buf);
+    g_free(buf);
+    if (!path || !g_file_get_contents(path, &buf, NULL, NULL)) {
+        goto err_out;
+    }
+    return buf;
+
+err_out:
+    g_free(path);
+    return NULL;
+}
+
+static char *spapr_phb_get_loc_code(sPAPRPHBState *sphb, PCIDevice *pdev)
+{
+    char *buf;
+    const char *devtype = "qemu";
+    uint32_t busnr = pci_bus_num(PCI_BUS(qdev_get_parent_bus(DEVICE(pdev))));
+
+    if (object_dynamic_cast(OBJECT(pdev), "vfio-pci")) {
+        buf = spapr_phb_vfio_get_loc_code(sphb, pdev);
+        if (buf) {
+            return buf;
+        }
+        devtype = "vfio";
+    }
+    /*
+     * For emulated devices and VFIO-failure case, make up
+     * the loc-code.
+     */
+    buf = g_strdup_printf("%s_%s:%04x:%02x:%02x.%x",
+                          devtype, pdev->name, sphb->index, busnr,
+                          PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
+    return buf;
+}
+
 /* Macros to operate with address in OF binding to PCI */
 #define b_x(x, p, l)    (((x) & ((1<<(l))-1)) << (p))
 #define b_n(x)          b_x((x), 31, 1) /* 0 if relocatable */
@@ -884,11 +938,12 @@ static void populate_resource_props(PCIDevice *d, ResourceProps *rp)
 
 static int spapr_populate_pci_child_dt(PCIDevice *dev, void *fdt, int offset,
                                        int phb_index, int drc_index,
-                                       const char *drc_name)
+                                       sPAPRPHBState *sphb)
 {
     ResourceProps rp;
     bool is_bridge = false;
     int pci_status;
+    char *buf = NULL;
 
     if (pci_default_read_config(dev, PCI_HEADER_TYPE, 1) ==
         PCI_HEADER_TYPE_BRIDGE) {
@@ -949,10 +1004,15 @@ static int spapr_populate_pci_child_dt(PCIDevice *dev, void *fdt, int offset,
      * processed by OF beforehand
      */
     _FDT(fdt_setprop_string(fdt, offset, "name", "pci"));
-    if (drc_name) {
-        _FDT(fdt_setprop(fdt, offset, "ibm,loc-code", drc_name,
-                         strlen(drc_name)));
+    buf = spapr_phb_get_loc_code(sphb, dev);
+    if (!buf) {
+        error_report("Failed setting the ibm,loc-code");
+        return -1;
     }
+
+    _FDT(fdt_setprop_string(fdt, offset, "ibm,loc-code", buf));
+    g_free(buf);
+
     if (drc_index) {
         _FDT(fdt_setprop_cell(fdt, offset, "ibm,my-drc-index", drc_index));
     }
@@ -982,8 +1042,7 @@ static uint32_t spapr_phb_get_pci_drc_index(sPAPRPHBState *phb,
                                             PCIDevice *pdev);
 
 /* create OF node for pci device and required OF DT properties */
-static int spapr_create_pci_child_dt(PCIDevice *dev, sPAPRFDT *p,
-                                     const char *drc_name)
+static int spapr_create_pci_child_dt(PCIDevice *dev, sPAPRFDT *p)
 {
     int offset, ret;
     int slot = PCI_SLOT(dev->devfn);
@@ -998,7 +1057,7 @@ static int spapr_create_pci_child_dt(PCIDevice *dev, sPAPRFDT *p,
     }
     offset = fdt_add_subnode(p->fdt, p->node_off, nodename);
     ret = spapr_populate_pci_child_dt(dev, p->fdt, offset, p->sphb->index,
-                                      drc_index, drc_name);
+                                      drc_index, p->sphb);
     g_assert(!ret);
     if (ret) {
         return 0;
@@ -1013,7 +1072,6 @@ static void spapr_phb_add_pci_device(sPAPRDRConnector *drc,
 {
     sPAPRDRConnectorClass *drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
     DeviceState *dev = DEVICE(pdev);
-    const char *drc_name = drck->get_name(drc);
     int fdt_start_offset = 0, fdt_size;
     sPAPRFDT s_fdt = {NULL, 0, NULL};
 
@@ -1021,7 +1079,7 @@ static void spapr_phb_add_pci_device(sPAPRDRConnector *drc,
         s_fdt.fdt = create_device_tree(&fdt_size);
         s_fdt.sphb = phb;
         s_fdt.node_off = 0;
-        fdt_start_offset = spapr_create_pci_child_dt(pdev, &s_fdt, drc_name);
+        fdt_start_offset = spapr_create_pci_child_dt(pdev, &s_fdt);
         if (!fdt_start_offset) {
             error_setg(errp, "Failed to create pci child device tree node");
             goto out;
@@ -1523,7 +1581,7 @@ static void spapr_populate_pci_devices_dt(PCIBus *bus, PCIDevice *pdev,
     int offset;
     sPAPRFDT s_fdt;
 
-    offset = spapr_create_pci_child_dt(pdev, p, NULL);
+    offset = spapr_create_pci_child_dt(pdev, p);
     if (!offset) {
         error_report("Failed to create pci child device tree node");
         return;
-- 
1.8.3.1