[Qemu-devel] [PATCH v4 4/4] 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>:<slot>.<fn>

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

Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
---
 hw/ppc/spapr_pci.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 86 insertions(+), 12 deletions(-)

diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index 12f1b9c..d901007 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -769,6 +769,81 @@ static uint32_t spapr_phb_get_pci_drc_index(sPAPRPHBState *phb,
     return drck->get_index(drc);
 }
 
+static bool spapr_phb_vfio_get_devspec_value(PCIDevice *pdev, char **value)
+{
+    char *host;
+    char path[PATH_MAX];
+
+    host = object_property_get_str(OBJECT(pdev), "host", NULL);
+    if (!host) {
+        return false;
+    }
+
+    snprintf(path, sizeof(path), "/sys/bus/pci/devices/%s/devspec", host);
+    g_free(host);
+
+    return g_file_get_contents(path, value, NULL, NULL);
+}
+
+static char *spapr_phb_vfio_get_loc_code(sPAPRPHBState *sphb,  PCIDevice *pdev)
+{
+    char path[PATH_MAX], *buf = NULL;
+
+    /* We have a vfio host bridge lets get the path. */
+    if (!spapr_phb_vfio_get_devspec_value(pdev, &buf)) {
+        return NULL;
+    }
+
+    snprintf(path, sizeof(path), "/proc/device-tree%s/ibm,loc-code", buf);
+    g_free(buf);
+
+    g_file_get_contents(path, &buf, NULL, NULL);
+    return buf;
+}
+
+static char *spapr_phb_get_loc_code(sPAPRPHBState *sphb,  PCIDevice *pdev)
+{
+    char *path = g_malloc(PATH_MAX);
+
+    if (!path) {
+        return NULL;
+    }
+
+    /*
+     * For non-vfio devices make up the location code out
+     * of the name, slot and function.
+     *
+     *       qemu_<name>:<phb-index>:<slot>.<fn>
+     */
+    snprintf(path, PATH_MAX, "qemu_%s:%02d:%02d.%1d", pdev->name,
+             sphb->index, PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
+    return path;
+}
+
+
+static char *spapr_ibm_get_loc_code(sPAPRPHBState *sphb, PCIDevice *pdev)
+{
+    if (object_dynamic_cast(OBJECT(pdev), "vfio-pci") != NULL) {
+        char *buf = spapr_phb_vfio_get_loc_code(sphb, pdev);
+
+        /*
+         * In case of failures reading the loc-code, make it up
+         * indicating a vfio device
+         */
+        if (!buf) {
+            buf = g_malloc(PATH_MAX);
+            if (!buf) {
+                return NULL;
+            }
+            snprintf(buf, PATH_MAX, "vfio_%s:%02d:%02d.%1d", pdev->name,
+                     sphb->index, PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
+        }
+        return buf;
+    } else {
+        return spapr_phb_get_loc_code(sphb, pdev);
+    }
+}
+
 /* 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 */
@@ -906,12 +981,12 @@ static void populate_resource_props(PCIDevice *d, ResourceProps *rp)
 }
 
 static int spapr_populate_pci_child_dt(PCIDevice *dev, void *fdt, int offset,
-                                       sPAPRPHBState *sphb,
-                                       const char *drc_name)
+                                       sPAPRPHBState *sphb)
 {
     ResourceProps rp;
     bool is_bridge = false;
     int pci_status;
+    char *buf = NULL;
     uint32_t drc_index = spapr_phb_get_pci_drc_index(sphb, dev);
 
     if (pci_default_read_config(dev, PCI_HEADER_TYPE, 1) ==
@@ -973,9 +1048,10 @@ 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_ibm_get_loc_code(sphb, dev);
+    if (buf) {
+        _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));
@@ -1003,8 +1079,7 @@ typedef struct sPAPRFDT {
 } sPAPRFDT;
 
 /* create OF node for pci device and required OF DT properties */
-static int spapr_create_pci_child_dt(PCIDevice *pdev, sPAPRFDT *p,
-                                     const char *drc_name)
+static int spapr_create_pci_child_dt(PCIDevice *pdev, sPAPRFDT *p)
 {
     int offset, ret;
     char nodename[64];
@@ -1017,8 +1092,8 @@ static int spapr_create_pci_child_dt(PCIDevice *pdev, sPAPRFDT *p,
         sprintf(nodename, "pci@%d", slot);
     }
     offset = fdt_add_subnode(p->fdt, p->node_off, nodename);
-    ret = spapr_populate_pci_child_dt(pdev, p->fdt, offset, p->sphb,
-                                      drc_name);
+
+    ret = spapr_populate_pci_child_dt(pdev, p->fdt, offset, p->sphb);
     g_assert(!ret);
     if (ret) {
         return 0;
@@ -1033,7 +1108,6 @@ 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};
 
@@ -1041,7 +1115,7 @@ 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;
@@ -1519,7 +1593,7 @@ 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