[Qemu-devel] [PATCH 2/2] spapr: 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.

Introduce an hcall to populate ibm,loc-cde.
1) PCI passthru devices need to identify with its own ibm,loc-code
   available on the host.
2) Emulated devices encode as following: qemu_<name>:<slot>.<fn>

Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
---
 hw/ppc/spapr_hcall.c          | 10 +++++++++
 hw/ppc/spapr_pci.c            | 49 +++++++++++++++++++++++++++++++++++++++++++
 hw/vfio/pci.c                 | 18 ++++++++++++++++
 include/hw/ppc/spapr.h        |  8 ++++++-
 include/hw/vfio/vfio-common.h |  1 +
 5 files changed, 85 insertions(+), 1 deletion(-)

diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
index 4f76f1c..a577395 100644
--- a/hw/ppc/spapr_hcall.c
+++ b/hw/ppc/spapr_hcall.c
@@ -928,6 +928,15 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu_,
     return H_SUCCESS;
 }
 
+static target_ulong h_get_loc_code(PowerPCCPU *cpu, sPAPREnvironment *spapr,
+				   target_ulong opcode, target_ulong *args)
+{
+    if (!spapr_h_get_loc_code(spapr, args[0], args[1], args[2], args[3])) {
+        return H_PARAMETER;
+    }
+    return H_SUCCESS;
+}
+
 static spapr_hcall_fn papr_hypercall_table[(MAX_HCALL_OPCODE / 4) + 1];
 static spapr_hcall_fn kvmppc_hypercall_table[KVMPPC_HCALL_MAX - KVMPPC_HCALL_BASE + 1];
 
@@ -1010,6 +1019,7 @@ static void hypercall_register_types(void)
 
     /* ibm,client-architecture-support support */
     spapr_register_hypercall(KVMPPC_H_CAS, h_client_architecture_support);
+    spapr_register_hypercall(KVMPPC_H_GET_LOC_CODE, h_get_loc_code);
 }
 
 type_init(hypercall_register_types)
diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index 05f4fac..65cdb91 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -35,6 +35,7 @@
 #include "qemu/error-report.h"
 
 #include "hw/pci/pci_bus.h"
+#include "hw/vfio/vfio-common.h"
 
 /* Copied from the kernel arch/powerpc/platforms/pseries/msi.c */
 #define RTAS_QUERY_FN           0
@@ -248,6 +249,54 @@ static void spapr_msi_setmsg(PCIDevice *pdev, hwaddr addr, bool msix,
     }
 }
 
+bool spapr_h_get_loc_code(sPAPREnvironment *spapr, target_ulong config_addr, target_ulong buid,
+                          target_ulong loc_code, target_ulong size)
+{
+    sPAPRPHBState *sphb = NULL;
+    PCIDevice *pdev = NULL;
+    char *buf, path[PATH_MAX];
+    struct stat st;
+
+    sphb = find_phb(spapr, buid);
+    if (sphb) {
+        pdev = find_dev(spapr, buid, config_addr);
+    }
+
+    if (!sphb || !pdev) {
+        error_report("spapr_h_get_loc_code: Device not found");
+        return false;
+    }
+
+    /* For a VFIO device, get the location in the device tree */
+    if (pdev->is_vfio && vfio_get_devspec(pdev, &buf)) {
+        snprintf(path, sizeof(path), "/proc/device-tree%s/ibm,loc-code", buf);
+        g_free(buf);
+        if (stat(path, &st) < 0) {
+            goto fail;
+        }
+
+        /* A valid file, now read the loc-code */
+        if (g_file_get_contents(path, &buf, NULL, NULL)) {
+            cpu_physical_memory_write(loc_code, buf, strlen(buf));
+            g_free(buf);
+            goto out;
+        }
+    }
+
+fail:
+    /*
+     * For non-vfio devices and failure cases, make up the location
+     * code out of the name, slot and function.
+     *
+     *       qemu_<name>:<slot>.<fn>
+     */
+    snprintf(path, sizeof(path), "qemu_%s:%02d.%1d", pdev->name,
+             PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
+    cpu_physical_memory_write(loc_code, path, size);
+ out:
+    return true;
+}
+
 static void rtas_ibm_change_msi(PowerPCCPU *cpu, sPAPREnvironment *spapr,
                                 uint32_t token, uint32_t nargs,
                                 target_ulong args, uint32_t nret,
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 95d666e..dd97258 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3319,6 +3319,24 @@ static void vfio_unregister_req_notifier(VFIOPCIDevice *vdev)
     vdev->req_enabled = false;
 }
 
+bool vfio_get_devspec(PCIDevice *pdev, char **value)
+{
+    VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
+    char path[PATH_MAX];
+    struct stat st;
+
+    snprintf(path, sizeof(path),
+             "/sys/bus/pci/devices/%04x:%02x:%02x.%01x/devspec",
+             vdev->host.domain, vdev->host.bus, vdev->host.slot,
+             vdev->host.function);
+
+    if (stat(path, &st) < 0) {
+        return false;
+    }
+
+    return g_file_get_contents(path, value, NULL, NULL);
+}
+
 static int vfio_initfn(PCIDevice *pdev)
 {
     VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index af71e8b..d3fad67 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -310,7 +310,10 @@ typedef struct sPAPREnvironment {
 #define KVMPPC_H_LOGICAL_MEMOP  (KVMPPC_HCALL_BASE + 0x1)
 /* Client Architecture support */
 #define KVMPPC_H_CAS            (KVMPPC_HCALL_BASE + 0x2)
-#define KVMPPC_HCALL_MAX        KVMPPC_H_CAS
+#define KVMPPC_H_RTAS_UPDATE    (KVMPPC_HCALL_BASE + 0x3)
+#define KVMPPC_H_REPORT_MC_ERR  (KVMPPC_HCALL_BASE + 0x4)
+#define KVMPPC_H_GET_LOC_CODE   (KVMPPC_HCALL_BASE + 0x5)
+#define KVMPPC_HCALL_MAX        KVMPPC_H_GET_LOC_CODE
 
 extern sPAPREnvironment *spapr;
 
@@ -522,6 +525,9 @@ int spapr_tcet_dma_dt(void *fdt, int node_off, const char *propname,
                       sPAPRTCETable *tcet);
 void spapr_pci_switch_vga(bool big_endian);
 
+bool spapr_h_get_loc_code(sPAPREnvironment *spapr, target_ulong config_addr, target_ulong build,
+			  target_ulong loc_code, target_ulong size);
+
 #define TYPE_SPAPR_RTC "spapr-rtc"
 
 void spapr_rtc_read(DeviceState *dev, struct tm *tm, uint32_t *ns);
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 0d1fb80..6dffa8c 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -140,6 +140,7 @@ VFIOGroup *vfio_get_group(int groupid, AddressSpace *as);
 void vfio_put_group(VFIOGroup *group);
 int vfio_get_device(VFIOGroup *group, const char *name,
                     VFIODevice *vbasedev);
+bool vfio_get_devspec(PCIDevice *pdev, char **value);
 
 extern const MemoryRegionOps vfio_region_ops;
 extern QLIST_HEAD(vfio_group_head, VFIOGroup) vfio_group_list;
-- 
1.8.3.1