[Qemu-devel] [PATCH v5] spapr: add uuid/host details to device tree

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

Useful for identifying the guest/host uniquely within the
guest. Adding following properties to the guest root node.

vm,uuid - uuid of the guest
host-model - Host model number
host-serial - Host machine serial number
hypervisor type - Tells its "kvm"

Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>

---
v5:
   * Use glib function to read file
   * Callee allocates and caller frees
   * Remove "IBM," suffix
v4: make uuid as human readable
v3: rebase to ppcnext
v2: indentation fixes
---
 hw/ppc/spapr.c       | 28 ++++++++++++++++++++++++++++
 target-ppc/kvm.c     | 13 ++++++++++++-
 target-ppc/kvm_ppc.h | 12 ++++++++++++
 3 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 077ad2d..8c57ce4 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -318,6 +318,7 @@ static void *spapr_create_fdt_skel(hwaddr initrd_base,
     QemuOpts *opts = qemu_opts_find(qemu_find_opts("smp-opts"), NULL);
     unsigned sockets = opts ? qemu_opt_get_number(opts, "sockets", 0) : 0;
     uint32_t cpus_per_socket = sockets ? (smp_cpus / sockets) : 1;
+    char *buf;
 
     add_str(hypertas, "hcall-pft");
     add_str(hypertas, "hcall-term");
@@ -347,6 +348,33 @@ static void *spapr_create_fdt_skel(hwaddr initrd_base,
     _FDT((fdt_property_string(fdt, "model", "IBM pSeries (emulated by qemu)")));
     _FDT((fdt_property_string(fdt, "compatible", "qemu,pseries")));
 
+    if (kvm_enabled()) {
+        _FDT((fdt_property_string(fdt, "hypervisor", "kvm")));
+    }
+
+    /*
+     * Add info to guest to indentify which host is it being run on
+     * and what is the uuid of the guest
+     */
+    if (kvmppc_get_host_model(&buf)) {
+        _FDT((fdt_property_string(fdt, "host-model", buf)));
+        g_free(buf);
+    }
+    if (kvmppc_get_host_serial(&buf)) {
+        _FDT((fdt_property_string(fdt, "host-serial", buf)));
+        g_free(buf);
+    }
+
+    buf = g_strdup_printf(UUID_FMT, qemu_uuid[0], qemu_uuid[1],
+                          qemu_uuid[2], qemu_uuid[3], qemu_uuid[4],
+                          qemu_uuid[5], qemu_uuid[6], qemu_uuid[7],
+                          qemu_uuid[8], qemu_uuid[9], qemu_uuid[10],
+                          qemu_uuid[11], qemu_uuid[12], qemu_uuid[13],
+                          qemu_uuid[14], qemu_uuid[15]);
+
+    _FDT((fdt_property_string(fdt, "vm,uuid", buf)));
+    g_free(buf);
+
     _FDT((fdt_property_cell(fdt, "#address-cells", 0x2)));
     _FDT((fdt_property_cell(fdt, "#size-cells", 0x2)));
 
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index 2d87108..afc7963 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -1369,7 +1369,7 @@ static int read_cpuinfo(const char *field, char *value, int len)
     }
 
     do {
-        if(!fgets(line, sizeof(line), f)) {
+        if (!fgets(line, sizeof(line), f)) {
             break;
         }
         if (!strncmp(line, field, field_len)) {
@@ -1404,6 +1404,17 @@ uint32_t kvmppc_get_tbfreq(void)
     return retval;
 }
 
+bool kvmppc_get_host_serial(char **value)
+{
+    return g_file_get_contents("/proc/device-tree/system-id", value, NULL,
+                               NULL);
+}
+
+bool kvmppc_get_host_model(char **value)
+{
+    return g_file_get_contents("/proc/device-tree/model", value, NULL, NULL);
+}
+
 /* Try to find a device tree node for a CPU with clock-frequency property */
 static int kvmppc_find_cpu_dt(char *buf, int buf_len)
 {
diff --git a/target-ppc/kvm_ppc.h b/target-ppc/kvm_ppc.h
index 1118122..fad2b8c 100644
--- a/target-ppc/kvm_ppc.h
+++ b/target-ppc/kvm_ppc.h
@@ -19,6 +19,8 @@ uint32_t kvmppc_get_tbfreq(void);
 uint64_t kvmppc_get_clockfreq(void);
 uint32_t kvmppc_get_vmx(void);
 uint32_t kvmppc_get_dfp(void);
+bool kvmppc_get_host_model(char **buf);
+bool kvmppc_get_host_serial(char **buf);
 int kvmppc_get_hasidle(CPUPPCState *env);
 int kvmppc_get_hypercall(CPUPPCState *env, uint8_t *buf, int buf_len);
 int kvmppc_set_interrupt(PowerPCCPU *cpu, int irq, int level);
@@ -60,6 +62,16 @@ static inline uint32_t kvmppc_get_tbfreq(void)
     return 0;
 }
 
+static inline bool kvmppc_get_host_model(char **buf)
+{
+    return false;
+}
+
+static inline bool kvmppc_get_host_serial(char **buf)
+{
+    return false;
+}
+
 static inline uint64_t kvmppc_get_clockfreq(void)
 {
     return 0;
-- 
1.8.3.1