[Qemu-ppc] [PATCH v7 2/2] spapr-rtas: add ibm, get-vpd RTAS interface

[Maxiwell S. Garcia]

This adds a handler for ibm,get-vpd RTAS calls, allowing pseries guest
to collect host information. It is disabled by default to avoid unwanted
information leakage. To enable it, use:

-M pseries,host-serial={passthrough|string},host-model={passthrough|string}

Only the SE and TM keywords are returned at the moment.
SE for Machine or Cabinet Serial Number and
TM for Machine Type and Model

The SE and TM keywords are controlled by 'host-serial' and 'host-model'
options, respectively. In the case of 'passthrough', the SE shows the
host 'system-id' information and the TM shows the host 'model' information.

Powerpc-utils tools can dispatch RTAS calls to retrieve host
information using this ibm,get-vpd interface. The 'host-serial'
and 'host-model' nodes of device-tree hold the same information but
in a static manner, which is useless after a migration operation.

Signed-off-by: Maxiwell S. Garcia <address@hidden>
---
 hw/ppc/spapr_rtas.c    | 96 ++++++++++++++++++++++++++++++++++++++++++
 include/hw/ppc/spapr.h | 10 ++++-
 2 files changed, 105 insertions(+), 1 deletion(-)

diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index 24c45b12d4..c42630e95d 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -287,6 +287,98 @@ static void rtas_ibm_set_system_parameter(PowerPCCPU *cpu,
     rtas_st(rets, 0, ret);
 }
 
+static int vpd_st(target_ulong addr, target_ulong len,
+                  const void *val, uint16_t val_len)
+{
+    hwaddr phys = ppc64_phys_to_real(addr);
+
+    if (len < val_len) {
+        return RTAS_OUT_PARAM_ERROR;
+    }
+
+    cpu_physical_memory_write(phys, val, val_len);
+    return RTAS_OUT_SUCCESS;
+}
+
+static void vpd_ret(target_ulong rets, const int status,
+                    const int next_seq_number, const int bytes_returned)
+{
+    rtas_st(rets, 0, status);
+    rtas_st(rets, 1, next_seq_number);
+    rtas_st(rets, 2, bytes_returned);
+}
+
+static void rtas_ibm_get_vpd_fields_register(SpaprMachineState *spapr)
+{
+    int i = 0;
+    char *buf = NULL;
+
+    memset(spapr->rtas_get_vpd_fields, 0,
+           sizeof(spapr->rtas_get_vpd_fields));
+
+    buf = spapr_get_valid_host_serial(spapr);
+    if (buf) {
+        spapr->rtas_get_vpd_fields[i++] = g_strdup_printf("SE %s", buf);
+        g_free(buf);
+    }
+
+    buf = spapr_get_valid_host_model(spapr);
+    if (buf) {
+        spapr->rtas_get_vpd_fields[i++] = g_strdup_printf("TM %s", buf);
+        g_free(buf);
+    }
+}
+
+static void rtas_ibm_get_vpd(PowerPCCPU *cpu,
+                             SpaprMachineState *spapr,
+                             uint32_t token, uint32_t nargs,
+                             target_ulong args,
+                             uint32_t nret, target_ulong rets)
+{
+    target_ulong loc_code_addr = rtas_ld(args, 0);
+    target_ulong work_area_addr = rtas_ld(args, 1);
+    target_ulong work_area_size = rtas_ld(args, 2);
+    target_ulong seq_number = rtas_ld(args, 3);
+    unsigned int next_seq_number = 1;
+    int status = RTAS_OUT_PARAM_ERROR;
+    unsigned char loc_code;
+    unsigned int vpd_field_len;
+    char *vpd_field;
+    int ret;
+
+    /* Specific Location Code is not supported and seq_number */
+    /* must be checked to avoid out of bound index error */
+    cpu_physical_memory_read(loc_code_addr, &loc_code, 1);
+    if ((loc_code != 0) || (seq_number <= 0) ||
+        (seq_number > RTAS_IBM_GET_VPD_MAX)) {
+        vpd_ret(rets, RTAS_OUT_PARAM_ERROR, 1, 0);
+        return;
+    }
+
+    /* RTAS not authorized if no keywords have been registered */
+    if (!spapr->rtas_get_vpd_fields[seq_number - 1]) {
+        vpd_ret(rets, RTAS_OUT_NOT_AUTHORIZED, 1, 0);
+        return;
+    }
+
+    vpd_field = spapr->rtas_get_vpd_fields[seq_number - 1];
+    vpd_field_len = strlen(vpd_field);
+    ret = vpd_st(work_area_addr, work_area_size,
+                 vpd_field, vpd_field_len + 1);
+
+    if (ret == 0) {
+        next_seq_number = seq_number + 1;
+        if (spapr->rtas_get_vpd_fields[next_seq_number - 1]) {
+            status = RTAS_IBM_GET_VPD_CONTINUE;
+        } else {
+            status = RTAS_OUT_SUCCESS;
+            next_seq_number = 1;
+        }
+    }
+
+    vpd_ret(ret, status, next_seq_number, vpd_field_len);
+}
+
 static void rtas_ibm_os_term(PowerPCCPU *cpu,
                             SpaprMachineState *spapr,
                             uint32_t token, uint32_t nargs,
@@ -464,6 +556,8 @@ void spapr_load_rtas(SpaprMachineState *spapr, void *fdt, 
hwaddr addr)
                      fdt_strerror(ret));
         exit(1);
     }
+
+    rtas_ibm_get_vpd_fields_register(spapr);
 }
 
 static void core_rtas_register_types(void)
@@ -485,6 +579,8 @@ static void core_rtas_register_types(void)
                         rtas_ibm_set_system_parameter);
     spapr_rtas_register(RTAS_IBM_OS_TERM, "ibm,os-term",
                         rtas_ibm_os_term);
+    spapr_rtas_register(RTAS_IBM_GET_VPD, "ibm,get-vpd",
+                        rtas_ibm_get_vpd);
     spapr_rtas_register(RTAS_SET_POWER_LEVEL, "set-power-level",
                         rtas_set_power_level);
     spapr_rtas_register(RTAS_GET_POWER_LEVEL, "get-power-level",
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 5e0a1b2a8a..d2e9f48057 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -99,6 +99,9 @@ typedef enum {
 #define SPAPR_CAP_FIXED_CCD             0x03
 #define SPAPR_CAP_FIXED_NA              0x10 /* Lets leave a bit of a gap... */
 
+/* Maximum number of ibm,get-vpd fields supported */
+#define RTAS_IBM_GET_VPD_MAX 2
+
 typedef struct SpaprCapabilities SpaprCapabilities;
 struct SpaprCapabilities {
     uint8_t caps[SPAPR_CAP_NUM];
@@ -167,6 +170,7 @@ struct SpaprMachineState {
     QTAILQ_HEAD(, SpaprEventLogEntry) pending_events;
     bool use_hotplug_event_source;
     SpaprEventSource *event_sources;
+    char *rtas_get_vpd_fields[RTAS_IBM_GET_VPD_MAX + 1];
 
     /* ibm,client-architecture-support option negotiation */
     bool cas_reboot;
@@ -619,14 +623,18 @@ target_ulong spapr_hypercall(PowerPCCPU *cpu, 
target_ulong opcode,
 #define RTAS_IBM_CREATE_PE_DMA_WINDOW           (RTAS_TOKEN_BASE + 0x27)
 #define RTAS_IBM_REMOVE_PE_DMA_WINDOW           (RTAS_TOKEN_BASE + 0x28)
 #define RTAS_IBM_RESET_PE_DMA_WINDOW            (RTAS_TOKEN_BASE + 0x29)
+#define RTAS_IBM_GET_VPD                        (RTAS_TOKEN_BASE + 0x2A)
 
-#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2A)
+#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2B)
 
 /* RTAS ibm,get-system-parameter token values */
 #define RTAS_SYSPARM_SPLPAR_CHARACTERISTICS      20
 #define RTAS_SYSPARM_DIAGNOSTICS_RUN_MODE        42
 #define RTAS_SYSPARM_UUID                        48
 
+/* RTAS ibm,get-vpd status value */
+#define RTAS_IBM_GET_VPD_CONTINUE 1
+
 /* RTAS indicator/sensor types
  *
  * as defined by PAPR+ 2.7 7.3.5.4, Table 41
-- 
2.20.1