[PATCH v5 3/6] ppc/spapr: Add support for ibm, open-errinjct and ibm, close-errinjct

[Narayana Murty N <nnmlinux@linux.ibm.com>]

Add RTAS handlers for ibm,open-errinjct and ibm,close-errinjct.  These
calls manage exclusive access to the error-injection facility through a
simple session token mechanism: only one session may be open at a time.

ibm,open-errinjct (nargs=0, nret=2):
  Returns rets[0]=token, rets[1]=status.
  On success: token=1, status=RTAS_OUT_SUCCESS.
  Already-open: token=0, status=RTAS_OUT_ALREADY_OPEN.
  Bad args:    token=0, status=RTAS_OUT_PARAM_ERROR.

ibm,close-errinjct (nargs=1, nret=1):
  Takes the session token in args[0].
  Returns RTAS_OUT_SUCCESS on a matching open token.
  Returns RTAS_OUT_NOT_OPEN if the token is invalid or no session exists.

RTAS_IBM_OPEN_ERRINJCT and RTAS_IBM_CLOSE_ERRINJCT token values and
RTAS_OUT_ALREADY_OPEN / RTAS_OUT_NOT_OPEN return codes are added to
include/hw/ppc/spapr.h.

Signed-off-by: Narayana Murty N <nnmlinux@linux.ibm.com>
---
 include/hw/ppc/spapr.h |  8 +++++-
 hw/ppc/spapr_pci.c     | 57 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 47791c71bd..bcb1da5fab 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -825,8 +825,14 @@ enum rtas_err_type {
 #define RTAS_IBM_NMI_INTERLOCK                  (RTAS_TOKEN_BASE + 0x2C)
 #define RTAS_CONFIGURE_KERNEL_DUMP              (RTAS_TOKEN_BASE + 0x2D)
 #define RTAS_IBM_ERRINJCT                       (RTAS_TOKEN_BASE + 0x2E)
+#define RTAS_IBM_OPEN_ERRINJCT                  (RTAS_TOKEN_BASE + 0x2F)
+#define RTAS_IBM_CLOSE_ERRINJCT                 (RTAS_TOKEN_BASE + 0x30)
 
-#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2F)
+#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x31)
+
+/* ibm,open-errinjct/ibm,close-errinjct return codes */
+#define RTAS_OUT_ALREADY_OPEN                   -4
+#define RTAS_OUT_NOT_OPEN                       -5
 
 /* RTAS ibm,get-system-parameter token values */
 #define RTAS_SYSPARM_SPLPAR_CHARACTERISTICS      20
diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index cff12ef268..20cb913f12 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -836,6 +836,57 @@ param_error_exit:
     rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
 }
 
+static void rtas_ibm_open_errinjct(PowerPCCPU *cpu, SpaprMachineState *spapr,
+                                   uint32_t token, uint32_t nargs,
+                                   target_ulong args, uint32_t nret,
+                                   target_ulong rets)
+{
+    if (nargs != 0 || nret != 2) {
+        rtas_st(rets, 0, 0);
+        rtas_st(rets, 1, RTAS_OUT_PARAM_ERROR);
+        return;
+    }
+
+    if (spapr->errinjct_token) {
+        /* Session already open: return token=0, status=ALREADY_OPEN */
+        rtas_st(rets, 0, 0);
+        rtas_st(rets, 1, RTAS_OUT_ALREADY_OPEN);
+        return;
+    }
+
+    spapr->errinjct_token = 1;
+
+    /*
+     * ibm,open-errinjct has an unusual return convention: rets[0] is the
+     * session token and rets[1] is the status code.
+     */
+    rtas_st(rets, 0, spapr->errinjct_token);
+    rtas_st(rets, 1, RTAS_OUT_SUCCESS);
+}
+
+static void rtas_ibm_close_errinjct(PowerPCCPU *cpu, SpaprMachineState *spapr,
+                                    uint32_t token, uint32_t nargs,
+                                    target_ulong args, uint32_t nret,
+                                    target_ulong rets)
+{
+    uint32_t o_token;
+
+    if (nargs != 1 || nret != 1) {
+        rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
+        return;
+    }
+
+    o_token = rtas_ld(args, 0);
+
+    if (!spapr->errinjct_token || o_token != spapr->errinjct_token) {
+        rtas_st(rets, 0, RTAS_OUT_NOT_OPEN);
+        return;
+    }
+
+    spapr->errinjct_token = 0;
+    rtas_st(rets, 0, RTAS_OUT_SUCCESS);
+}
+
 static void pci_spapr_set_irq(void *opaque, int irq_num, int level)
 {
     /*
@@ -2515,6 +2566,12 @@ void spapr_pci_rtas_init(void)
     spapr_rtas_register(RTAS_IBM_ERRINJCT,
                         "ibm,errinjct",
                         rtas_ibm_errinjct);
+    spapr_rtas_register(RTAS_IBM_OPEN_ERRINJCT,
+                        "ibm,open-errinjct",
+                        rtas_ibm_open_errinjct);
+    spapr_rtas_register(RTAS_IBM_CLOSE_ERRINJCT,
+                        "ibm,close-errinjct",
+                        rtas_ibm_close_errinjct);
 }
 
 static void spapr_pci_register_types(void)
-- 
2.51.1