[Qemu-devel] [PATCH v5] ppc: spapr-rtas - implement os-term rtas call

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

PAPR compliant guest calls this in absence of kdump. This finally
reaches the guest and can be handled according to the policies set by
higher level tools(like taking dump) for further analysis by tools like
crash.

Linux kernel calls ibm,os-term when extended property of os-term is set.
This makes sure that a return to the linux kernel is gauranteed.

CC: Benjamin Herrenschmidt <benh@au1.ibm.com>
CC: Anton Blanchard <anton@samba.org>
CC: Alexander Graf <agraf@suse.de>
CC: Tyrel Datwyler <turtle.in.the.kernel@gmail.com>
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>

---

v2: rebase to ppcnext
v3: Do not stop the VM, and update comments
v4: update spapr_register_rtas and qapi_event changes
v5: set ibm,extended-os-term as null encoded property
---
 hw/ppc/spapr.c         |  9 +++++++++
 hw/ppc/spapr_rtas.c    | 15 +++++++++++++++
 include/hw/ppc/spapr.h |  1 -
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 307c58d..e6c9014 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -520,6 +520,15 @@ static void *spapr_create_fdt_skel(hwaddr initrd_base,
 
     _FDT((fdt_property_cell(fdt, "rtas-error-log-max", RTAS_ERROR_LOG_MAX)));
 
+    /*
+     * According to PAPR, rtas ibm,os-term, does not gaurantee a return
+     * back to the guest cpu.
+     *
+     * While an additional ibm,extended-os-term property indicates that
+     * rtas call return will always occur. Set this property.
+     */
+    _FDT((fdt_property(fdt, "ibm,extended-os-term", NULL, 0)));
+
     _FDT((fdt_end_node(fdt)));
 
     /* interrupt controller */
diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index 9ba1ba6..2ec2a8e 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -277,6 +277,19 @@ static void rtas_ibm_set_system_parameter(PowerPCCPU *cpu,
     rtas_st(rets, 0, ret);
 }
 
+static void rtas_ibm_os_term(PowerPCCPU *cpu,
+                            sPAPREnvironment *spapr,
+                            uint32_t token, uint32_t nargs,
+                            target_ulong args,
+                            uint32_t nret, target_ulong rets)
+{
+    target_ulong ret = 0;
+
+    qapi_event_send_guest_panicked(GUEST_PANIC_ACTION_PAUSE, &error_abort);
+
+    rtas_st(rets, 0, ret);
+}
+
 static struct rtas_call {
     const char *name;
     spapr_rtas_fn fn;
@@ -404,6 +417,8 @@ static void core_rtas_register_types(void)
     spapr_rtas_register(RTAS_IBM_SET_SYSTEM_PARAMETER,
                         "ibm,set-system-parameter",
                         rtas_ibm_set_system_parameter);
+    spapr_rtas_register(RTAS_IBM_OS_TERM, "ibm,os-term",
+                        rtas_ibm_os_term);
 }
 
 type_init(core_rtas_register_types)
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index bbba51a..4e96381 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -382,7 +382,6 @@ int spapr_allocate_irq_block(int num, bool lsi, bool msi);
 #define RTAS_GET_SENSOR_STATE                   (RTAS_TOKEN_BASE + 0x1D)
 #define RTAS_IBM_CONFIGURE_CONNECTOR            (RTAS_TOKEN_BASE + 0x1E)
 #define RTAS_IBM_OS_TERM                        (RTAS_TOKEN_BASE + 0x1F)
-#define RTAS_IBM_EXTENDED_OS_TERM               (RTAS_TOKEN_BASE + 0x20)
 
 #define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x21)
 
-- 
1.8.3.1