From: Philippe Mathieu-Daudé <[email protected]>
We can trigger NMI from HMP or QMP.
QEMU maps the NMI to the s390x per-CPU 'RESTART' interrupt.
Linux guests usually setup this interrupt to trigger kdump
or crash. Such crashdump can be triggered in QEMU by HMP
"nmi" or QMP "inject-nmi" commands.
Using QMP, since we can not select a particular CPU, the first
CPU is used (CPU#0). See the documentation from commit 795dc6e4
("watchdog: Add new Virtual Watchdog action INJECT-NMI"):
@inject-nmi: a non-maskable interrupt is injected into the
first VCPU (all VCPUS on x86) (since 2.4)
While we can select a particular CPU on HMP, the guest behavior
is expected to be the same if using CPU #N or CPU #0. Since
always using CPU#0 simplifies API maintenance , update s390_nmi()
to inject NMI to the first CPU.
Signed-off-by: Philippe Mathieu-Daudé <[email protected]>
Reviewed-by: Peter Maydell <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
Signed-off-by: Philippe Mathieu-Daudé <[email protected]>
Reviewed-by: Eric Farman <[email protected]>
Reviewed-by: Marc-André Lureau <[email protected]>
---
qapi/machine.json | 7 ++++---
qapi/run-state.json | 6 ++++--
hw/s390x/s390-virtio-ccw.c | 4 +---
hmp-commands.hx | 5 +++--
4 files changed, 12 insertions(+), 10 deletions(-)
diff --git a/qapi/machine.json b/qapi/machine.json
index 9b2248038fc..2d63c1bac3b 100644
--- a/qapi/machine.json
+++ b/qapi/machine.json
@@ -432,9 +432,10 @@
##
# @inject-nmi:
#
-# Injects a Non-Maskable Interrupt into the default CPU (x86/s390) or
-# all CPUs (ppc64). The command fails when the guest doesn't support
-# injecting.
+# Injects a Non-Maskable Interrupt (machine specific: for example on
+# s390x CCW only the first vCPU receives the NMI, but on x86 machines
+# all vCPUs receive it). The command fails when the guest doesn't
+# support injecting.
#
# Since: 0.14
#
diff --git a/qapi/run-state.json b/qapi/run-state.json
index a5771ad4681..e4fdead1e0b 100644
--- a/qapi/run-state.json
+++ b/qapi/run-state.json
@@ -317,8 +317,10 @@
#
# @none: nothing is done
#
-# @inject-nmi: a non-maskable interrupt is injected into the first
-# VCPU (all VCPUS on x86) (since 2.4)
+# @inject-nmi: a non-maskable interrupt is injected (machine
+# specific: for example on s390x CCW only the first vCPU
+# receives the NMI, but on x86 machines all vCPUs receive
+# it). (since 2.4)
#
# Since: 2.1
##
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 25a9fa49554..4f7861dbbb7 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -727,9 +727,7 @@ static HotplugHandler
*s390_get_hotplug_handler(MachineState *machine,
static void s390_nmi(NMIState *n, int cpu_index, Error **errp)
{
- CPUState *cs = qemu_get_cpu(cpu_index);
-
- s390_cpu_restart(S390_CPU(cs));
+ s390_cpu_restart(S390_CPU(first_cpu));
}
static inline bool machine_get_aes_key_wrap(Object *obj, Error **errp)
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 7ae2468a3d9..a1b77ae4044 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -865,12 +865,13 @@ ERST
.name = "nmi",
.args_type = "",
.params = "",
- .help = "inject an NMI",
+ .help = "Inject an NMI, in a machine-specific way",
.cmd = hmp_nmi,
},
SRST
``nmi`` *cpu*
- Inject an NMI on the default CPU (x86/s390) or all CPUs (ppc64).
+ Inject an NMI, in a machine-specific way.
+ Not all machines implement NMI handling.
ERST
{
--
2.53.0
