| Message ID | 20240220150833.13674-3-philmd@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | hw/nmi: Remove @cpu_index argument | expand |
On Tue, 20 Feb 2024 at 15:09, Philippe Mathieu-Daudé <philmd@linaro.org> wrote: > > 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 maintainance, update s390_nmi() > to deliver NMI to the first CPU. > > Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org> > --- > qapi/run-state.json | 5 +++-- > hw/s390x/s390-virtio-ccw.c | 4 +--- > hmp-commands.hx | 2 +- > 3 files changed, 5 insertions(+), 6 deletions(-) > > diff --git a/qapi/run-state.json b/qapi/run-state.json > index 08bc99cb85..a2542f1a50 100644 > --- a/qapi/run-state.json > +++ b/qapi/run-state.json > @@ -320,8 +320,9 @@ > # > # @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 (architecture > +# specific: on s390x only the first vCPU receive the NMI, on "receives" > +# other architectures all vCPUs receive it). (since 2.4) This part isn't really true, because it's machine-specific rather than architecture-specific (and many architectures don't implement it at all). But I don't think we want to introduce that doc cleanup into this patch. Maybe we should leave it as only saying "all vCPUs on x86", though. > # > # Since: 2.1 > ## > diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c > index 62804cc228..ba1fa6472f 100644 > --- a/hw/s390x/s390-virtio-ccw.c > +++ b/hw/s390x/s390-virtio-ccw.c > @@ -605,9 +605,7 @@ 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 ram_addr_t s390_fixup_ram_size(ram_addr_t sz) > diff --git a/hmp-commands.hx b/hmp-commands.hx > index 17b5ea839d..2b01bb5926 100644 > --- a/hmp-commands.hx > +++ b/hmp-commands.hx > @@ -851,7 +851,7 @@ ERST > }, > SRST > ``nmi`` *cpu* > - Inject an NMI on the default CPU (x86/s390) or all CPUs (ppc64). > + Inject an NMI. > ERST > > { Reviewed-by: Peter Maydell <peter.maydell@linaro.org> thanks -- PMM
On 20.02.24 16:08, Philippe Mathieu-Daudé wrote: > 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 maintainance, update s390_nmi() > to deliver NMI to the first CPU. > > Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org> > --- Reviewed-by: David Hildenbrand <david@redhat.com>
diff --git a/qapi/run-state.json b/qapi/run-state.json index 08bc99cb85..a2542f1a50 100644 --- a/qapi/run-state.json +++ b/qapi/run-state.json @@ -320,8 +320,9 @@ # # @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 (architecture +# specific: on s390x only the first vCPU receive the NMI, on +# other architectures 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 62804cc228..ba1fa6472f 100644 --- a/hw/s390x/s390-virtio-ccw.c +++ b/hw/s390x/s390-virtio-ccw.c @@ -605,9 +605,7 @@ 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 ram_addr_t s390_fixup_ram_size(ram_addr_t sz) diff --git a/hmp-commands.hx b/hmp-commands.hx index 17b5ea839d..2b01bb5926 100644 --- a/hmp-commands.hx +++ b/hmp-commands.hx @@ -851,7 +851,7 @@ ERST }, SRST ``nmi`` *cpu* - Inject an NMI on the default CPU (x86/s390) or all CPUs (ppc64). + Inject an NMI. ERST {
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 maintainance, update s390_nmi() to deliver NMI to the first CPU. Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org> --- qapi/run-state.json | 5 +++-- hw/s390x/s390-virtio-ccw.c | 4 +--- hmp-commands.hx | 2 +- 3 files changed, 5 insertions(+), 6 deletions(-)