| Message ID | 20171120100347.8601-3-clg@kaod.org |
|---|---|
| State | New |
| Headers | show |
| Series | disable the decrementer interrupt when a CPU is unplugged | expand |
On Mon, Nov 20, 2017 at 11:03:46AM +0100, Cédric Le Goater wrote: > Just like for hot unplug CPUs, when a guest is rebooted, the secondary > CPUs can be awaken by the decrementer and start entering SLOF at the > same time the boot CPU is. > > To be safe, let's disable on the secondaries all the exceptions which > can cause an exit while the CPU is in power-saving mode. > > Based on previous work from Nikunj A Dadhania <nikunj@linux.vnet.ibm.com> > > Signed-off-by: Cédric Le Goater <clg@kaod.org> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> but not applying pending an update on 1/3. > --- > > Changes in v3: > > - used the cpu_ppc_papr_pece_bits() helper > > hw/ppc/spapr_cpu_core.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c > index 3a4c17401226..4ba8563d49e4 100644 > --- a/hw/ppc/spapr_cpu_core.c > +++ b/hw/ppc/spapr_cpu_core.c > @@ -35,6 +35,13 @@ static void spapr_cpu_reset(void *opaque) > cs->halted = 1; > > env->spr[SPR_HIOR] = 0; > + > + /* Disable Power-saving mode Exit Cause exceptions for the CPU. > + * This can cause issues when rebooting the guest if a secondary > + * is awaken */ > + if (cs != first_cpu) { > + env->spr[SPR_LPCR] &= ~cpu_ppc_papr_pece_bits(env); > + } > } > > static void spapr_cpu_destroy(PowerPCCPU *cpu)
diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c index 3a4c17401226..4ba8563d49e4 100644 --- a/hw/ppc/spapr_cpu_core.c +++ b/hw/ppc/spapr_cpu_core.c @@ -35,6 +35,13 @@ static void spapr_cpu_reset(void *opaque) cs->halted = 1; env->spr[SPR_HIOR] = 0; + + /* Disable Power-saving mode Exit Cause exceptions for the CPU. + * This can cause issues when rebooting the guest if a secondary + * is awaken */ + if (cs != first_cpu) { + env->spr[SPR_LPCR] &= ~cpu_ppc_papr_pece_bits(env); + } } static void spapr_cpu_destroy(PowerPCCPU *cpu)
Just like for hot unplug CPUs, when a guest is rebooted, the secondary CPUs can be awaken by the decrementer and start entering SLOF at the same time the boot CPU is. To be safe, let's disable on the secondaries all the exceptions which can cause an exit while the CPU is in power-saving mode. Based on previous work from Nikunj A Dadhania <nikunj@linux.vnet.ibm.com> Signed-off-by: Cédric Le Goater <clg@kaod.org> --- Changes in v3: - used the cpu_ppc_papr_pece_bits() helper hw/ppc/spapr_cpu_core.c | 7 +++++++ 1 file changed, 7 insertions(+)