On Wed, Nov 26, 2025 at 03:49:53PM -0600, Praveen K Paladugu wrote: > When a root partition running on MSHV is powered off, the default > behavior is to write ACPI registers to power-off. However, this ACPI > write is intercepted by MSHV and will result in a Machine Check > Exception(MCE). > > The root partition eventually panics with a trace similar to: > > [ 81.306348] reboot: Power down > [ 81.314709] mce: [Hardware Error]: CPU 0: Machine Check Exception: 4 > Bank 0: b2000000c0060001 > [ 81.314711] mce: [Hardware Error]: TSC 3b8cb60a66 PPIN 11d98332458e4ea9 > [ 81.314713] mce: [Hardware Error]: PROCESSOR 0:606a6 TIME 1759339405 > SOCKET 0 APIC 0 microcode ffffffff > [ 81.314715] mce: [Hardware Error]: Run the above through 'mcelog --ascii' > [ 81.314716] mce: [Hardware Error]: Machine check: Processor context > corrupt > [ 81.314717] Kernel panic - not syncing: Fatal machine check > > To correctly shutdown a root partition running on MSHV hypervisor, sleep > state information must be configured within the hypervsior. Later, the > HVCALL_ENTER_SLEEP_STATE hypercall should be invoked as the last step in > the shutdown sequence. > > The previous patch configures the sleep state information and this patch > invokes HVCALL_ENTER_SLEEP_STATE hypercall to cleanly shutdown the root > partition. > > Signed-off-by: Praveen K Paladugu <[email protected]> > Co-developed-by: Anatol Belski <[email protected]> > Signed-off-by: Anatol Belski <[email protected]> > Reviewed-by: Easwar Hariharan <[email protected]> > --- > arch/x86/include/asm/mshyperv.h | 2 ++ > arch/x86/kernel/cpu/mshyperv.c | 2 ++ > drivers/hv/mshv_common.c | 18 ++++++++++++++++++ > 3 files changed, 22 insertions(+) > > diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h > index 166053df0484..4c22f3257368 100644 > --- a/arch/x86/include/asm/mshyperv.h > +++ b/arch/x86/include/asm/mshyperv.h > @@ -183,9 +183,11 @@ void hv_apic_init(void); > void __init hv_init_spinlocks(void); > bool hv_vcpu_is_preempted(int vcpu); > void hv_sleep_notifiers_register(void); > +void hv_machine_power_off(void); > #else > static inline void hv_apic_init(void) {} > static inline void hv_sleep_notifiers_register(void) {}; > +static inline void hv_machine_power_off(void) {}; > #endif > > struct irq_domain *hv_create_pci_msi_domain(void); > diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c > index fac9953a72ef..579fb2c64cfd 100644 > --- a/arch/x86/kernel/cpu/mshyperv.c > +++ b/arch/x86/kernel/cpu/mshyperv.c > @@ -621,6 +621,8 @@ static void __init ms_hyperv_init_platform(void) > #endif > > #if IS_ENABLED(CONFIG_HYPERV) > + if (hv_root_partition()) > + machine_ops.power_off = hv_machine_power_off; > #if defined(CONFIG_KEXEC_CORE) > machine_ops.shutdown = hv_machine_shutdown; > #endif > diff --git a/drivers/hv/mshv_common.c b/drivers/hv/mshv_common.c > index f1d4e81107ee..28905e3ed9c0 100644 > --- a/drivers/hv/mshv_common.c > +++ b/drivers/hv/mshv_common.c > @@ -217,4 +217,22 @@ void hv_sleep_notifiers_register(void) > pr_err("%s: cannot register reboot notifier %d\n", __func__, > ret); > } > + > +/* > + * Power off the machine by entering S5 sleep state via Hyper-V hypercall. > + * This call does not return if successful. > + */ > +void hv_machine_power_off(void) > +{ > + unsigned long flags; > + struct hv_input_enter_sleep_state *in; > + > + local_irq_save(flags); > + in = *this_cpu_ptr(hyperv_pcpu_input_arg); > + in->sleep_state = HV_SLEEP_STATE_S5; > + > + (void)hv_do_hypercall(HVCALL_ENTER_SLEEP_STATE, in, NULL);
Should this the error be printed? Acked-by: Stanislav Kinsburskii <[email protected]> > + local_irq_restore(flags); > + > +} > #endif > -- > 2.51.0
