On Friday 10 May 2019 09:55 PM, Greg Kurz wrote:
> On Mon, 22 Apr 2019 12:33:16 +0530
> Aravinda Prasad <aravi...@linux.vnet.ibm.com> wrote:
>
>> Memory error such as bit flips that cannot be corrected
>> by hardware are passed on to the kernel for handling.
>> If the memory address in error belongs to guest then
>> the guest kernel is responsible for taking suitable action.
>> Patch [1] enhances KVM to exit guest with exit reason
>> set to KVM_EXIT_NMI in such cases. This patch handles
>> KVM_EXIT_NMI exit.
>>
>> [1] https://www.spinics.net/lists/kvm-ppc/msg12637.html
>> (e20bbd3d and related commits)
>>
>> Signed-off-by: Aravinda Prasad <aravi...@linux.vnet.ibm.com>
>> ---
>> hw/ppc/spapr.c | 3 +++
>> hw/ppc/spapr_events.c | 22 ++++++++++++++++++++++
>> hw/ppc/spapr_rtas.c | 5 +++++
>> include/hw/ppc/spapr.h | 6 ++++++
>> target/ppc/kvm.c | 16 ++++++++++++++++
>> target/ppc/kvm_ppc.h | 2 ++
>> target/ppc/trace-events | 2 ++
>> 7 files changed, 56 insertions(+)
>>
>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>> index 6642cb5..2779efe 100644
>> --- a/hw/ppc/spapr.c
>> +++ b/hw/ppc/spapr.c
>> @@ -1806,6 +1806,7 @@ static void spapr_machine_reset(void)
>>
>> spapr->cas_reboot = false;
>>
>> + spapr->mc_status = -1;
>> spapr->guest_machine_check_addr = -1;
>>
>> /* Signal all vCPUs waiting on this condition */
>> @@ -2106,6 +2107,7 @@ static const VMStateDescription
>> vmstate_spapr_machine_check = {
>> .minimum_version_id = 1,
>> .fields = (VMStateField[]) {
>> VMSTATE_UINT64(guest_machine_check_addr, SpaprMachineState),
>> + VMSTATE_INT32(mc_status, SpaprMachineState),
>> VMSTATE_END_OF_LIST()
>> },
>> };
>> @@ -3085,6 +3087,7 @@ static void spapr_machine_init(MachineState *machine)
>> kvmppc_spapr_enable_inkernel_multitce();
>> }
>>
>> + spapr->mc_status = -1;
>
> Since this is done at reset, do we need it here ?
Yes, because we need to initialize this on a fresh boot. I need to
check, but if spapr_machine_reset() is called every time a system boots
then we don't need qemu_cond_init() here as well.
>
>> qemu_cond_init(&spapr->mc_delivery_cond);
>> }
>>
>> diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
>> index ae0f093..9922a23 100644
>> --- a/hw/ppc/spapr_events.c
>> +++ b/hw/ppc/spapr_events.c
>> @@ -620,6 +620,28 @@ void
>> spapr_hotplug_req_remove_by_count_indexed(SpaprDrcType drc_type,
>> RTAS_LOG_V6_HP_ACTION_REMOVE, drc_type,
>> &drc_id);
>> }
>>
>> +void spapr_mce_req_event(PowerPCCPU *cpu, bool recovered)
>> +{
>> + SpaprMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
>> +
>> + while (spapr->mc_status != -1) {
>> + /*
>> + * Check whether the same CPU got machine check error
>> + * while still handling the mc error (i.e., before
>> + * that CPU called "ibm,nmi-interlock"
>
> Missing )
ok.
>
>> + */
>> + if (spapr->mc_status == cpu->vcpu_id) {
>> + qemu_system_guest_panicked(NULL);
>
> If we don't also return, is there a chance we end up stuck in
> qemu_cond_wait_iothread() below ?
I think I need to return here
>
>> + }
>> + qemu_cond_wait_iothread(&spapr->mc_delivery_cond);
>> + /* Meanwhile if the system is reset, then just return */
>> + if (spapr->guest_machine_check_addr == -1) {
>> + return;
>> + }
>> + }
>> + spapr->mc_status = cpu->vcpu_id;
>> +}
>> +
>> static void check_exception(PowerPCCPU *cpu, SpaprMachineState *spapr,
>> uint32_t token, uint32_t nargs,
>> target_ulong args,
>> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
>> index c2f3991..d3499f9 100644
>> --- a/hw/ppc/spapr_rtas.c
>> +++ b/hw/ppc/spapr_rtas.c
>> @@ -375,6 +375,11 @@ static void rtas_ibm_nmi_interlock(PowerPCCPU *cpu,
>> /* NMI register not called */
>> rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
>> } else {
>> + /*
>> + * vCPU issuing "ibm,nmi-interlock" is done with NMI handling,
>> + * hence unset mc_status.
>> + */
>> + spapr->mc_status = -1;
>> qemu_cond_signal(&spapr->mc_delivery_cond);
>> rtas_st(rets, 0, RTAS_OUT_SUCCESS);
>> }
>> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
>> index ec6f33e..f7204d0 100644
>> --- a/include/hw/ppc/spapr.h
>> +++ b/include/hw/ppc/spapr.h
>> @@ -189,6 +189,11 @@ struct SpaprMachineState {
>>
>> /* State related to "ibm,nmi-register" and "ibm,nmi-interlock" calls */
>> target_ulong guest_machine_check_addr;
>> + /*
>> + * mc_status is set to -1 if mc is not in progress, else is set to the
>> CPU
>> + * handling the mc.
>> + */
>> + int mc_status;
>> QemuCond mc_delivery_cond;
>>
>> /*< public >*/
>> @@ -792,6 +797,7 @@ void spapr_clear_pending_events(SpaprMachineState
>> *spapr);
>> int spapr_max_server_number(SpaprMachineState *spapr);
>> void spapr_store_hpte(PowerPCCPU *cpu, hwaddr ptex,
>> uint64_t pte0, uint64_t pte1);
>> +void spapr_mce_req_event(PowerPCCPU *cpu, bool recovered);
>>
>> /* DRC callbacks. */
>> void spapr_core_release(DeviceState *dev);
>> diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
>> index 9e86db0..5eedce8 100644
>> --- a/target/ppc/kvm.c
>> +++ b/target/ppc/kvm.c
>> @@ -1759,6 +1759,11 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run
>> *run)
>> ret = 0;
>> break;
>>
>> + case KVM_EXIT_NMI:
>> + trace_kvm_handle_nmi_exception();
>> + ret = kvm_handle_nmi(cpu, run);
>> + break;
>> +
>> default:
>> fprintf(stderr, "KVM: unknown exit reason %d\n", run->exit_reason);
>> ret = -1;
>> @@ -2837,6 +2842,17 @@ int kvm_arch_msi_data_to_gsi(uint32_t data)
>> return data & 0xffff;
>> }
>>
>> +int kvm_handle_nmi(PowerPCCPU *cpu, struct kvm_run *run)
>> +{
>> + bool recovered = run->flags & KVM_RUN_PPC_NMI_DISP_FULLY_RECOV;
>> +
>> + cpu_synchronize_state(CPU(cpu));
>> +
>> + spapr_mce_req_event(cpu, recovered);
>> +
>> + return 0;
>> +}
>> +
>> int kvmppc_enable_hwrng(void)
>> {
>> if (!kvm_enabled() || !kvm_check_extension(kvm_state,
>> KVM_CAP_PPC_HWRNG)) {
>> diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h
>> index 2238513..6edc42f 100644
>> --- a/target/ppc/kvm_ppc.h
>> +++ b/target/ppc/kvm_ppc.h
>> @@ -80,6 +80,8 @@ bool kvmppc_hpt_needs_host_contiguous_pages(void);
>> void kvm_check_mmu(PowerPCCPU *cpu, Error **errp);
>> void kvmppc_set_reg_ppc_online(PowerPCCPU *cpu, unsigned int online);
>>
>> +int kvm_handle_nmi(PowerPCCPU *cpu, struct kvm_run *run);
>> +
>> #else
>>
>> static inline uint32_t kvmppc_get_tbfreq(void)
>> diff --git a/target/ppc/trace-events b/target/ppc/trace-events
>> index 7b3cfe1..d5691d2 100644
>> --- a/target/ppc/trace-events
>> +++ b/target/ppc/trace-events
>> @@ -28,3 +28,5 @@ kvm_handle_papr_hcall(void) "handle PAPR hypercall"
>> kvm_handle_epr(void) "handle epr"
>> kvm_handle_watchdog_expiry(void) "handle watchdog expiry"
>> kvm_handle_debug_exception(void) "handle debug exception"
>> +kvm_handle_nmi_exception(void) "handle NMI exception"
>> +
>
> new blank line at EOF.
ok
>
>>
>>
>
>
--
Regards,
Aravinda
