On Friday 10 May 2019 12:07 PM, David Gibson wrote:
> On Wed, Apr 24, 2019 at 10:20:42AM +0530, Aravinda Prasad wrote:
> 65;5601;1c>
>>
>> On Tuesday 23 April 2019 12:23 PM, David Gibson wrote:
>>> On Mon, Apr 22, 2019 at 12:33:16PM +0530, Aravinda Prasad 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>
>>>
>>> LGTM, apart from one detail noted below.
>>>
>>>> ---
>>>> 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),
>>>
>>> So, technically this is a breaking change to the migration stream. If
>>> this is applied immediately after the earlier patch introducing the
>>> subsection it would be ok in practice, but it would still be
>>> preferable to make all the migration stream changes together.
>>
>> Do you mean that all .fields entries to vmstate_spapr_machine_check
>> should be in a single patch?
>
> Yes, that's preferable. If necessary you can move the migration
> support out into its own patch which goes after the implementation of
> the underlying state.
Sure..
>
>>
>> Because this patch introduced the variable mc_status, I added it to
>> vmstate_spapr_machine_check.
>>
>> Regards,
>> Aravinda
>>
>>>
>>>> VMSTATE_END_OF_LIST()
>>>> },
>>>> };
>>>> @@ -3085,6 +3087,7 @@ static void spapr_machine_init(MachineState *machine)
>>>> kvmppc_spapr_enable_inkernel_multitce();
>>>> }
>>>>
>>>> + spapr->mc_status = -1;
>>>> 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"
>>>> + */
>>>> + if (spapr->mc_status == cpu->vcpu_id) {
>>>> + qemu_system_guest_panicked(NULL);
>>>> + }
>>>> + 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"
>>>> +
>>>>
>>>
>>
>
--
Regards,
Aravinda
