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.
>
> 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"
> >> +
> >>
> >
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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