target/ppc: Handle NMI guest exit
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 <arawinda.p@gmail.com>
Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
Message-Id: <20200130184423.20519-4-ganeshgr@linux.ibm.com>
[dwg: #ifdefs to fix compile for 32-bit target]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index aa739e9..06e295c 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1677,6 +1677,12 @@
first_ppc_cpu->env.gpr[5] = 0;
spapr->cas_reboot = false;
+
+ spapr->mc_status = -1;
+ spapr->guest_machine_check_addr = -1;
+
+ /* Signal all vCPUs waiting on this condition */
+ qemu_cond_broadcast(&spapr->mc_delivery_cond);
}
static void spapr_create_nvram(SpaprMachineState *spapr)
@@ -2971,6 +2977,8 @@
kvmppc_spapr_enable_inkernel_multitce();
}
+
+ qemu_cond_init(&spapr->mc_delivery_cond);
}
static int spapr_kvm_type(MachineState *machine, const char *vm_type)
diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
index e355e00..dfc0de8 100644
--- a/hw/ppc/spapr_events.c
+++ b/hw/ppc/spapr_events.c
@@ -40,6 +40,7 @@
#include "hw/ppc/spapr_drc.h"
#include "qemu/help_option.h"
#include "qemu/bcd.h"
+#include "qemu/main-loop.h"
#include "hw/ppc/spapr_ovec.h"
#include <libfdt.h>
@@ -622,6 +623,42 @@
RTAS_LOG_V6_HP_ACTION_REMOVE, drc_type, &drc_id);
}
+void spapr_mce_req_event(PowerPCCPU *cpu)
+{
+ SpaprMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
+ CPUState *cs = CPU(cpu);
+
+ if (spapr->guest_machine_check_addr == -1) {
+ /*
+ * This implies that we have hit a machine check either when the
+ * guest has not registered FWNMI (i.e., "ibm,nmi-register" not
+ * called) or between system reset and "ibm,nmi-register".
+ * Fall back to the old machine check behavior in such cases.
+ */
+ cs->exception_index = POWERPC_EXCP_MCHECK;
+ ppc_cpu_do_interrupt(cs);
+ return;
+ }
+
+ 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);
+ return;
+ }
+ 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/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 7bc5fc3..909d397 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -191,6 +191,15 @@
* occurs during the unplug process. */
QTAILQ_HEAD(, SpaprDimmState) pending_dimm_unplugs;
+ /* 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 >*/
char *kvm_type;
char *host_model;
@@ -804,6 +813,7 @@
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);
/* DRC callbacks. */
void spapr_core_release(DeviceState *dev);
diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index 4438d0c..56a6865 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -1705,6 +1705,13 @@
ret = 0;
break;
+#if defined(TARGET_PPC64)
+ case KVM_EXIT_NMI:
+ trace_kvm_handle_nmi_exception();
+ ret = kvm_handle_nmi(cpu, run);
+ break;
+#endif
+
default:
fprintf(stderr, "KVM: unknown exit reason %d\n", run->exit_reason);
ret = -1;
@@ -2800,6 +2807,17 @@
return data & 0xffff;
}
+#if defined(TARGET_PPC64)
+int kvm_handle_nmi(PowerPCCPU *cpu, struct kvm_run *run)
+{
+ cpu_synchronize_state(CPU(cpu));
+
+ spapr_mce_req_event(cpu);
+
+ return 0;
+}
+#endif
+
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 2c60ded..9e4f235 100644
--- a/target/ppc/kvm_ppc.h
+++ b/target/ppc/kvm_ppc.h
@@ -84,6 +84,8 @@
void kvmppc_set_reg_ppc_online(PowerPCCPU *cpu, unsigned int online);
void kvmppc_set_reg_tb_offset(PowerPCCPU *cpu, int64_t tb_offset);
+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 3dc6740..6d15aa9 100644
--- a/target/ppc/trace-events
+++ b/target/ppc/trace-events
@@ -28,3 +28,4 @@
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"
