[Qemu-devel] [PATCH v6 5/6] ppc: spapr: Enable FWNMI capability

[Aravinda Prasad]

Enable the KVM capability KVM_CAP_PPC_FWNMI so that
the KVM causes guest exit with NMI as exit reason
when it encounters a machine check exception on the
address belonging to a guest. Without this capability
enabled, KVM redirects machine check exceptions to
guest's 0x200 vector.

Signed-off-by: Aravinda Prasad <aravi...@linux.vnet.ibm.com>
---
 hw/ppc/spapr_rtas.c  |   15 +++++++++++++++
 target/ppc/kvm.c     |   14 ++++++++++++++
 target/ppc/kvm_ppc.h |    6 ++++++
 3 files changed, 35 insertions(+)

diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index 0c2aa0d..aadd241 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -49,6 +49,7 @@
 #include "hw/ppc/fdt.h"
 #include "target/ppc/mmu-hash64.h"
 #include "target/ppc/mmu-book3s-v3.h"
+#include "kvm_ppc.h"
 
 static void rtas_display_character(PowerPCCPU *cpu, sPAPRMachineState *spapr,
                                    uint32_t token, uint32_t nargs,
@@ -354,6 +355,20 @@ static void rtas_ibm_nmi_register(PowerPCCPU *cpu,
                                   target_ulong args,
                                   uint32_t nret, target_ulong rets)
 {
+    int ret;
+
+    ret = kvmppc_fwnmi_enable(cpu);
+
+    if (ret == 1) {
+        rtas_st(rets, 0, RTAS_OUT_NOT_SUPPORTED);
+        return;
+    }
+
+    if (ret < 0) {
+        rtas_st(rets, 0, RTAS_OUT_HW_ERROR);
+        return;
+    }
+
     spapr->mc_reset = 0;
     spapr->guest_machine_check_addr = rtas_ld(args, 1);
     rtas_st(rets, 0, RTAS_OUT_SUCCESS);
diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index ba7738e..8786cec 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -91,6 +91,7 @@ static int cap_ppc_safe_cache;
 static int cap_ppc_safe_bounds_check;
 static int cap_ppc_safe_indirect_branch;
 static int cap_ppc_nested_kvm_hv;
+static int cap_ppc_fwnmi;
 
 static uint32_t debug_inst_opcode;
 
@@ -151,6 +152,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
     cap_resize_hpt = kvm_vm_check_extension(s, KVM_CAP_SPAPR_RESIZE_HPT);
     kvmppc_get_cpu_characteristics(s);
     cap_ppc_nested_kvm_hv = kvm_vm_check_extension(s, KVM_CAP_PPC_NESTED_HV);
+    cap_ppc_fwnmi = kvm_check_extension(s, KVM_CAP_PPC_FWNMI);
     /*
      * Note: setting it to false because there is not such capability
      * in KVM at this moment.
@@ -2049,6 +2051,18 @@ void kvmppc_set_mpic_proxy(PowerPCCPU *cpu, int 
mpic_proxy)
     }
 }
 
+int kvmppc_fwnmi_enable(PowerPCCPU *cpu)
+{
+    CPUState *cs = CPU(cpu);
+
+    if (!cap_ppc_fwnmi) {
+        return 1;
+    }
+
+    return kvm_vcpu_enable_cap(cs, KVM_CAP_PPC_FWNMI, 0);
+}
+
+
 int kvmppc_smt_threads(void)
 {
     return cap_ppc_smt ? cap_ppc_smt : 1;
diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h
index 0f40222..3645eb4 100644
--- a/target/ppc/kvm_ppc.h
+++ b/target/ppc/kvm_ppc.h
@@ -26,6 +26,7 @@ void kvmppc_enable_clear_ref_mod_hcalls(void);
 void kvmppc_set_papr(PowerPCCPU *cpu);
 int kvmppc_set_compat(PowerPCCPU *cpu, uint32_t compat_pvr);
 void kvmppc_set_mpic_proxy(PowerPCCPU *cpu, int mpic_proxy);
+int kvmppc_fwnmi_enable(PowerPCCPU *cpu);
 int kvmppc_smt_threads(void);
 void kvmppc_hint_smt_possible(Error **errp);
 int kvmppc_set_smt_threads(int smt);
@@ -150,6 +151,11 @@ static inline void kvmppc_set_mpic_proxy(PowerPCCPU *cpu, 
int mpic_proxy)
 {
 }
 
+int kvmppc_fwnmi_enable(PowerPCCPU *cpu)
+{
+    return 1;
+}
+
 static inline int kvmppc_smt_threads(void)
 {
     return 1;