[RFC PATCH 04/13] ppc/spapr: Disable FWNMI capability if KVM does not support it

[Nicholas Piggin]

This is a fatal error if KVM does not support this capability, so try to
disable it if that's the case.

Signed-off-by: Nicholas Piggin <address@hidden>
---
 hw/ppc/spapr_caps.c  | 7 ++++++-
 target/ppc/kvm.c     | 7 +++++++
 target/ppc/kvm_ppc.h | 6 ++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
index 10864c7eed..d3465871a4 100644
--- a/hw/ppc/spapr_caps.c
+++ b/hw/ppc/spapr_caps.c
@@ -522,7 +522,8 @@ static void cap_fwnmi_apply(SpaprMachineState *spapr, 
uint8_t val,
     } else if (kvm_enabled()) {
         if (kvmppc_set_fwnmi() < 0) {
             error_setg(errp, "Firmware Assisted Non-Maskable Interrupts(FWNMI) 
"
-                             "not supported by KVM.");
+                             "not supported by KVM, "
+                             "try appending -machine cap-fwnmi=off");
         }
     }
 }
@@ -647,6 +648,10 @@ static SpaprCapabilities 
default_caps_with_cpu(SpaprMachineState *spapr,
 
     if (tcg_enabled()) {
         caps.caps[SPAPR_CAP_FWNMI] = SPAPR_CAP_OFF;
+    } else if (kvm_enabled()) {
+        if (!kvmppc_get_fwnmi()) {
+            caps.caps[SPAPR_CAP_FWNMI] = SPAPR_CAP_OFF;
+        }
     }
 
     if (!ppc_type_check_compat(cputype, CPU_POWERPC_LOGICAL_3_00,
diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index 7f44b1aa1a..718a5f6e1f 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -88,6 +88,7 @@ static int cap_ppc_safe_indirect_branch;
 static int cap_ppc_count_cache_flush_assist;
 static int cap_ppc_nested_kvm_hv;
 static int cap_large_decr;
+static int cap_fwnmi;
 
 static uint32_t debug_inst_opcode;
 
@@ -136,6 +137,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
     kvmppc_get_cpu_characteristics(s);
     cap_ppc_nested_kvm_hv = kvm_vm_check_extension(s, KVM_CAP_PPC_NESTED_HV);
     cap_large_decr = kvmppc_get_dec_bits();
+    cap_fwnmi = kvm_vm_check_extension(s, KVM_CAP_PPC_FWNMI);
     /*
      * Note: setting it to false because there is not such capability
      * in KVM at this moment.
@@ -2064,6 +2066,11 @@ void kvmppc_set_mpic_proxy(PowerPCCPU *cpu, int 
mpic_proxy)
     }
 }
 
+bool kvmppc_get_fwnmi(void)
+{
+    return cap_fwnmi;
+}
+
 int kvmppc_set_fwnmi(void)
 {
     PowerPCCPU *cpu = POWERPC_CPU(first_cpu);
diff --git a/target/ppc/kvm_ppc.h b/target/ppc/kvm_ppc.h
index 9e4f2357cc..faa72c236f 100644
--- a/target/ppc/kvm_ppc.h
+++ b/target/ppc/kvm_ppc.h
@@ -27,6 +27,7 @@ void kvmppc_enable_h_page_init(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);
+bool kvmppc_get_fwnmi(void);
 int kvmppc_set_fwnmi(void);
 int kvmppc_smt_threads(void);
 void kvmppc_error_append_smt_possible_hint(Error *const *errp);
@@ -163,6 +164,11 @@ static inline void kvmppc_set_mpic_proxy(PowerPCCPU *cpu, 
int mpic_proxy)
 {
 }
 
+static inline bool kvmppc_get_fwnmi(void)
+{
+    return false;
+}
+
 static inline int kvmppc_set_fwnmi(void)
 {
     return -1;
-- 
2.23.0