kvm: require KVM_IRQFD for kernel irqchip

KVM_IRQFD was introduced in Linux 2.6.32, and since then it has always been
available on architectures that support an in-kernel interrupt controller.
We can require it unconditionally.

Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

5 files changed, 10 insertions, 14 deletions

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 0c7b0569da..be50d47f7b 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -91,7 +91,6 @@ bool kvm_split_irqchip;
 bool kvm_async_interrupts_allowed;
 bool kvm_halt_in_kernel_allowed;
 bool kvm_eventfds_allowed;
-bool kvm_irqfds_allowed;
 bool kvm_resamplefds_allowed;
 bool kvm_msi_via_irqfd_allowed;
 bool kvm_gsi_routing_allowed;
@@ -2128,10 +2127,6 @@ static int kvm_irqchip_assign_irqfd(KVMState *s, EventNotifier *event,
         }
     }
 
-    if (!kvm_irqfds_enabled()) {
-        return -ENOSYS;
-    }
-
     return kvm_vm_ioctl(s, KVM_IRQFD, &irqfd);
 }
 
@@ -2292,6 +2287,11 @@ static void kvm_irqchip_create(KVMState *s)
         return;
     }
 
+    if (kvm_check_extension(s, KVM_CAP_IRQFD) <= 0) {
+        fprintf(stderr, "kvm: irqfd not implemented\n");
+        exit(1);
+    }
+
     /* First probe and see if there's a arch-specific hook to create the
      * in-kernel irqchip for us */
     ret = kvm_arch_irqchip_create(s);
@@ -2589,9 +2589,6 @@ static int kvm_init(MachineState *ms)
     kvm_eventfds_allowed =
         (kvm_check_extension(s, KVM_CAP_IOEVENTFD) > 0);
 
-    kvm_irqfds_allowed =
-        (kvm_check_extension(s, KVM_CAP_IRQFD) > 0);
-
     kvm_resamplefds_allowed =
         (kvm_check_extension(s, KVM_CAP_IRQFD_RESAMPLE) > 0);
 
diff --git a/accel/stubs/kvm-stub.c b/accel/stubs/kvm-stub.c
index bce005adad..19d58f2778 100644
--- a/accel/stubs/kvm-stub.c
+++ b/accel/stubs/kvm-stub.c
@@ -18,7 +18,6 @@ KVMState *kvm_state;
 bool kvm_kernel_irqchip;
 bool kvm_async_interrupts_allowed;
 bool kvm_eventfds_allowed;
-bool kvm_irqfds_allowed;
 bool kvm_resamplefds_allowed;
 bool kvm_msi_via_irqfd_allowed;
 bool kvm_gsi_routing_allowed;
diff --git a/hw/intc/arm_gicv3_its_kvm.c b/hw/intc/arm_gicv3_its_kvm.c
index 61c1cc7bdb..f7df602cff 100644
--- a/hw/intc/arm_gicv3_its_kvm.c
+++ b/hw/intc/arm_gicv3_its_kvm.c
@@ -123,7 +123,7 @@ static void kvm_arm_its_realize(DeviceState *dev, Error **errp)
 
     kvm_msi_use_devid = true;
     kvm_gsi_direct_mapping = false;
-    kvm_msi_via_irqfd_allowed = kvm_irqfds_enabled();
+    kvm_msi_via_irqfd_allowed = true;
 }
 
 /**
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index 93dccf5dd9..575dee53b3 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -37,7 +37,6 @@ extern bool kvm_split_irqchip;
 extern bool kvm_async_interrupts_allowed;
 extern bool kvm_halt_in_kernel_allowed;
 extern bool kvm_eventfds_allowed;
-extern bool kvm_irqfds_allowed;
 extern bool kvm_resamplefds_allowed;
 extern bool kvm_msi_via_irqfd_allowed;
 extern bool kvm_gsi_routing_allowed;
@@ -102,8 +101,10 @@ extern bool kvm_msi_use_devid;
  * Returns: true if we can use irqfds to inject interrupts into
  * a KVM CPU (ie the kernel supports irqfds and we are running
  * with a configuration where it is meaningful to use them).
+ *
+ * Always available if running with in-kernel irqchip.
  */
-#define kvm_irqfds_enabled() (kvm_irqfds_allowed)
+#define kvm_irqfds_enabled() kvm_irqchip_in_kernel()
 
 /**
  * kvm_resamplefds_enabled:
@@ -167,7 +168,6 @@ extern bool kvm_msi_use_devid;
 #define kvm_async_interrupts_enabled() (false)
 #define kvm_halt_in_kernel() (false)
 #define kvm_eventfds_enabled() (false)
-#define kvm_irqfds_enabled() (false)
 #define kvm_resamplefds_enabled() (false)
 #define kvm_msi_via_irqfd_enabled() (false)
 #define kvm_gsi_routing_allowed() (false)
diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
index 090d617627..26e68c7ab4 100644
--- a/target/riscv/kvm/kvm-cpu.c
+++ b/target/riscv/kvm/kvm-cpu.c
@@ -1420,7 +1420,7 @@ void kvm_riscv_aia_create(MachineState *machine, uint64_t group_shift,
         exit(1);
     }
 
-    kvm_msi_via_irqfd_allowed = kvm_irqfds_enabled();
+    kvm_msi_via_irqfd_allowed = true;
 }
 
 static void kvm_cpu_instance_init(CPUState *cs)