When setting up a notifier for Hyper-V event connection, attempt to use
the KVM-assisted one first, and fall back to userspace handling of the
hypercall if the kernel doesn't provide the requested feature.
Signed-off-by: Roman Kagan <rka...@virtuozzo.com>
---
include/sysemu/kvm.h | 1 +
accel/kvm/kvm-all.c | 15 +++++++++++++++
target/i386/hyperv.c | 21 ++++++++++++++++++++-
3 files changed, 36 insertions(+), 1 deletion(-)
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index bbf12a1723..70ad0a54b7 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -496,6 +496,7 @@ void kvm_irqchip_set_qemuirq_gsi(KVMState *s, qemu_irq irq,
int gsi);
void kvm_pc_gsi_handler(void *opaque, int n, int level);
void kvm_pc_setup_irq_routing(bool pci_enabled);
void kvm_init_irq_routing(KVMState *s);
+int kvm_set_hv_event_notifier(KVMState *s, uint32_t conn_id, EventNotifier *n);
/**
* kvm_arch_irqchip_create:
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index f290f487a5..c3ba87b701 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1423,6 +1423,21 @@ static void kvm_irqchip_create(MachineState *machine,
KVMState *s)
s->gsimap = g_hash_table_new(g_direct_hash, g_direct_equal);
}
+int kvm_set_hv_event_notifier(KVMState *s, uint32_t conn_id, EventNotifier *n)
+{
+ struct kvm_hyperv_eventfd hvevfd = {
+ .conn_id = conn_id,
+ .fd = n ? event_notifier_get_fd(n) : -1,
+ .flags = n ? 0 : KVM_HYPERV_EVENTFD_DEASSIGN,
+ };
+
+ if (!kvm_check_extension(s, KVM_CAP_HYPERV_EVENTFD)) {
+ return -ENOSYS;
+ }
+
+ return kvm_vm_ioctl(s, KVM_HYPERV_EVENTFD, &hvevfd);
+}
+
/* Find number of supported CPUs using the recommended
* procedure from the kernel API documentation to cope with
* older kernels that may be missing capabilities.
diff --git a/target/i386/hyperv.c b/target/i386/hyperv.c
index e43cbb9322..63dcb23fa8 100644
--- a/target/i386/hyperv.c
+++ b/target/i386/hyperv.c
@@ -313,7 +313,8 @@ unlock:
return ret;
}
-int hyperv_set_evt_notifier(uint32_t conn_id, EventNotifier *notifier)
+static int hyperv_set_evt_notifier_userspace(uint32_t conn_id,
+ EventNotifier *notifier)
{
int ret;
EvtHandler *eh;
@@ -346,6 +347,24 @@ unlock:
return ret;
}
+static bool hv_evt_notifier_userspace;
+
+int hyperv_set_evt_notifier(uint32_t conn_id, EventNotifier *notifier)
+{
+ if (!hv_evt_notifier_userspace) {
+ int ret = kvm_set_hv_event_notifier(kvm_state, conn_id, notifier);
+ if (ret != -ENOSYS) {
+ return ret;
+ }
+
+ hv_evt_notifier_userspace = true;
+ warn_report("Hyper-V event signaling in KVM not supported; "
+ "using slower userspace hypercall processing");
+ }
+
+ return hyperv_set_evt_notifier_userspace(conn_id, notifier);
+}
+
static uint64_t hvcall_post_message(uint64_t param, bool fast)
{
uint64_t ret;
--
2.14.3
