From: Michael Mueller <mimu@xxxxxxxxxxxxxxxxxx>
The function kvm_arch_vcpu_dont_yield() allows the platform dependant
extension of the heuristic being used to identify unsuitable virtual cpus
during undirected yield processing.
The default implementation used the existing waitqueue check.
Signed-off-by: Michael Mueller <mimu@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
include/linux/kvm_host.h | 9 +++++++++
virt/kvm/Kconfig | 3 +++
virt/kvm/kvm_main.c | 2 +-
3 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index f5937b8..3e979a2 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -686,6 +686,15 @@ static inline wait_queue_head_t *kvm_arch_vcpu_wq(struct kvm_vcpu *vcpu)
#endif
}
+#ifndef CONFIG_HAVE_KVM_ARCH_VCPU_DONT_YIELD
+static inline bool kvm_arch_vcpu_dont_yield(struct kvm_vcpu *vcpu)
+{
+ return waitqueue_active(kvm_arch_vcpu_wq(vcpu));
+}
+#else
+bool kvm_arch_vcpu_dont_yield(struct kvm_vcpu *vcpu);
+#endif
+
int kvm_arch_init_vm(struct kvm *kvm, unsigned long type);
void kvm_arch_destroy_vm(struct kvm *kvm);
void kvm_arch_sync_events(struct kvm *kvm);
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index 13f2d19..e1e46a8 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -34,3 +34,6 @@ config HAVE_KVM_CPU_RELAX_INTERCEPT
config KVM_VFIO
bool
+
+config HAVE_KVM_ARCH_VCPU_DONT_YIELD
+ bool
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a9e999a..6829e6f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1804,7 +1804,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me)
continue;
if (vcpu == me)
continue;
- if (waitqueue_active(&vcpu->wq))
+ if (kvm_arch_vcpu_dont_yield(vcpu))
continue;
if (!kvm_vcpu_eligible_for_directed_yield(vcpu))
continue;
--
1.8.4.2
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