There are cases where halt polling is unwanted. For example when running
KVM on an over committed LPAR we rather want to give back the CPU to
neighbour LPARs instead of polling. Let us provide a callback that
allows architectures to disable polling.
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
include/linux/kvm_host.h | 10 ++++++++++
virt/kvm/Kconfig | 3 +++
virt/kvm/kvm_main.c | 2 +-
3 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c38cc5eb7e73..5d2bbcf0b1de 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1283,6 +1283,16 @@ static inline bool vcpu_valid_wakeup(struct kvm_vcpu *vcpu)
}
#endif /* CONFIG_HAVE_KVM_INVALID_WAKEUPS */
+#ifdef CONFIG_HAVE_KVM_NO_POLL
+/* Callback that tells if we must not poll */
+bool kvm_arch_no_poll(void);
+#else
+static inline bool kvm_arch_no_poll(void)
+{
+ return false;
+}
+#endif /* CONFIG_HAVE_KVM_NO_POLL */
+
#ifdef CONFIG_HAVE_KVM_VCPU_ASYNC_IOCTL
long kvm_arch_vcpu_async_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg);
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index ea434ddc8499..aad9284c043a 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -57,3 +57,6 @@ config HAVE_KVM_VCPU_ASYNC_IOCTL
config HAVE_KVM_VCPU_RUN_PID_CHANGE
bool
+
+config HAVE_KVM_NO_POLL
+ bool
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 076bc38963bf..c76d83532e14 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2248,7 +2248,7 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
u64 block_ns;
start = cur = ktime_get();
- if (vcpu->halt_poll_ns) {
+ if (vcpu->halt_poll_ns && !kvm_arch_no_poll()) {
ktime_t stop = ktime_add_ns(ktime_get(), vcpu->halt_poll_ns);
++vcpu->stat.halt_attempted_poll;
--
2.17.1
