| Message ID | 20190416180158.112309-2-borntraeger@de.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | disabling halt polling for nested virtualization | expand |
On Tue, 16 Apr 2019 20:01:57 +0200 Christian Borntraeger <borntraeger@de.ibm.com> wrote: > 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@de.ibm.com> > Acked-by: Paolo Bonzini <pbonzini@redhat.com> > --- > include/linux/kvm_host.h | 10 ++++++++++ > virt/kvm/Kconfig | 3 +++ > virt/kvm/kvm_main.c | 2 +- > 3 files changed, 14 insertions(+), 1 deletion(-) Reviewed-by: Cornelia Huck <cohuck@redhat.com>
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 9d55c63db09b..b3aff1a3f633 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1305,6 +1305,16 @@ 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(struct kvm_vcpu *vcpu); +#else +static inline bool kvm_arch_no_poll(struct kvm_vcpu *vcpu) +{ + 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 55fe8e20d8fd..23aec2f4ba71 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2253,7 +2253,7 @@ 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(vcpu)) { ktime_t stop = ktime_add_ns(ktime_get(), vcpu->halt_poll_ns); ++vcpu->stat.halt_attempted_poll;