On Fri, Sep 24, 2021 at 05:55:24PM -0700, Sean Christopherson wrote: > Factor out the "block" part of kvm_vcpu_halt() so that x86 can emulate > non-halt wait/sleep/block conditions that should not be subjected to > halt-polling. > > No functional change intended. > > Signed-off-by: Sean Christopherson <[email protected]>
Reviewed-by: David Matlack <[email protected]> > --- > include/linux/kvm_host.h | 1 + > virt/kvm/kvm_main.c | 50 ++++++++++++++++++++++++++++------------ > 2 files changed, 36 insertions(+), 15 deletions(-) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index d2a8be3fb9ba..655c2b24db2d 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -966,6 +966,7 @@ void kvm_sigset_activate(struct kvm_vcpu *vcpu); > void kvm_sigset_deactivate(struct kvm_vcpu *vcpu); > > void kvm_vcpu_halt(struct kvm_vcpu *vcpu); > +bool kvm_vcpu_block(struct kvm_vcpu *vcpu); > void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu); > void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu); > bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu); > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 280cf1dca7db..fe34457530c2 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -3199,6 +3199,34 @@ static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu) > return ret; > } > > +/* > + * Block the vCPU until the vCPU is runnable, an event arrives, or a signal > is > + * pending. This is mostly used when halting a vCPU, but may also be used > + * directly for other vCPU non-runnable states, e.g. x86's Wait-For-SIPI. > + */ > +bool kvm_vcpu_block(struct kvm_vcpu *vcpu) > +{ > + bool waited = false; > + > + kvm_arch_vcpu_blocking(vcpu); > + > + prepare_to_rcuwait(&vcpu->wait); > + for (;;) { > + set_current_state(TASK_INTERRUPTIBLE); > + > + if (kvm_vcpu_check_block(vcpu) < 0) > + break; > + > + waited = true; > + schedule(); > + } > + finish_rcuwait(&vcpu->wait); > + > + kvm_arch_vcpu_unblocking(vcpu); > + > + return waited; > +} > + > static inline void update_halt_poll_stats(struct kvm_vcpu *vcpu, ktime_t > start, > ktime_t end, bool success) > { > @@ -3221,6 +3249,12 @@ static inline void update_halt_poll_stats(struct > kvm_vcpu *vcpu, ktime_t start, > } > } > > +/* > + * Emulate a vCPU halt condition, e.g. HLT on x86, WFI on arm, etc... If > halt > + * polling is enabled, busy wait for a short time before blocking to avoid > the > + * expensive block+unblock sequence if a wake event arrives soon after the > vCPU > + * is halted. > + */ > void kvm_vcpu_halt(struct kvm_vcpu *vcpu) > { > bool halt_poll_allowed = !kvm_arch_no_poll(vcpu); > @@ -3245,21 +3279,7 @@ void kvm_vcpu_halt(struct kvm_vcpu *vcpu) > } while (kvm_vcpu_can_poll(cur, stop)); > } > > - kvm_arch_vcpu_blocking(vcpu); > - > - prepare_to_rcuwait(&vcpu->wait); > - for (;;) { > - set_current_state(TASK_INTERRUPTIBLE); > - > - if (kvm_vcpu_check_block(vcpu) < 0) > - break; > - > - waited = true; > - schedule(); > - } > - finish_rcuwait(&vcpu->wait); > - > - kvm_arch_vcpu_unblocking(vcpu); > + waited = kvm_vcpu_block(vcpu); > > cur = ktime_get(); > if (waited) { > -- > 2.33.0.685.g46640cef36-goog > _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
