On Fri, Sep 24, 2021 at 05:55:23PM -0700, Sean Christopherson wrote:
> Rename kvm_vcpu_block() to kvm_vcpu_halt() in preparation for splitting
> the actual "block" sequences into a separate helper (to be named
> kvm_vcpu_block()).  x86 will use the standalone block-only path to handle
> non-halt cases where the vCPU is not runnable.
> 
> Rename block_ns to halt_ns to match the new function name.
> 
> Opportunistically move an x86-specific comment to x86, and enhance it, too.
> 
> No functional change intended.
> 
> Signed-off-by: Sean Christopherson <[email protected]>

Reviewed-by: David Matlack <[email protected]>

> ---
>  arch/arm64/kvm/arch_timer.c       |  2 +-
>  arch/arm64/kvm/handle_exit.c      |  4 ++--
>  arch/arm64/kvm/psci.c             |  2 +-
>  arch/mips/kvm/emulate.c           |  2 +-
>  arch/powerpc/kvm/book3s_pr.c      |  2 +-
>  arch/powerpc/kvm/book3s_pr_papr.c |  2 +-
>  arch/powerpc/kvm/booke.c          |  2 +-
>  arch/powerpc/kvm/powerpc.c        |  2 +-
>  arch/s390/kvm/interrupt.c         |  2 +-
>  arch/x86/kvm/x86.c                | 11 +++++++++--
>  include/linux/kvm_host.h          |  2 +-
>  virt/kvm/kvm_main.c               | 20 +++++++++-----------
>  12 files changed, 29 insertions(+), 24 deletions(-)
> 
> diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
> index 3df67c127489..7e8396f74010 100644
> --- a/arch/arm64/kvm/arch_timer.c
> +++ b/arch/arm64/kvm/arch_timer.c
> @@ -467,7 +467,7 @@ static void timer_save_state(struct arch_timer_context 
> *ctx)
>  }
>  
>  /*
> - * Schedule the background timer before calling kvm_vcpu_block, so that this
> + * Schedule the background timer before calling kvm_vcpu_halt, so that this
>   * thread is removed from its waitqueue and made runnable when there's a 
> timer
>   * interrupt to handle.
>   */
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index 275a27368a04..08f823984712 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -82,7 +82,7 @@ static int handle_no_fpsimd(struct kvm_vcpu *vcpu)
>   *
>   * WFE: Yield the CPU and come back to this vcpu when the scheduler
>   * decides to.
> - * WFI: Simply call kvm_vcpu_block(), which will halt execution of
> + * WFI: Simply call kvm_vcpu_halt(), which will halt execution of
>   * world-switches and schedule other host processes until there is an
>   * incoming IRQ or FIQ to the VM.
>   */
> @@ -95,7 +95,7 @@ static int kvm_handle_wfx(struct kvm_vcpu *vcpu)
>       } else {
>               trace_kvm_wfx_arm64(*vcpu_pc(vcpu), false);
>               vcpu->stat.wfi_exit_stat++;
> -             kvm_vcpu_block(vcpu);
> +             kvm_vcpu_halt(vcpu);
>               kvm_clear_request(KVM_REQ_UNHALT, vcpu);
>       }
>  
> diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
> index 74c47d420253..e275b2ca08b9 100644
> --- a/arch/arm64/kvm/psci.c
> +++ b/arch/arm64/kvm/psci.c
> @@ -46,7 +46,7 @@ static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu 
> *vcpu)
>        * specification (ARM DEN 0022A). This means all suspend states
>        * for KVM will preserve the register state.
>        */
> -     kvm_vcpu_block(vcpu);
> +     kvm_vcpu_halt(vcpu);
>       kvm_clear_request(KVM_REQ_UNHALT, vcpu);
>  
>       return PSCI_RET_SUCCESS;
> diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
> index 22e745e49b0a..b494d8d39290 100644
> --- a/arch/mips/kvm/emulate.c
> +++ b/arch/mips/kvm/emulate.c
> @@ -952,7 +952,7 @@ enum emulation_result kvm_mips_emul_wait(struct kvm_vcpu 
> *vcpu)
>       if (!vcpu->arch.pending_exceptions) {
>               kvm_vz_lose_htimer(vcpu);
>               vcpu->arch.wait = 1;
> -             kvm_vcpu_block(vcpu);
> +             kvm_vcpu_halt(vcpu);
>  
>               /*
>                * We we are runnable, then definitely go off to user space to
> diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
> index 6bc9425acb32..0ced1b16f0e5 100644
> --- a/arch/powerpc/kvm/book3s_pr.c
> +++ b/arch/powerpc/kvm/book3s_pr.c
> @@ -492,7 +492,7 @@ static void kvmppc_set_msr_pr(struct kvm_vcpu *vcpu, u64 
> msr)
>  
>       if (msr & MSR_POW) {
>               if (!vcpu->arch.pending_exceptions) {
> -                     kvm_vcpu_block(vcpu);
> +                     kvm_vcpu_halt(vcpu);
>                       kvm_clear_request(KVM_REQ_UNHALT, vcpu);
>                       vcpu->stat.generic.halt_wakeup++;
>  
> diff --git a/arch/powerpc/kvm/book3s_pr_papr.c 
> b/arch/powerpc/kvm/book3s_pr_papr.c
> index ac14239f3424..1f10e7dfcdd0 100644
> --- a/arch/powerpc/kvm/book3s_pr_papr.c
> +++ b/arch/powerpc/kvm/book3s_pr_papr.c
> @@ -376,7 +376,7 @@ int kvmppc_h_pr(struct kvm_vcpu *vcpu, unsigned long cmd)
>               return kvmppc_h_pr_stuff_tce(vcpu);
>       case H_CEDE:
>               kvmppc_set_msr_fast(vcpu, kvmppc_get_msr(vcpu) | MSR_EE);
> -             kvm_vcpu_block(vcpu);
> +             kvm_vcpu_halt(vcpu);
>               kvm_clear_request(KVM_REQ_UNHALT, vcpu);
>               vcpu->stat.generic.halt_wakeup++;
>               return EMULATE_DONE;
> diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
> index 977801c83aff..12abffa40cd9 100644
> --- a/arch/powerpc/kvm/booke.c
> +++ b/arch/powerpc/kvm/booke.c
> @@ -718,7 +718,7 @@ int kvmppc_core_prepare_to_enter(struct kvm_vcpu *vcpu)
>  
>       if (vcpu->arch.shared->msr & MSR_WE) {
>               local_irq_enable();
> -             kvm_vcpu_block(vcpu);
> +             kvm_vcpu_halt(vcpu);
>               kvm_clear_request(KVM_REQ_UNHALT, vcpu);
>               hard_irq_disable();
>  
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> index 8ab90ce8738f..565eed2dab81 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -236,7 +236,7 @@ int kvmppc_kvm_pv(struct kvm_vcpu *vcpu)
>               break;
>       case EV_HCALL_TOKEN(EV_IDLE):
>               r = EV_SUCCESS;
> -             kvm_vcpu_block(vcpu);
> +             kvm_vcpu_halt(vcpu);
>               kvm_clear_request(KVM_REQ_UNHALT, vcpu);
>               break;
>       default:
> diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
> index 520450a7956f..10bd648170b7 100644
> --- a/arch/s390/kvm/interrupt.c
> +++ b/arch/s390/kvm/interrupt.c
> @@ -1335,7 +1335,7 @@ int kvm_s390_handle_wait(struct kvm_vcpu *vcpu)
>       VCPU_EVENT(vcpu, 4, "enabled wait: %llu ns", sltime);
>  no_timer:
>       srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
> -     kvm_vcpu_block(vcpu);
> +     kvm_vcpu_halt(vcpu);
>       vcpu->valid_wakeup = false;
>       __unset_cpu_idle(vcpu);
>       vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index eade8a2bdccf..0d71c73a61bb 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -8645,6 +8645,13 @@ void kvm_arch_exit(void)
>  
>  static int __kvm_emulate_halt(struct kvm_vcpu *vcpu, int state, int reason)
>  {
> +     /*
> +      * The vCPU has halted, e.g. executed HLT.  Update the run state if the
> +      * local APIC is in-kernel, the run loop will detect the non-runnable
> +      * state and halt the vCPU.  Exit to userspace if the local APIC is
> +      * managed by userspace, in which case userspace is responsible for
> +      * handling wake events.
> +      */
>       ++vcpu->stat.halt_exits;
>       if (lapic_in_kernel(vcpu)) {
>               vcpu->arch.mp_state = state;
> @@ -9886,7 +9893,7 @@ static inline int vcpu_block(struct kvm *kvm, struct 
> kvm_vcpu *vcpu)
>       if (!kvm_arch_vcpu_runnable(vcpu) &&
>           (!kvm_x86_ops.pre_block || static_call(kvm_x86_pre_block)(vcpu) == 
> 0)) {
>               srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
> -             kvm_vcpu_block(vcpu);
> +             kvm_vcpu_halt(vcpu);
>               vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);
>  
>               if (kvm_x86_ops.post_block)
> @@ -10120,7 +10127,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>                       r = -EINTR;
>                       goto out;
>               }
> -             kvm_vcpu_block(vcpu);
> +             kvm_vcpu_halt(vcpu);
>               if (kvm_apic_accept_events(vcpu) < 0) {
>                       r = 0;
>                       goto out;
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 3f87d6ad20bf..d2a8be3fb9ba 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -965,7 +965,7 @@ void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, 
> gfn_t gfn);
>  void kvm_sigset_activate(struct kvm_vcpu *vcpu);
>  void kvm_sigset_deactivate(struct kvm_vcpu *vcpu);
>  
> -void kvm_vcpu_block(struct kvm_vcpu *vcpu);
> +void kvm_vcpu_halt(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 f96cda8312f3..280cf1dca7db 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -3221,16 +3221,13 @@ static inline void update_halt_poll_stats(struct 
> kvm_vcpu *vcpu, ktime_t start,
>       }
>  }
>  
> -/*
> - * The vCPU has executed a HLT instruction with in-kernel mode enabled.
> - */
> -void kvm_vcpu_block(struct kvm_vcpu *vcpu)
> +void kvm_vcpu_halt(struct kvm_vcpu *vcpu)
>  {
>       bool halt_poll_allowed = !kvm_arch_no_poll(vcpu);
>       bool do_halt_poll = halt_poll_allowed && vcpu->halt_poll_ns;
>       ktime_t start, cur, poll_end;
>       bool waited = false;
> -     u64 block_ns;
> +     u64 halt_ns;
>  
>       start = cur = poll_end = ktime_get();
>       if (do_halt_poll) {
> @@ -3273,7 +3270,8 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
>       }
>  
>  out:
> -     block_ns = ktime_to_ns(cur) - ktime_to_ns(start);
> +     /* The total time the vCPU was "halted", including polling time. */
> +     halt_ns = ktime_to_ns(cur) - ktime_to_ns(start);
>  
>       /*
>        * Note, halt-polling is considered successful so long as the vCPU was
> @@ -3287,24 +3285,24 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
>               if (!vcpu_valid_wakeup(vcpu)) {
>                       shrink_halt_poll_ns(vcpu);
>               } else if (vcpu->kvm->max_halt_poll_ns) {
> -                     if (block_ns <= vcpu->halt_poll_ns)
> +                     if (halt_ns <= vcpu->halt_poll_ns)
>                               ;
>                       /* we had a long block, shrink polling */
>                       else if (vcpu->halt_poll_ns &&
> -                                     block_ns > vcpu->kvm->max_halt_poll_ns)
> +                              halt_ns > vcpu->kvm->max_halt_poll_ns)
>                               shrink_halt_poll_ns(vcpu);
>                       /* we had a short halt and our poll time is too small */
>                       else if (vcpu->halt_poll_ns < 
> vcpu->kvm->max_halt_poll_ns &&
> -                                     block_ns < vcpu->kvm->max_halt_poll_ns)
> +                              halt_ns < vcpu->kvm->max_halt_poll_ns)
>                               grow_halt_poll_ns(vcpu);
>               } else {
>                       vcpu->halt_poll_ns = 0;
>               }
>       }
>  
> -     trace_kvm_vcpu_wakeup(block_ns, waited, vcpu_valid_wakeup(vcpu));
> +     trace_kvm_vcpu_wakeup(halt_ns, waited, vcpu_valid_wakeup(vcpu));
>  }
> -EXPORT_SYMBOL_GPL(kvm_vcpu_block);
> +EXPORT_SYMBOL_GPL(kvm_vcpu_halt);
>  
>  bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
>  {
> -- 
> 2.33.0.685.g46640cef36-goog
> 
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