From: David Matlack <dmatlack@google.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Marc Zyngier <maz@kernel.org>,
Huacai Chen <chenhuacai@kernel.org>,
Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>,
Paul Mackerras <paulus@ozlabs.org>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Janosch Frank <frankja@linux.ibm.com>,
Paolo Bonzini <pbonzini@redhat.com>,
James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
David Hildenbrand <david@redhat.com>,
Cornelia Huck <cohuck@redhat.com>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org,
kvm@vger.kernel.org, kvm-ppc@vger.kernel.org,
linux-kernel@vger.kernel.org, Jing Zhang <jingzhangos@google.com>
Subject: Re: [PATCH 09/14] KVM: Rename kvm_vcpu_block() => kvm_vcpu_halt()
Date: Tue, 28 Sep 2021 22:01:58 +0000 [thread overview]
Message-ID: <YVOQ1vxdDUQKziT+@google.com> (raw)
In-Reply-To: <20210925005528.1145584-10-seanjc@google.com>
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 <seanjc@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
> ---
> 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
>
next prev parent reply other threads:[~2021-09-28 22:02 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-25 0:55 [PATCH 00/14] KVM: Halt-polling fixes, cleanups and a new stat Sean Christopherson
2021-09-25 0:55 ` [PATCH 01/14] KVM: s390: Ensure kvm_arch_no_poll() is read once when blocking vCPU Sean Christopherson
2021-09-27 6:54 ` Christian Borntraeger
2021-09-25 0:55 ` [PATCH 02/14] KVM: Update halt-polling stats if and only if halt-polling was attempted Sean Christopherson
2021-09-28 18:57 ` David Matlack
2021-09-25 0:55 ` [PATCH 03/14] KVM: Refactor and document halt-polling stats update helper Sean Christopherson
2021-09-28 19:01 ` David Matlack
2021-09-25 0:55 ` [PATCH 04/14] KVM: Reconcile discrepancies in halt-polling stats Sean Christopherson
2021-09-28 21:26 ` David Matlack
2021-09-25 0:55 ` [PATCH 05/14] KVM: s390: Clear valid_wakeup in kvm_s390_handle_wait(), not in arch hook Sean Christopherson
2021-09-27 6:58 ` Christian Borntraeger
2021-09-25 0:55 ` [PATCH 06/14] KVM: Drop obsolete kvm_arch_vcpu_block_finish() Sean Christopherson
2021-09-27 6:58 ` Christian Borntraeger
2021-09-28 21:28 ` David Matlack
2021-09-25 0:55 ` [PATCH 07/14] KVM: Don't block+unblock when halt-polling is successful Sean Christopherson
2021-09-25 9:50 ` Marc Zyngier
2021-09-26 6:27 ` Paolo Bonzini
2021-09-26 9:02 ` Marc Zyngier
2021-09-27 17:28 ` Sean Christopherson
2021-09-28 9:24 ` Marc Zyngier
2021-09-28 16:21 ` Sean Christopherson
2021-09-30 9:36 ` Marc Zyngier
2021-09-25 0:55 ` [PATCH 08/14] KVM: x86: Tweak halt emulation helper names to free up kvm_vcpu_halt() Sean Christopherson
2021-09-28 21:59 ` David Matlack
2021-09-25 0:55 ` [PATCH 09/14] KVM: Rename kvm_vcpu_block() => kvm_vcpu_halt() Sean Christopherson
2021-09-27 7:06 ` Christian Borntraeger
2021-09-28 22:01 ` David Matlack [this message]
2021-09-25 0:55 ` [PATCH 10/14] KVM: Split out a kvm_vcpu_block() helper from kvm_vcpu_halt() Sean Christopherson
2021-09-27 7:41 ` Christian Borntraeger
2021-09-28 22:03 ` David Matlack
2021-09-25 0:55 ` [PATCH 11/14] KVM: stats: Add stat to detect if vcpu is currently blocking Sean Christopherson
2021-09-28 22:04 ` David Matlack
2021-09-25 0:55 ` [PATCH 12/14] KVM: Don't redo ktime_get() when calculating halt-polling stop/deadline Sean Christopherson
2021-09-28 22:08 ` David Matlack
2021-09-25 0:55 ` [PATCH 13/14] KVM: x86: Directly block (instead of "halting") UNINITIALIZED vCPUs Sean Christopherson
2021-09-28 22:12 ` David Matlack
2021-09-25 0:55 ` [PATCH 14/14] KVM: x86: Invoke kvm_vcpu_block() directly for non-HALTED wait states Sean Christopherson
2021-09-28 22:14 ` David Matlack
2021-09-27 7:22 ` disabling halt polling broken? (was Re: [PATCH 00/14] KVM: Halt-polling fixes, cleanups and a new stat) Christian Borntraeger
2021-09-27 14:59 ` Sean Christopherson
2021-09-27 15:03 ` Paolo Bonzini
2021-09-27 15:15 ` Sean Christopherson
2021-09-27 15:16 ` Christian Borntraeger
2021-09-27 16:58 ` David Matlack
2021-09-29 6:56 ` Christian Borntraeger
2021-09-27 17:24 ` Paolo Bonzini
2021-09-27 17:33 ` Sean Christopherson
2022-11-15 3:28 ` wangyanan (Y)
2022-11-16 17:19 ` David Matlack
2022-11-18 2:29 ` wangyanan (Y)
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