From: Christoffer Dall <cdall@linaro.org>
To: Andrew Jones <drjones@redhat.com>
Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
marc.zyngier@arm.com, pbonzini@redhat.com, rkrcmar@redhat.com
Subject: Re: [PATCH v4 05/11] KVM: arm/arm64: replace pause checks with vcpu request checks
Date: Thu, 1 Jun 2017 12:35:08 +0200 [thread overview]
Message-ID: <20170601103508.GD20919@cbox> (raw)
In-Reply-To: <20170516022035.7674-6-drjones@redhat.com>
On Tue, May 16, 2017 at 04:20:29AM +0200, Andrew Jones wrote:
> The current use of KVM_REQ_VCPU_EXIT for pause is fine. Even the
> requester clearing the request is OK, as this is the special case
> where the sole requesting thread and receiving VCPU are executing
> synchronously (see "Clearing Requests" in
> Documentation/virtual/kvm/vcpu-requests.rst) However, that's about
> to change, so let's ensure only the receiving VCPU clears the
> request. Additionally, by guaranteeing KVM_REQ_VCPU_EXIT is always
> set when pause is, we can avoid checking pause directly in VCPU RUN.
>
> Signed-off-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
> ---
> virt/kvm/arm/arm.c | 20 +++++++++++++++++---
> 1 file changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> index 138212605ad9..21a4db90073f 100644
> --- a/virt/kvm/arm/arm.c
> +++ b/virt/kvm/arm/arm.c
> @@ -546,7 +546,6 @@ void kvm_arm_resume_guest(struct kvm *kvm)
>
> kvm_for_each_vcpu(i, vcpu, kvm) {
> vcpu->arch.pause = false;
> - kvm_clear_request(KVM_REQ_VCPU_EXIT, vcpu);
> swake_up(kvm_arch_vcpu_wq(vcpu));
> }
> }
> @@ -557,6 +556,11 @@ static void vcpu_sleep(struct kvm_vcpu *vcpu)
>
> swait_event_interruptible(*wq, ((!vcpu->arch.power_off) &&
> (!vcpu->arch.pause)));
> +
> + if (vcpu->arch.pause) {
> + /* Awaken to handle a signal, request we sleep again later. */
> + kvm_make_request(KVM_REQ_VCPU_EXIT, vcpu);
> + }
> }
>
> static int kvm_vcpu_initialized(struct kvm_vcpu *vcpu)
> @@ -564,6 +568,14 @@ static int kvm_vcpu_initialized(struct kvm_vcpu *vcpu)
> return vcpu->arch.target >= 0;
> }
>
> +static void check_vcpu_requests(struct kvm_vcpu *vcpu)
> +{
> + if (kvm_request_pending(vcpu)) {
> + if (kvm_check_request(KVM_REQ_VCPU_EXIT, vcpu))
> + vcpu_sleep(vcpu);
> + }
> +}
> +
> /**
> * kvm_arch_vcpu_ioctl_run - the main VCPU run function to execute guest code
> * @vcpu: The VCPU pointer
> @@ -609,7 +621,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
>
> update_vttbr(vcpu->kvm);
>
> - if (vcpu->arch.power_off || vcpu->arch.pause)
> + check_vcpu_requests(vcpu);
> +
> + if (vcpu->arch.power_off)
> vcpu_sleep(vcpu);
>
> /*
> @@ -649,7 +663,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
>
> if (ret <= 0 || need_new_vmid_gen(vcpu->kvm) ||
> kvm_request_pending(vcpu) ||
> - vcpu->arch.power_off || vcpu->arch.pause) {
> + vcpu->arch.power_off) {
> vcpu->mode = OUTSIDE_GUEST_MODE;
> local_irq_enable();
> kvm_pmu_sync_hwstate(vcpu);
> --
> 2.9.3
>
next prev parent reply other threads:[~2017-06-01 10:35 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-16 2:20 [PATCH v4 00/11] KVM: arm/arm64: race fixes and vcpu requests Andrew Jones
2017-05-16 2:20 ` [PATCH v4 01/11] KVM: improve arch vcpu request defining Andrew Jones
2017-06-01 10:34 ` Christoffer Dall
2017-05-16 2:20 ` [PATCH v4 02/11] KVM: add kvm_request_pending Andrew Jones
2017-06-01 10:35 ` Christoffer Dall
2017-05-16 2:20 ` [PATCH v4 03/11] KVM: Add documentation for VCPU requests Andrew Jones
2017-05-26 7:31 ` Christoffer Dall
2017-05-26 9:43 ` Andrew Jones
2017-05-16 2:20 ` [PATCH v4 04/11] KVM: arm/arm64: properly use vcpu requests Andrew Jones
2017-05-16 2:20 ` [PATCH v4 05/11] KVM: arm/arm64: replace pause checks with vcpu request checks Andrew Jones
2017-06-01 10:35 ` Christoffer Dall [this message]
2017-05-16 2:20 ` [PATCH v4 06/11] KVM: arm/arm64: use vcpu requests for power_off Andrew Jones
2017-06-01 10:35 ` Christoffer Dall
2017-06-01 10:35 ` Christoffer Dall
2017-05-16 2:20 ` [PATCH v4 07/11] KVM: arm/arm64: optimize VCPU RUN Andrew Jones
2017-06-01 10:35 ` Christoffer Dall
2017-05-16 2:20 ` [PATCH v4 08/11] KVM: arm/arm64: change exit request to sleep request Andrew Jones
2017-06-01 10:35 ` Christoffer Dall
2017-05-16 2:20 ` [PATCH v4 09/11] KVM: arm/arm64: use vcpu requests for irq injection Andrew Jones
2017-06-01 10:35 ` Christoffer Dall
2017-06-01 10:59 ` Andrew Jones
2017-06-01 13:27 ` Christoffer Dall
2017-06-01 13:38 ` Andrew Jones
2017-06-01 13:53 ` Christoffer Dall
2017-05-16 2:20 ` [PATCH v4 10/11] KVM: arm/arm64: PMU: remove request-less vcpu kick Andrew Jones
2017-05-16 2:20 ` [PATCH v4 11/11] KVM: arm/arm64: timer: " Andrew Jones
2017-06-01 10:34 ` Christoffer Dall
2017-06-01 11:09 ` Andrew Jones
2017-06-01 12:37 ` Paolo Bonzini
2017-06-01 13:23 ` Christoffer Dall
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