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Message-Id: <20210925005528.1145584-15-seanjc@google.com> Date: Fri, 24 Sep 2021 17:55:28 -0700 From: Sean Christopherson <seanjc@...gle.com> To: Marc Zyngier <maz@...nel.org>, Huacai Chen <chenhuacai@...nel.org>, Aleksandar Markovic <aleksandar.qemu.devel@...il.com>, Paul Mackerras <paulus@...abs.org>, Christian Borntraeger <borntraeger@...ibm.com>, Janosch Frank <frankja@...ux.ibm.com>, Paolo Bonzini <pbonzini@...hat.com> Cc: James Morse <james.morse@....com>, Alexandru Elisei <alexandru.elisei@....com>, Suzuki K Poulose <suzuki.poulose@....com>, David Hildenbrand <david@...hat.com>, Cornelia Huck <cohuck@...hat.com>, Claudio Imbrenda <imbrenda@...ux.ibm.com>, Sean Christopherson <seanjc@...gle.com>, Vitaly Kuznetsov <vkuznets@...hat.com>, Wanpeng Li <wanpengli@...cent.com>, Jim Mattson <jmattson@...gle.com>, Joerg Roedel <joro@...tes.org>, linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu, linux-mips@...r.kernel.org, kvm@...r.kernel.org, kvm-ppc@...r.kernel.org, linux-kernel@...r.kernel.org, David Matlack <dmatlack@...gle.com>, Jing Zhang <jingzhangos@...gle.com> Subject: [PATCH 14/14] KVM: x86: Invoke kvm_vcpu_block() directly for non-HALTED wait states Call kvm_vcpu_block() directly for all wait states except HALTED so that kvm_vcpu_halt() is no longer a misnomer on x86. Functionally, this means KVM will never attempt halt-polling or adjust vcpu->halt_poll_ns for INIT_RECEIVED (a.k.a. Wait-For-SIPI (WFS)) or AP_RESET_HOLD; UNINITIALIZED is handled in kvm_arch_vcpu_ioctl_run(), and x86 doesn't use any other "wait" states. As mentioned above, the motivation of this is purely so that "halt" isn't overloaded on x86, e.g. in KVM's stats. Skipping halt-polling for WFS (and RESET_HOLD) has no meaningful effect on guest performance as there are typically single-digit numbers of INIT-SIPI sequences per AP vCPU, per boot, versus thousands of HLTs just to boot to console. Signed-off-by: Sean Christopherson <seanjc@...gle.com> --- arch/x86/kvm/x86.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b444f9315766..a0f313c4bc49 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9893,7 +9893,10 @@ 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_halt(vcpu); + if (vcpu->arch.mp_state == KVM_MP_STATE_HALTED) + kvm_vcpu_halt(vcpu); + else + kvm_vcpu_block(vcpu); vcpu->srcu_idx = srcu_read_lock(&kvm->srcu); if (kvm_x86_ops.post_block) -- 2.33.0.685.g46640cef36-goog
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