From patchwork Sat Oct 9 02:12:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 12546895 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F4A2C433EF for ; Sat, 9 Oct 2021 02:13:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 87A3F61058 for ; Sat, 9 Oct 2021 02:13:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244434AbhJICPt (ORCPT ); Fri, 8 Oct 2021 22:15:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38340 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244439AbhJICPb (ORCPT ); Fri, 8 Oct 2021 22:15:31 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C158C0613EE for ; Fri, 8 Oct 2021 19:13:17 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id s6-20020a254506000000b005b6b6434cd6so14970796yba.9 for ; Fri, 08 Oct 2021 19:13:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=reply-to:date:in-reply-to:message-id:mime-version:references :subject:from:to:cc; bh=A16ghZapKabIxKpJvSoekuSQb+2m0ovUg31JfH4Wpyk=; b=gXKY8WPbOOd7VUk2uZNjE2h38k02X7HYo+DeTvCyrUtBDVFLTYEsOV8HSoTA+FvX50 6RKQel33Gtt9tZeSd/S1b5Fq4WSdHPmoxsRRolUsJs1RknoixjMGUTdHEj46Nu5OvT+D veVzIN6kL3lune6PqMLQN/YznPFV5x8H61PddtU3baQVQe6kcDq8AGdLFfWuVrLQ8EQf j+yjtMDopjwkS57GjAxolElfps1MfrQZh9wMiAPKNI3vZMMMUZ0Se8uxReg+fzG8sQAm DKcW2fuPnHMCOALfdqBDt6VllQOh4ktUmrRkK5ZhDt5ivim69QDNok10m3K5kTH0AXbg hPJA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:reply-to:date:in-reply-to:message-id :mime-version:references:subject:from:to:cc; bh=A16ghZapKabIxKpJvSoekuSQb+2m0ovUg31JfH4Wpyk=; b=22fG/qYac7a/mHIvhb6Y4z7Fbtzm1C5XbiC9yJUCVWo2HYpQ3QBz+fPVtmw3hPghOh 8GzZsPAepKsx0FfLkd4RNJVUjXG1BSZ7cON8OGnQv+xYF1nrVnyxnse//LWo0Wo3Wb/e v/KUV8k/u97chOpEPkCFjyjJgA5VZxOepfOCuxlPSOu0u2dca6m+QeU8it/cMpWZ6TPu 6udHdJw4+3QJZv/x8oQurSfqNyXEoVtaAQ0mxHFoLO8EAVpbfjBgohtxvxngHrKqPfIu mQYpRPqYhNQolkhfQFisWjIYz7JXBmSRMBJgxzL9dhpreZ+3RfNc2UCoBLMSoiSU3imm Wbrw== X-Gm-Message-State: AOAM5305lFdAbfquRtU2sGCXswG0gb8Y88bm27X9aX1dTILa/KFdYHxD cAssxQLAq3MM4PmvzhSFCL5aFIk/DvA= X-Google-Smtp-Source: ABdhPJyJ+GZrMSH71hr19sRLkQaSLa+OLA+oV25ZdCvzXSyS8FSLewbkBuw4xbZrikejj+zWUKwWlVBuMgU= X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:90:200:e39b:6333:b001:cb]) (user=seanjc job=sendgmr) by 2002:a25:1d57:: with SMTP id d84mr8116571ybd.410.1633745596490; Fri, 08 Oct 2021 19:13:16 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 8 Oct 2021 19:12:07 -0700 In-Reply-To: <20211009021236.4122790-1-seanjc@google.com> Message-Id: <20211009021236.4122790-15-seanjc@google.com> Mime-Version: 1.0 References: <20211009021236.4122790-1-seanjc@google.com> X-Mailer: git-send-email 2.33.0.882.g93a45727a2-goog Subject: [PATCH v2 14/43] KVM: Split out a kvm_vcpu_block() helper from kvm_vcpu_halt() From: Sean Christopherson To: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Paul Mackerras , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Paolo Bonzini Cc: James Morse , Alexandru Elisei , Suzuki K Poulose , Atish Patra , David Hildenbrand , Cornelia Huck , Claudio Imbrenda , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , 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, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, David Matlack , Oliver Upton , Jing Zhang Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org 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. Reviewed-by: Christian Borntraeger Reviewed-by: David Matlack Signed-off-by: Sean Christopherson --- include/linux/kvm_host.h | 1 + virt/kvm/kvm_main.c | 52 +++++++++++++++++++++++++++------------- 2 files changed, 37 insertions(+), 16 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index c2ea4004553a..2d837e06eeec 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -968,6 +968,7 @@ 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 c13bf3367fda..42894ff7c474 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3201,6 +3201,35 @@ 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) +{ + struct rcuwait *wait = kvm_arch_vcpu_get_wait(vcpu); + bool waited = false; + + kvm_arch_vcpu_blocking(vcpu); + + prepare_to_rcuwait(wait); + for (;;) { + set_current_state(TASK_INTERRUPTIBLE); + + if (kvm_vcpu_check_block(vcpu) < 0) + break; + + waited = true; + schedule(); + } + finish_rcuwait(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) { @@ -3223,9 +3252,14 @@ 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) { - struct rcuwait *wait = kvm_arch_vcpu_get_wait(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; @@ -3248,21 +3282,7 @@ void kvm_vcpu_halt(struct kvm_vcpu *vcpu) } while (kvm_vcpu_can_poll(cur, stop)); } - kvm_arch_vcpu_blocking(vcpu); - - prepare_to_rcuwait(wait); - for (;;) { - set_current_state(TASK_INTERRUPTIBLE); - - if (kvm_vcpu_check_block(vcpu) < 0) - break; - - waited = true; - schedule(); - } - finish_rcuwait(wait); - - kvm_arch_vcpu_unblocking(vcpu); + waited = kvm_vcpu_block(vcpu); cur = ktime_get(); if (waited) {