From patchwork Sat Sep 25 00:55:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 12517127 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 394CCC433F5 for ; Sat, 25 Sep 2021 00:56:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 19BC961251 for ; Sat, 25 Sep 2021 00:56:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346957AbhIYA6V (ORCPT ); Fri, 24 Sep 2021 20:58:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40322 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347545AbhIYA5i (ORCPT ); Fri, 24 Sep 2021 20:57:38 -0400 Received: from mail-qk1-x749.google.com (mail-qk1-x749.google.com [IPv6:2607:f8b0:4864:20::749]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A053DC0617A8 for ; Fri, 24 Sep 2021 17:55:53 -0700 (PDT) Received: by mail-qk1-x749.google.com with SMTP id w2-20020a3794020000b02903b54f40b442so45541025qkd.0 for ; Fri, 24 Sep 2021 17:55:53 -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=FPrvUwRoNgNi9U/w5sUiMk8txns9C/J9zkg6zAxmMUk=; b=Co6Y4RU2OAq+N8cxFZefD6arFCQ0JC5iLzm/wNQUkyHUQaJHgQOwXIreoskXNdo+n3 AzYCM2VGwVbtuc4RHRZMftKrMPewa2HdqIvv4DhOT1T4TVXUiFm+z0hCrC7zvpiF3bFI YrZJATtvuBhXvAfmLk0XrUN/qH+BPPx66OadWSbCOd95621rbYCdmUW1NH06aGo1hYK+ Xx216lgusMcmvOSwzMUUQUqsZv7pF4ciyTpPrxYAL4ksg4saB36TX8plZlhMO2dauaVz bfnWV2i9Gz80QoiefY5JGrMtQWt7jFR1u1lseg1viADOOm6p1dLSrT0hljxiuzqCT12T VcrA== 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=FPrvUwRoNgNi9U/w5sUiMk8txns9C/J9zkg6zAxmMUk=; b=DHlsOzodPDYbANzaRzy1nbVKHFNTOy2SlzdwctA6lOOwR7eGx51QDfSxjeGoybqh1K 5n6N/7vGmNMnBvL1fTxHiOArHLf8vpIIbv1Z7rpmeU1sb4x9P4zui2v6dw8KoisdHav7 yHW8Ihx5XMa5h5WeXqflPJcQRnPfbGhCD5QWim2Z3nTLK0VQdlwdOQhVPmAs8Ez4wBHO 4MdszD+jNuYpXEpE4xVq8Ivi7ZEtL9RJb5SH8hXiag8R4F77G/fbbVjAxONWB1jBfOep YPJw1gC5boKxByUWwCNbWdUzLMO4eU4DJPZyQTCYkQcM7JwMNsfpBjJaxz4S2wHiJyNh ysTQ== X-Gm-Message-State: AOAM531BjBYurOMkQXPBMmDxak6hlsMUJgw35sqqLtPE63UWL96vl9jj l4ywVd3pfu69ozV6vTMMHRAEKp+DNI8= X-Google-Smtp-Source: ABdhPJwj4rHidVuSerO73p+MgC4zPGIOlGhlmT9p6UEZnOURmS83LLMcFaC8wfCWoMIXuuPy00r2yP97Z9w= X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:90:200:4c72:89be:dba3:2bcb]) (user=seanjc job=sendgmr) by 2002:a05:6214:1321:: with SMTP id c1mr5005905qvv.43.1632531352819; Fri, 24 Sep 2021 17:55:52 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 24 Sep 2021 17:55:24 -0700 In-Reply-To: <20210925005528.1145584-1-seanjc@google.com> Message-Id: <20210925005528.1145584-11-seanjc@google.com> Mime-Version: 1.0 References: <20210925005528.1145584-1-seanjc@google.com> X-Mailer: git-send-email 2.33.0.685.g46640cef36-goog Subject: [PATCH 10/14] KVM: Split out a kvm_vcpu_block() helper from kvm_vcpu_halt() From: Sean Christopherson To: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Paul Mackerras , Christian Borntraeger , Janosch Frank , Paolo Bonzini Cc: James Morse , Alexandru Elisei , Suzuki K Poulose , 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, linux-kernel@vger.kernel.org, David Matlack , 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. Signed-off-by: Sean Christopherson Reviewed-by: Christian Borntraeger Reviewed-by: David Matlack --- include/linux/kvm_host.h | 1 + virt/kvm/kvm_main.c | 50 ++++++++++++++++++++++++++++------------ 2 files changed, 36 insertions(+), 15 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index d2a8be3fb9ba..655c2b24db2d 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -966,6 +966,7 @@ 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 280cf1dca7db..fe34457530c2 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -3199,6 +3199,34 @@ 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) +{ + bool waited = false; + + kvm_arch_vcpu_blocking(vcpu); + + prepare_to_rcuwait(&vcpu->wait); + for (;;) { + set_current_state(TASK_INTERRUPTIBLE); + + if (kvm_vcpu_check_block(vcpu) < 0) + break; + + waited = true; + schedule(); + } + finish_rcuwait(&vcpu->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) { @@ -3221,6 +3249,12 @@ 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) { bool halt_poll_allowed = !kvm_arch_no_poll(vcpu); @@ -3245,21 +3279,7 @@ void kvm_vcpu_halt(struct kvm_vcpu *vcpu) } while (kvm_vcpu_can_poll(cur, stop)); } - kvm_arch_vcpu_blocking(vcpu); - - prepare_to_rcuwait(&vcpu->wait); - for (;;) { - set_current_state(TASK_INTERRUPTIBLE); - - if (kvm_vcpu_check_block(vcpu) < 0) - break; - - waited = true; - schedule(); - } - finish_rcuwait(&vcpu->wait); - - kvm_arch_vcpu_unblocking(vcpu); + waited = kvm_vcpu_block(vcpu); cur = ktime_get(); if (waited) {