From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Matlack Date: Tue, 28 Sep 2021 22:14:54 +0000 Subject: Re: [PATCH 14/14] KVM: x86: Invoke kvm_vcpu_block() directly for non-HALTED wait states Message-Id: List-Id: References: <20210925005528.1145584-1-seanjc@google.com> <20210925005528.1145584-15-seanjc@google.com> In-Reply-To: <20210925005528.1145584-15-seanjc@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Sean Christopherson Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Paul Mackerras , Christian Borntraeger , Janosch Frank , Paolo Bonzini , James Morse , Alexandru Elisei , Suzuki K Poulose , David Hildenbrand , Cornelia Huck , Claudio Imbrenda , 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, Jing Zhang On Fri, Sep 24, 2021 at 05:55:28PM -0700, Sean Christopherson wrote: > 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 Reviewed-by: David Matlack > --- > 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 > From mboxrd@z Thu Jan 1 00:00:00 1970 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 30488C4332F for ; Wed, 29 Sep 2021 07:12:52 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id D55B66137A for ; Wed, 29 Sep 2021 07:12:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org D55B66137A Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 85D594B104; Wed, 29 Sep 2021 03:12:51 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@google.com Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id CdUP2+XU93Ik; Wed, 29 Sep 2021 03:12:50 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 41A424B168; Wed, 29 Sep 2021 03:12:42 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id B63804057F for ; Tue, 28 Sep 2021 18:15:00 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id yq9jGgNkqx1q for ; Tue, 28 Sep 2021 18:14:59 -0400 (EDT) Received: from mail-pg1-f171.google.com (mail-pg1-f171.google.com [209.85.215.171]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id A3E724031F for ; Tue, 28 Sep 2021 18:14:59 -0400 (EDT) Received: by mail-pg1-f171.google.com with SMTP id g184so545401pgc.6 for ; Tue, 28 Sep 2021 15:14:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=oDTEp4uXq7wouuQuWuPnWVQXCIo6P8LpvQajseAha48=; b=BnufAkDaSqbvE0tuVagV8WXp+XHOA8rRfAQGH7v7vq47FtDaVwPb2gV3pg84col7Jn wiWxSJtOhRHOZ1OnBfK1IusCBeqHNprdHmkCTk9hwy1TjpFLJ2o37qhbCK64RU58wR+/ NVNuIOjncjEgaNz1Aji8RAKlyT10kUNAthNYDNVDkepM7EAAeST1QgAUJgZz9JV6W8pQ Ga3dyZRVb1TCTPcNFYt7tNYB7fChJLmzpTPIY1149VIXRC09i0vUfJF6BV+ql+c0RWWW CLk/XS24h5X+HgfBHwpw+x6pOo0ByCwKeOnP2OHqWK6fByzx9dwNkhyWHGw0eQ1hWxHI bubg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=oDTEp4uXq7wouuQuWuPnWVQXCIo6P8LpvQajseAha48=; b=6jZVPd33LSUu10e/XGZx0EohYlPwK/PRmcjnd3XCGCMwzS7tMB51j179RReFZzNHeh N4kFB6s7t2pcqL9VvJkAfMWK0/2PhQDrZEZ0ZXsRWf/Ft2AsE98qyyfy9ygNwsO3dSQx N1iK8BLNMl3fWZEqf8yfTaZ2Cp7t28Llau38KvETfUn7eKmRyg6grdg0Uh0E3kjfN1dX mvByf2H6QgEwQoa5Ldo292rwmfDRz/yAcRqhLJlaI2rfGUq4Zojdcbm58FclpIV4YDDW 4D+Bb/EKU4ezfOKtfB1aXPynhxDoCRaaFh/i0X8kNKSs5dbnvxoBBPuJpWzDcY5Id/St PuHw== X-Gm-Message-State: AOAM530mmSL2u9WIMB0p5Ve1u6ca8E7u/NegUYONT2t2T071mdidxUwj rj2jOBS2YPd8MiuHAm/WHdSuTA== X-Google-Smtp-Source: ABdhPJxBJllV/6MHwH/O4bupLMykTY/L8aml4vOWRLyRzjZbQcPh2xbpVAvFMm0QwWZGt6UvJ4KliA== X-Received: by 2002:a62:dd0a:0:b0:44b:bd85:9387 with SMTP id w10-20020a62dd0a000000b0044bbd859387mr2015835pff.49.1632867298411; Tue, 28 Sep 2021 15:14:58 -0700 (PDT) Received: from google.com (254.80.82.34.bc.googleusercontent.com. [34.82.80.254]) by smtp.gmail.com with ESMTPSA id d7sm142548pfq.43.2021.09.28.15.14.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Sep 2021 15:14:57 -0700 (PDT) Date: Tue, 28 Sep 2021 22:14:54 +0000 From: David Matlack To: Sean Christopherson Subject: Re: [PATCH 14/14] KVM: x86: Invoke kvm_vcpu_block() directly for non-HALTED wait states Message-ID: References: <20210925005528.1145584-1-seanjc@google.com> <20210925005528.1145584-15-seanjc@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210925005528.1145584-15-seanjc@google.com> X-Mailman-Approved-At: Wed, 29 Sep 2021 03:12:40 -0400 Cc: Wanpeng Li , kvm@vger.kernel.org, David Hildenbrand , linux-kernel@vger.kernel.org, Paul Mackerras , Claudio Imbrenda , kvmarm@lists.cs.columbia.edu, Janosch Frank , Marc Zyngier , Joerg Roedel , Huacai Chen , Christian Borntraeger , Aleksandar Markovic , kvm-ppc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Jim Mattson , Cornelia Huck , linux-mips@vger.kernel.org, Paolo Bonzini , Vitaly Kuznetsov X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Fri, Sep 24, 2021 at 05:55:28PM -0700, Sean Christopherson wrote: > 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 Reviewed-by: David Matlack > --- > 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 > _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm From mboxrd@z Thu Jan 1 00:00:00 1970 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 33027C433EF for ; Tue, 28 Sep 2021 22:15:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E8976138B for ; Tue, 28 Sep 2021 22:15:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243068AbhI1WQk (ORCPT ); Tue, 28 Sep 2021 18:16:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48182 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243079AbhI1WQj (ORCPT ); Tue, 28 Sep 2021 18:16:39 -0400 Received: from mail-pf1-x431.google.com (mail-pf1-x431.google.com [IPv6:2607:f8b0:4864:20::431]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 57616C061755 for ; Tue, 28 Sep 2021 15:14:59 -0700 (PDT) Received: by mail-pf1-x431.google.com with SMTP id q23so206540pfs.9 for ; Tue, 28 Sep 2021 15:14:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=oDTEp4uXq7wouuQuWuPnWVQXCIo6P8LpvQajseAha48=; b=BnufAkDaSqbvE0tuVagV8WXp+XHOA8rRfAQGH7v7vq47FtDaVwPb2gV3pg84col7Jn wiWxSJtOhRHOZ1OnBfK1IusCBeqHNprdHmkCTk9hwy1TjpFLJ2o37qhbCK64RU58wR+/ NVNuIOjncjEgaNz1Aji8RAKlyT10kUNAthNYDNVDkepM7EAAeST1QgAUJgZz9JV6W8pQ Ga3dyZRVb1TCTPcNFYt7tNYB7fChJLmzpTPIY1149VIXRC09i0vUfJF6BV+ql+c0RWWW CLk/XS24h5X+HgfBHwpw+x6pOo0ByCwKeOnP2OHqWK6fByzx9dwNkhyWHGw0eQ1hWxHI bubg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=oDTEp4uXq7wouuQuWuPnWVQXCIo6P8LpvQajseAha48=; b=qBDzInoABtO5rKj0r0DdbjeL9wnBWMHwAGf9vl7NmEJV9mJkbdt1e2xEgzCYTc76hb YmfSAm82YQ5Oq+tnt4Q/vCRNxYostW+QixOQPIq4gp5X2evSPB4bNLghGI2zetXc/Ubb nKW1OloPm2PyQwM26juLRyLnpSkAoUgRvSFkcrAbY0Pgx+BV6VrkwWtlGX4I+oOVb89G 3vUE9neot+XJs1nHFC0vc+2JlHQgi7Nf3MqoG5j5FM8A33gjb394nSNh8bExqbs8zvks dkU5+we/CR0EyRQBVX0N7DcbrgMyHbO4SgDzK+xE1d51WWxXro4eC8+gUlYZntbAJfyW Hl3Q== X-Gm-Message-State: AOAM531//BhYSlTosgdgCxzBi893uLM+hrS48cyUD64xiMykIuVgdw5u HnpkF5w4oWTO3B7n4xU0WoVYhg== X-Google-Smtp-Source: ABdhPJxBJllV/6MHwH/O4bupLMykTY/L8aml4vOWRLyRzjZbQcPh2xbpVAvFMm0QwWZGt6UvJ4KliA== X-Received: by 2002:a62:dd0a:0:b0:44b:bd85:9387 with SMTP id w10-20020a62dd0a000000b0044bbd859387mr2015835pff.49.1632867298411; Tue, 28 Sep 2021 15:14:58 -0700 (PDT) Received: from google.com (254.80.82.34.bc.googleusercontent.com. [34.82.80.254]) by smtp.gmail.com with ESMTPSA id d7sm142548pfq.43.2021.09.28.15.14.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Sep 2021 15:14:57 -0700 (PDT) Date: Tue, 28 Sep 2021 22:14:54 +0000 From: David Matlack To: Sean Christopherson Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Paul Mackerras , Christian Borntraeger , Janosch Frank , Paolo Bonzini , James Morse , Alexandru Elisei , Suzuki K Poulose , David Hildenbrand , Cornelia Huck , Claudio Imbrenda , 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, Jing Zhang Subject: Re: [PATCH 14/14] KVM: x86: Invoke kvm_vcpu_block() directly for non-HALTED wait states Message-ID: References: <20210925005528.1145584-1-seanjc@google.com> <20210925005528.1145584-15-seanjc@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210925005528.1145584-15-seanjc@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On Fri, Sep 24, 2021 at 05:55:28PM -0700, Sean Christopherson wrote: > 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 Reviewed-by: David Matlack > --- > 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 > From mboxrd@z Thu Jan 1 00:00:00 1970 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 E1320C433F5 for ; Tue, 28 Sep 2021 22:17:29 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B061E6134F for ; Tue, 28 Sep 2021 22:17:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org B061E6134F Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=AhMmhLg1wvogO73/uygYVXnzfL/rCovxmieJ0sf0ot4=; b=VWXabaGP9Vy0KG 2ZDNkZvPlyYxWuvq3sLYEH7UB0ZhtzSCS0otkScxlLGuH5zCnc+f9ReCbUzHRW5lru7TZBA1svaje 7j5+9ELuXbSbREDh7RY+OxpyQBLD9f7e22jkh7lXFpqGLF2HFeSu4b+vT+F7/wO6p5sCh2j7iFMAb MLH/G2SQKG6DqpaXhKK23CibyVIDqHUn2DHSY21brIKO73AR7dD1qyx1M24LSblCP6hQ8f+st9R6I bvVJEzXfb24aGyjpvRyp44w1nvM/iwNI3k2V9iePGV4qtaBIZG0owmf1gcc5E82iJpfVPq/tOW4hH cVNJUM2+eRe6hE/m3lGA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mVLNQ-008zv3-Qr; Tue, 28 Sep 2021 22:15:05 +0000 Received: from mail-pf1-x436.google.com ([2607:f8b0:4864:20::436]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mVLNM-008ztz-4R for linux-arm-kernel@lists.infradead.org; Tue, 28 Sep 2021 22:15:02 +0000 Received: by mail-pf1-x436.google.com with SMTP id u7so193119pfg.13 for ; Tue, 28 Sep 2021 15:14:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=oDTEp4uXq7wouuQuWuPnWVQXCIo6P8LpvQajseAha48=; b=BnufAkDaSqbvE0tuVagV8WXp+XHOA8rRfAQGH7v7vq47FtDaVwPb2gV3pg84col7Jn wiWxSJtOhRHOZ1OnBfK1IusCBeqHNprdHmkCTk9hwy1TjpFLJ2o37qhbCK64RU58wR+/ NVNuIOjncjEgaNz1Aji8RAKlyT10kUNAthNYDNVDkepM7EAAeST1QgAUJgZz9JV6W8pQ Ga3dyZRVb1TCTPcNFYt7tNYB7fChJLmzpTPIY1149VIXRC09i0vUfJF6BV+ql+c0RWWW CLk/XS24h5X+HgfBHwpw+x6pOo0ByCwKeOnP2OHqWK6fByzx9dwNkhyWHGw0eQ1hWxHI bubg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=oDTEp4uXq7wouuQuWuPnWVQXCIo6P8LpvQajseAha48=; b=BrpiK6AsJ4KMi18o0rzDIPshr8hLkIhocud1CUgS49xZAtp+YA6AwTLh8UnYqGUno7 VmCNWpyJrv7xMZhMqDYlRvkbsxgbkK1M1WvgGV0cjg1hWE6aNOdRnqQr7NuzxoOvN+CP mKFoG52SsnLc/0O/h4/UTK6n0nRaqJq4ZK1gqVETyqNDT7sG7nwWodN21DRtaggqCvAx cgx/QqW5Fx/N6wD2skziuL3sz3cWpkEBs5sCDR32NOXV4+8GVeZVzMqIW5Rl+2aq3NPI M004n+t16jg3hAJdXznLgq3CxyPw62KgROuND8OIAo4/Y/Zck4CpbvZH4+/A6ZsadEfh 7+6A== X-Gm-Message-State: AOAM530UnbSeJioLXycTZ/ePcUb5RPxaEERn74jbnyd0WpK4rOg1LiFe 1V0kDq2qI0NzTalhAsYJ5OCyEA== X-Google-Smtp-Source: ABdhPJxBJllV/6MHwH/O4bupLMykTY/L8aml4vOWRLyRzjZbQcPh2xbpVAvFMm0QwWZGt6UvJ4KliA== X-Received: by 2002:a62:dd0a:0:b0:44b:bd85:9387 with SMTP id w10-20020a62dd0a000000b0044bbd859387mr2015835pff.49.1632867298411; Tue, 28 Sep 2021 15:14:58 -0700 (PDT) Received: from google.com (254.80.82.34.bc.googleusercontent.com. [34.82.80.254]) by smtp.gmail.com with ESMTPSA id d7sm142548pfq.43.2021.09.28.15.14.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Sep 2021 15:14:57 -0700 (PDT) Date: Tue, 28 Sep 2021 22:14:54 +0000 From: David Matlack To: Sean Christopherson Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Paul Mackerras , Christian Borntraeger , Janosch Frank , Paolo Bonzini , James Morse , Alexandru Elisei , Suzuki K Poulose , David Hildenbrand , Cornelia Huck , Claudio Imbrenda , 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, Jing Zhang Subject: Re: [PATCH 14/14] KVM: x86: Invoke kvm_vcpu_block() directly for non-HALTED wait states Message-ID: References: <20210925005528.1145584-1-seanjc@google.com> <20210925005528.1145584-15-seanjc@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210925005528.1145584-15-seanjc@google.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210928_151500_230617_FA0A0220 X-CRM114-Status: GOOD ( 21.94 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Sep 24, 2021 at 05:55:28PM -0700, Sean Christopherson wrote: > 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 Reviewed-by: David Matlack > --- > 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 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel