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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A3BB8C0650F for ; Mon, 5 Aug 2019 07:14:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8111820B1F for ; Mon, 5 Aug 2019 07:14:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727485AbfHEHOs (ORCPT ); Mon, 5 Aug 2019 03:14:48 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:38980 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726587AbfHEHOs (ORCPT ); Mon, 5 Aug 2019 03:14:48 -0400 Received: by mail-wr1-f65.google.com with SMTP id x4so30069592wrt.6 for ; Mon, 05 Aug 2019 00:14:46 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:openpgp:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=xXNzFDoqWDF3bFjncF2L5fOVNU1OQ5j5piUBIWBmL0I=; b=efnObHL20oxxcYmlpLMKAVwYQCVkpxZZAT05Xs7eEHZ3YfQ4nHJnZJf3U5+g7Y/5jh +s4q5onnaxGJ+SILKl/tc1l6W/PfIaa0RiMyFIkp13r92L08y4KEB/QT0hABNNC3aPlH IzrHCTG+pW5iVhJVmB/WDZo7IHVReb9hkUa8DFfBxDekSqZjbSzgVsog5RHp85JU9QhL 5DhZG9kb6U51JSHklhIDyFdHk2I4yKNnsh1X4SzQD6jxou5rTTPmoUGfPb6dbliNYcQC hO1hh64CbP/E6kKTCNZD+XPMeHAtN1j8vPWShB5dKrnIpSgjuQN6mdAtjTuKCHSsWR4j dLVg== X-Gm-Message-State: APjAAAXvWwPmk9hOrMxugteFTHGDTr5abH7cpY2TwirX6+IgYxkJ9AYf Rx/RqTvs4+bzBNNMEP+BET2uvy+S7mk= X-Google-Smtp-Source: APXvYqx5xT03XMyZCDbDAzBfRBcUMD25ISn8anlFxox0BiwSgKaltwaTiYWfWbosNFrA3zbrZE2mOg== X-Received: by 2002:adf:eb49:: with SMTP id u9mr42305386wrn.215.1564989285989; Mon, 05 Aug 2019 00:14:45 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:4013:e920:9388:c3ff? ([2001:b07:6468:f312:4013:e920:9388:c3ff]) by smtp.gmail.com with ESMTPSA id g11sm79705061wrq.92.2019.08.05.00.14.44 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Mon, 05 Aug 2019 00:14:45 -0700 (PDT) Subject: Re: [RFC PATCH v2 10/19] RISC-V: KVM: Handle WFI exits for VCPU To: Anup Patel Cc: Anup Patel , Palmer Dabbelt , Paul Walmsley , Radim K , Daniel Lezcano , Thomas Gleixner , Atish Patra , Alistair Francis , Damien Le Moal , Christoph Hellwig , "kvm@vger.kernel.org" , "linux-riscv@lists.infradead.org" , "linux-kernel@vger.kernel.org" References: <20190802074620.115029-1-anup.patel@wdc.com> <20190802074620.115029-11-anup.patel@wdc.com> <5b966171-4d11-237d-5a43-dc881efb7d0a@redhat.com> From: Paolo Bonzini Openpgp: preference=signencrypt Message-ID: <458f6b85-cdb2-5e6b-6730-4875f0e4cdba@redhat.com> Date: Mon, 5 Aug 2019 09:14:44 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/08/19 09:12, Anup Patel wrote: > On Fri, Aug 2, 2019 at 2:33 PM Paolo Bonzini wrote: >> >> On 02/08/19 09:47, Anup Patel wrote: >>> + if (!kvm_riscv_vcpu_has_interrupt(vcpu)) { >> >> This can be kvm_arch_vcpu_runnable instead, since kvm_vcpu_block will >> check it anyway before sleeping. > > I think we can skip this check here because kvm_vcpu_block() is > checking it anyway. Agree ?? Yes, but it's quite a bit faster to do this outside the call. There's a bunch of setup before kvm_vcpu_block reaches that point, and it includes mfences too once you add srcu_read_unlock/lock here. Paolo