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=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 E9CBAC2BB85 for ; Thu, 16 Apr 2020 15:59:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CA634217D8 for ; Thu, 16 Apr 2020 15:59:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Zlr45w+C" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2897248AbgDPP7P (ORCPT ); Thu, 16 Apr 2020 11:59:15 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:44261 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2896263AbgDPP7G (ORCPT ); Thu, 16 Apr 2020 11:59:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1587052744; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=EN/H+dURYVmdO4EXHtSzJA+fcODs32+NBiRjW8BRIZw=; b=Zlr45w+CuG4go0NRRvN4Vf9xqmZh55ctTuS0egCxmfVFU8k7iYt+is5QOyf6ls0QDsSMSN oncKAAMPrBCWjZf/KUCkyq22Huemi/wmQxzNJw/TSq34K/G3GNBIAPu8S0ETN5ZAzwgDOe bBYrdypxtGOyN31VLZINn/rJwx0YAuQ= Received: from mail-qt1-f200.google.com (mail-qt1-f200.google.com [209.85.160.200]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-500-mUZs85VYM9a1XAM7kBrTKQ-1; Thu, 16 Apr 2020 11:59:02 -0400 X-MC-Unique: mUZs85VYM9a1XAM7kBrTKQ-1 Received: by mail-qt1-f200.google.com with SMTP id x56so19556925qtc.10 for ; Thu, 16 Apr 2020 08:59:02 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=EN/H+dURYVmdO4EXHtSzJA+fcODs32+NBiRjW8BRIZw=; b=SVg4qT5KW8EWZmUn488J0tRs3jXypJsfFKxfKEpEcCXhb5bDkLGyGjk3u63134xTH8 GEAsg9rKgEnyFezyPWa81YVHHNOWE+8tqCamERnb+/g3QDYm90/W1w6TXYxxRq9aFVFv dKEPIGQd9YnZ1ybBvtjfC4/43VCnewbyCx8kz3+AnUIdh5vQB6jn+2wVznjPADnjChK1 OBWKHi/qDfZugsw9QZyot3UA1DLuoJ0hawxPBX2+HkDjavUi9/4UQ1U/3P39InV4da4d hRO/ada2/H3P+dhqmJH6upy6eIAsQlzOrTg9tVpBfXPlf23v2a5xLZ0ZvvdtFvrpMNNS fwzg== X-Gm-Message-State: AGi0PuZ9/xhO6LxvyKP3EJxfG6oSuIzYDAlhkoUGp4m0UFAr1PPsFybN UomCwrOP4PPdSKnMOhlpBRsm35QLcHOb6c6NVEQ4a8cZ0xcXhr3SjwBXYs+NWkhHmYU2ZyP0bzy 56FkM0mcqbAak X-Received: by 2002:ad4:54c3:: with SMTP id j3mr10822714qvx.241.1587052741879; Thu, 16 Apr 2020 08:59:01 -0700 (PDT) X-Google-Smtp-Source: APiQypLDBUNGHmlOG11XrkWQ/pjAZwIDGioryxCRlW/eA5eQmopOir38iknIpUxnuvqlVuyvruM8dw== X-Received: by 2002:ad4:54c3:: with SMTP id j3mr10822694qvx.241.1587052741558; Thu, 16 Apr 2020 08:59:01 -0700 (PDT) Received: from xz-x1.redhat.com ([2607:9880:19c0:32::2]) by smtp.gmail.com with ESMTPSA id h13sm14752239qkj.21.2020.04.16.08.58.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Apr 2020 08:59:00 -0700 (PDT) From: Peter Xu To: kvm@vger.kernel.org Cc: Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , peterx@redhat.com Subject: [PATCH] KVM: X86: Force ASYNC_PF_PER_VCPU to be power of two Date: Thu, 16 Apr 2020 11:58:59 -0400 Message-Id: <20200416155859.267366-1-peterx@redhat.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Forcing the ASYNC_PF_PER_VCPU to be power of two is much easier to be used rather than calling roundup_pow_of_two() from time to time. Do this by adding a BUILD_BUG_ON() inside the hash function. Another point is that generally async pf does not allow concurrency over ASYNC_PF_PER_VCPU after all (see kvm_setup_async_pf()), so it does not make much sense either to have it not a power of two or some of the entries will definitely be wasted. Signed-off-by: Peter Xu --- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/x86.c | 8 +++++--- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 42a2d0d3984a..9f0fdaacdfa5 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -761,7 +761,7 @@ struct kvm_vcpu_arch { struct { bool halted; - gfn_t gfns[roundup_pow_of_two(ASYNC_PF_PER_VCPU)]; + gfn_t gfns[ASYNC_PF_PER_VCPU]; struct gfn_to_hva_cache data; u64 msr_val; u32 id; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b8124b562dea..fc74dafa72ff 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -261,7 +261,7 @@ static int emulator_fix_hypercall(struct x86_emulate_ctxt *ctxt); static inline void kvm_async_pf_hash_reset(struct kvm_vcpu *vcpu) { int i; - for (i = 0; i < roundup_pow_of_two(ASYNC_PF_PER_VCPU); i++) + for (i = 0; i < ASYNC_PF_PER_VCPU; i++) vcpu->arch.apf.gfns[i] = ~0; } @@ -10265,12 +10265,14 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work) static inline u32 kvm_async_pf_hash_fn(gfn_t gfn) { + BUILD_BUG_ON(!is_power_of_2(ASYNC_PF_PER_VCPU)); + return hash_32(gfn & 0xffffffff, order_base_2(ASYNC_PF_PER_VCPU)); } static inline u32 kvm_async_pf_next_probe(u32 key) { - return (key + 1) & (roundup_pow_of_two(ASYNC_PF_PER_VCPU) - 1); + return (key + 1) & (ASYNC_PF_PER_VCPU - 1); } static void kvm_add_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn) @@ -10288,7 +10290,7 @@ static u32 kvm_async_pf_gfn_slot(struct kvm_vcpu *vcpu, gfn_t gfn) int i; u32 key = kvm_async_pf_hash_fn(gfn); - for (i = 0; i < roundup_pow_of_two(ASYNC_PF_PER_VCPU) && + for (i = 0; i < ASYNC_PF_PER_VCPU && (vcpu->arch.apf.gfns[key] != gfn && vcpu->arch.apf.gfns[key] != ~0); i++) key = kvm_async_pf_next_probe(key); -- 2.24.1