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=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 876A4C433E6 for ; Mon, 20 Jul 2020 17:49:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6888720709 for ; Mon, 20 Jul 2020 17:49:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="g08pY9C+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388142AbgGTRt0 (ORCPT ); Mon, 20 Jul 2020 13:49:26 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:24815 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726699AbgGTRtZ (ORCPT ); Mon, 20 Jul 2020 13:49:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595267363; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=4JlHwh3SUGPYylkGk+T5UD+lE4YPhqSmyAUTHmFlqd8=; b=g08pY9C+DMl0Km+42JFhsZqUK0VvUqJjnytsrhzSEyxHH34RFK6H0y2CBs0r7YodfPcM/V 2p2HEE5Qyi4U9pt5Wc+64L84m99GITQbalMXrBq1q9cpTLRAVvstv11TKGEVc/2s172dfI PQCtKRLuAj+sTtbS7ubgppJWWf2ijl0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-285-n5KZeqc4Obeqjrl-ozYV4w-1; Mon, 20 Jul 2020 13:49:21 -0400 X-MC-Unique: n5KZeqc4Obeqjrl-ozYV4w-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 88814800468; Mon, 20 Jul 2020 17:49:20 +0000 (UTC) Received: from horse.redhat.com (ovpn-115-128.rdu2.redhat.com [10.10.115.128]) by smtp.corp.redhat.com (Postfix) with ESMTP id A77F860E3E; Mon, 20 Jul 2020 17:49:17 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id 08429220203; Mon, 20 Jul 2020 13:49:17 -0400 (EDT) Date: Mon, 20 Jul 2020 13:49:16 -0400 From: Vivek Goyal To: Vitaly Kuznetsov Cc: virtio-fs-list , pbonzini@redhat.com, sean.j.christopherson@intel.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] kvm,x86: Exit to user space in case of page fault error Message-ID: <20200720174916.GE502563@redhat.com> References: <20200709125442.GA150543@redhat.com> <87365qsb2v.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87365qsb2v.fsf@vitty.brq.redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 17, 2020 at 12:14:00PM +0200, Vitaly Kuznetsov wrote: [..] > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > > index 6d6a0ae7800c..a0e6283e872d 100644 > > --- a/arch/x86/kvm/mmu/mmu.c > > +++ b/arch/x86/kvm/mmu/mmu.c > > @@ -4078,7 +4078,7 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn, > > if (!async) > > return false; /* *pfn has correct page already */ > > > > - if (!prefault && kvm_can_do_async_pf(vcpu)) { > > + if (!prefault && kvm_can_do_async_pf(vcpu, cr2_or_gpa >> PAGE_SHIFT)) { > > gpa_to_gfn() ? Will do. I forgot to make this change since last feedback. > > > trace_kvm_try_async_get_page(cr2_or_gpa, gfn); > > if (kvm_find_async_pf_gfn(vcpu, gfn)) { > > trace_kvm_async_pf_doublefault(cr2_or_gpa, gfn); > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index 88c593f83b28..c4d4dab3ccde 100644 > > --- a/arch/x86/kvm/x86.c > > +++ b/arch/x86/kvm/x86.c > > @@ -263,6 +263,13 @@ static inline void kvm_async_pf_hash_reset(struct kvm_vcpu *vcpu) > > vcpu->arch.apf.gfns[i] = ~0; > > } > > > > +static inline void kvm_error_gfn_hash_reset(struct kvm_vcpu *vcpu) > > +{ > > + int i; > > + for (i = 0; i < ERROR_GFN_PER_VCPU; i++) > > + vcpu->arch.apf.error_gfns[i] = ~0; > > Nit: I see this is already present in kvm_async_pf_hash_reset() but what > about defining > > diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h > index a7580f69dda0..9144fde2550e 100644 > --- a/include/linux/kvm_types.h > +++ b/include/linux/kvm_types.h > @@ -38,6 +38,7 @@ typedef u64 gpa_t; > typedef u64 gfn_t; > > #define GPA_INVALID (~(gpa_t)0) > +#define GFN_INVALID (~(gfn_t)0) Will do. [..] > > +static void kvm_del_error_gfn(struct kvm_vcpu *vcpu, gfn_t gfn) > > +{ > > + u32 key = kvm_error_gfn_hash_fn(gfn); > > + > > + if (WARN_ON_ONCE(vcpu->arch.apf.error_gfns[key] != gfn)) > > + return; > > + > > + vcpu->arch.apf.error_gfns[key] = ~0; > > +} > > + > > +static bool kvm_find_error_gfn(struct kvm_vcpu *vcpu, gfn_t gfn) > > +{ > > + u32 key = kvm_error_gfn_hash_fn(gfn); > > + > > + return vcpu->arch.apf.error_gfns[key] == gfn; > > +} > > These two functions kvm_del_error_gfn()/kvm_find_error_gfn() come in > pair and the only usage seems to be > > if (kvm_find_error_gfn()) > kvm_del_error_gfn(); > > what if we replace it with a single kvm_find_and_remove_error_gfn() and > drop the WARN_ON_ONCE()? Ok, I am fine with this as well. Will do. Thanks Vivek