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=-6.9 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 autolearn=unavailable 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 5E267C433E0 for ; Thu, 21 May 2020 18:38:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 435D720738 for ; Thu, 21 May 2020 18:38:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gAwKnG+n" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729756AbgEUSij (ORCPT ); Thu, 21 May 2020 14:38:39 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:39383 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729726AbgEUSij (ORCPT ); Thu, 21 May 2020 14:38:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1590086318; 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=6xn++Cf4HTyCSbGYh8HNPobkxrKx2sAl2lxN9hs9ouI=; b=gAwKnG+nz8HdKvQts9dsB0Zrpfz4FyRMpy/oH7YrGLyGKf46RCxfEGanyA0I4UpC3BNMtl E0A5gf+H8PggEMbEhvIci8hkQSa8+1342zwh68jvIQNz59u3ciHFC8AMjLsNzHQEB255OM IBKfrw/WxCq4x6cuoeQ1OXgdQ/G60Qo= 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-103-5bnbrclkMYKsSWfsdSTzWw-1; Thu, 21 May 2020 14:38:35 -0400 X-MC-Unique: 5bnbrclkMYKsSWfsdSTzWw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EF6E6EC1B2; Thu, 21 May 2020 18:38:32 +0000 (UTC) Received: from horse.redhat.com (ovpn-116-233.rdu2.redhat.com [10.10.116.233]) by smtp.corp.redhat.com (Postfix) with ESMTP id 96E7212A4D; Thu, 21 May 2020 18:38:32 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id 0D80322036E; Thu, 21 May 2020 14:38:32 -0400 (EDT) Date: Thu, 21 May 2020 14:38:32 -0400 From: Vivek Goyal To: Vitaly Kuznetsov Cc: kvm@vger.kernel.org, x86@kernel.org, Paolo Bonzini , Andy Lutomirski , Thomas Gleixner , Borislav Petkov , "H. Peter Anvin" , Wanpeng Li , Sean Christopherson , Jim Mattson , Gavin Shan , Peter Zijlstra , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/8] KVM: x86: extend struct kvm_vcpu_pv_apf_data with token info Message-ID: <20200521183832.GB46035@redhat.com> References: <20200511164752.2158645-1-vkuznets@redhat.com> <20200511164752.2158645-3-vkuznets@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200511164752.2158645-3-vkuznets@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, May 11, 2020 at 06:47:46PM +0200, Vitaly Kuznetsov wrote: > Currently, APF mechanism relies on the #PF abuse where the token is being > passed through CR2. If we switch to using interrupts to deliver page-ready > notifications we need a different way to pass the data. Extent the existing > 'struct kvm_vcpu_pv_apf_data' with token information for page-ready > notifications. > > The newly introduced apf_put_user_ready() temporary puts both reason > and token information, this will be changed to put token only when we > switch to interrupt based notifications. > > Signed-off-by: Vitaly Kuznetsov > --- > arch/x86/include/uapi/asm/kvm_para.h | 3 ++- > arch/x86/kvm/x86.c | 17 +++++++++++++---- > 2 files changed, 15 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h > index 2a8e0b6b9805..e3602a1de136 100644 > --- a/arch/x86/include/uapi/asm/kvm_para.h > +++ b/arch/x86/include/uapi/asm/kvm_para.h > @@ -113,7 +113,8 @@ struct kvm_mmu_op_release_pt { > > struct kvm_vcpu_pv_apf_data { > __u32 reason; Hi Vitaly, Given we are redoing it, can we convert "reason" into a flag instead and use bit 0 for signalling "page not present" Then rest of the 31 bits can be used for other purposes. I potentially want to use one bit to signal error (if it is known at the time of injecting #PF). > - __u8 pad[60]; > + __u32 pageready_token; > + __u8 pad[56]; Given token is 32 bit, for returning error in "page ready" type messages, I will probably use padding bytes and create pagready_flag and use one of the bits to signal error. Thanks Vivek