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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 7CDB0C43441 for ; Mon, 12 Nov 2018 10:09:02 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 EC570216FD for ; Mon, 12 Nov 2018 10:09:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EC570216FD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 42tmgb71lMzF38H for ; Mon, 12 Nov 2018 21:08:59 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=linux.ibm.com (client-ip=148.163.156.1; helo=mx0a-001b2d01.pphosted.com; envelope-from=bharata@linux.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 42tmdb3wkmzF3G3 for ; Mon, 12 Nov 2018 21:07:15 +1100 (AEDT) Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wACA4NI8129153 for ; Mon, 12 Nov 2018 05:07:13 -0500 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0a-001b2d01.pphosted.com with ESMTP id 2nq51neamt-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 12 Nov 2018 05:07:12 -0500 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 12 Nov 2018 10:07:07 -0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id wACA76RF7733512 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 12 Nov 2018 10:07:06 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0704811C04C; Mon, 12 Nov 2018 10:07:06 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5E4B211C054; Mon, 12 Nov 2018 10:07:04 +0000 (GMT) Received: from in.ibm.com (unknown [9.199.50.113]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Mon, 12 Nov 2018 10:07:04 +0000 (GMT) Date: Mon, 12 Nov 2018 15:37:02 +0530 From: Bharata B Rao To: Balbir Singh Subject: Re: [RFC PATCH v1 2/4] kvmppc: Add support for shared pages in HMM driver References: <20181022051837.1165-1-bharata@linux.ibm.com> <20181022051837.1165-3-bharata@linux.ibm.com> <20181101104552.GE16399@350D> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181101104552.GE16399@350D> User-Agent: Mutt/1.10.1 (2018-07-13) X-TM-AS-GCONF: 00 x-cbid: 18111210-4275-0000-0000-000002DF9483 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18111210-4276-0000-0000-000037EC9EEF Message-Id: <20181112100702.GF17399@in.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2018-11-12_08:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1811120093 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: bharata@linux.ibm.com Cc: linuxram@us.ibm.com, kvm-ppc@vger.kernel.org, benh@linux.ibm.com, linux-mm@kvack.org, jglisse@redhat.com, aneesh.kumar@linux.vnet.ibm.com, paulus@au1.ibm.com, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, Nov 01, 2018 at 09:45:52PM +1100, Balbir Singh wrote: > On Mon, Oct 22, 2018 at 10:48:35AM +0530, Bharata B Rao wrote: > > A secure guest will share some of its pages with hypervisor (Eg. virtio > > bounce buffers etc). Support shared pages in HMM driver. > > > > Signed-off-by: Bharata B Rao > > --- > > arch/powerpc/kvm/book3s_hv_hmm.c | 69 ++++++++++++++++++++++++++++++-- > > 1 file changed, 65 insertions(+), 4 deletions(-) > > > > diff --git a/arch/powerpc/kvm/book3s_hv_hmm.c b/arch/powerpc/kvm/book3s_hv_hmm.c > > index a2ee3163a312..09b8e19b7605 100644 > > --- a/arch/powerpc/kvm/book3s_hv_hmm.c > > +++ b/arch/powerpc/kvm/book3s_hv_hmm.c > > @@ -50,6 +50,7 @@ struct kvmppc_hmm_page_pvt { > > struct hlist_head *hmm_hash; > > unsigned int lpid; > > unsigned long gpa; > > + bool skip_page_out; > > }; > > > > struct kvmppc_hmm_migrate_args { > > @@ -278,6 +279,65 @@ static unsigned long kvmppc_gpa_to_hva(struct kvm *kvm, unsigned long gpa, > > return hva; > > } > > > > +/* > > + * Shares the page with HV, thus making it a normal page. > > + * > > + * - If the page is already secure, then provision a new page and share > > + * - If the page is a normal page, share the existing page > > + * > > + * In the former case, uses the HMM fault handler to release the HMM page. > > + */ > > +static unsigned long > > +kvmppc_share_page(struct kvm *kvm, unsigned long gpa, > > + unsigned long addr, unsigned long page_shift) > > +{ > > + > > So this is a special flag passed via the hypercall to say > this page can be skipped from page_out from secure memory? > Who has the master copy of the page at this point? > > In which case the question is > > Why did we get a fault on the page which resulted in the > fault migration ops being called? > What category of pages are considered shared? When UV/guest asks for sharing a page, there can be two cases: - If the page is already secure, then provision a new page and share - If the page is a normal page, share the existing page In the former case, we touch the page via get_user_pages() and re-use the HMM fault handler to release the HMM page. We use skip_page_out to mark that this page is meant to be released w/o doing a page-out which otherwise would be done if HV touches a secure page. When a page is shared, both HV and UV have mappings to the same physical page that resides in the non-secure memory. Regards, Bharata.