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=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 857EAC47089 for ; Thu, 27 May 2021 17:57:07 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 DF9706105A for ; Thu, 27 May 2021 17:57:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DF9706105A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59902 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lmKFk-0000vr-TS for qemu-devel@archiver.kernel.org; Thu, 27 May 2021 13:57:04 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60974) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lmKF0-00007A-H3 for qemu-devel@nongnu.org; Thu, 27 May 2021 13:56:18 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:57600) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lmKEx-00030D-GN for qemu-devel@nongnu.org; Thu, 27 May 2021 13:56:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1622138174; 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=eE8oOHqHefAi+FaryUy970J+QpT+8acfA+paTF9GUtw=; b=SIpzfkkSHai3xC25tEcJ/mxKhitPP0zwIZUz3BJBFk+ZjKQ5WWvY53YWz/VI9aRIfQZleh 4UJLCkvaSM7mbM42dpLQRlp163EbxEG0+foyQl8M2vY0jmtrnvZur6Tp4eAp++zuUQIwwN 0P4CRw8NH3oqQxmlKsG03qb6AaqTA+s= 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-333-NRk6BvNJNyK3fOl3yJjz5g-1; Thu, 27 May 2021 13:56:12 -0400 X-MC-Unique: NRk6BvNJNyK3fOl3yJjz5g-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 6804E803621; Thu, 27 May 2021 17:56:11 +0000 (UTC) Received: from work-vm (ovpn-114-249.ams2.redhat.com [10.36.114.249]) by smtp.corp.redhat.com (Postfix) with ESMTPS id ED1A860CC9; Thu, 27 May 2021 17:56:03 +0000 (UTC) Date: Thu, 27 May 2021 18:56:00 +0100 From: "Dr. David Alan Gilbert" To: Stefan Hajnoczi Subject: Re: [PATCH v3 20/26] DAX/unmap virtiofsd: Parse unmappable elements Message-ID: References: <20210428110100.27757-1-dgilbert@redhat.com> <20210428110100.27757-21-dgilbert@redhat.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/2.0.7 (2021-05-04) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.374, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: virtio-fs@redhat.com, qemu-devel@nongnu.org, vgoyal@redhat.com, groug@kaod.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Stefan Hajnoczi (stefanha@redhat.com) wrote: > On Wed, Apr 28, 2021 at 12:00:54PM +0100, Dr. David Alan Gilbert (git) wrote: > > From: "Dr. David Alan Gilbert" > > > > For some read/writes the virtio queue elements are unmappable by > > the daemon; these are cases where the data is to be read/written > > from non-RAM. In viritofs's case this is typically a direct read/write > > s/viritofs/virtiofs/ Eventually I'll stop making that typo. > > into an mmap'd DAX file also on virtiofs (possibly on another instance). > > > > When we receive a virtio queue element, check that we have enough > > mappable data to handle the headers. Make a note of the number of > > unmappable 'in' entries (ie. for read data back to the VMM), > > and flag the fuse_bufvec for 'out' entries with a new flag > > FUSE_BUF_PHYS_ADDR. > > > > Signed-off-by: Dr. David Alan Gilbert > > with fix by: > > Signed-off-by: Liu Bo > > --- > > tools/virtiofsd/buffer.c | 4 +- > > tools/virtiofsd/fuse_common.h | 7 ++ > > tools/virtiofsd/fuse_virtio.c | 230 ++++++++++++++++++++++++---------- > > 3 files changed, 173 insertions(+), 68 deletions(-) > > > > diff --git a/tools/virtiofsd/buffer.c b/tools/virtiofsd/buffer.c > > index 874f01c488..1a050aa441 100644 > > --- a/tools/virtiofsd/buffer.c > > +++ b/tools/virtiofsd/buffer.c > > @@ -77,6 +77,7 @@ static ssize_t fuse_buf_write(const struct fuse_buf *dst, size_t dst_off, > > ssize_t res = 0; > > size_t copied = 0; > > > > + assert(!(src->flags & FUSE_BUF_PHYS_ADDR)); > > while (len) { > > if (dst->flags & FUSE_BUF_FD_SEEK) { > > res = pwrite(dst->fd, (char *)src->mem + src_off, len, > > @@ -272,7 +273,8 @@ ssize_t fuse_buf_copy(struct fuse_bufvec *dstv, struct fuse_bufvec *srcv) > > * process > > */ > > for (i = 0; i < srcv->count; i++) { > > - if (srcv->buf[i].flags & FUSE_BUF_IS_FD) { > > + if ((srcv->buf[i].flags & FUSE_BUF_PHYS_ADDR) || > > + (srcv->buf[i].flags & FUSE_BUF_IS_FD)) { > > break; > > } > > } > > diff --git a/tools/virtiofsd/fuse_common.h b/tools/virtiofsd/fuse_common.h > > index fa9671872e..af43cf19f9 100644 > > --- a/tools/virtiofsd/fuse_common.h > > +++ b/tools/virtiofsd/fuse_common.h > > @@ -626,6 +626,13 @@ enum fuse_buf_flags { > > * detected. > > */ > > FUSE_BUF_FD_RETRY = (1 << 3), > > + > > + /** > > + * The addresses in the iovec represent guest physical addresses > > + * that can't be mapped by the daemon process. > > + * IO must be bounced back to the VMM to do it. > > + */ > > + FUSE_BUF_PHYS_ADDR = (1 << 4), > > Based on the previous patch this is not a gpa, it's an IOVA. Depending > on the virtiofs device's DMA address space in QEMU this might be the > same as guest physical addresses but there could also be vIOMMU > translation (see the address_space_translate() call in the patch that > implemented the IO slave command). I've changed that comment to: /** * The addresses in the iovec represent guest physical addresses * (or IOVA when used with an IOMMU) * that can't be mapped by the * daemon process. * IO must be bounced back to the VMM to do it. > Maybe virtiofs + vIOMMU has never been tested though... I'm not sure it > works today. It has and it definitely doesn't work yet. > If you want to leave it as is, feel free: > Reviewed-by: Stefan Hajnoczi Thanks. Dave -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK