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=-17.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 F1447C433DB for ; Mon, 1 Feb 2021 06:33:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B1B7A64E31 for ; Mon, 1 Feb 2021 06:33:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231599AbhBAGao (ORCPT ); Mon, 1 Feb 2021 01:30:44 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:41815 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231790AbhBAGFV (ORCPT ); Mon, 1 Feb 2021 01:05:21 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612159434; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=d640g0AhW4H0p1MPXlNtTw79RpilHCze4Mi87EihdeA=; b=JQ30XCia6RQN8/WsIBXUO/KhL39MLQQ+fWEwQZwFM2EUrivKnHS+Z9FY1cqN+yhc6hiljk 4JgI6RqVF+Io6TiLuXSve8XtBQgPWkzunihs8grI4RQFgRmDKi7ncrDr+C4PByjnL4t5M8 KqsGwhwCBL+2iRNw67bZZm9Tl90GIO0= 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-174-ic3WixtZMn-kEXpG8WCikA-1; Mon, 01 Feb 2021 01:03:52 -0500 X-MC-Unique: ic3WixtZMn-kEXpG8WCikA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4E5C8801817; Mon, 1 Feb 2021 06:03:50 +0000 (UTC) Received: from [10.72.13.120] (ovpn-13-120.pek2.redhat.com [10.72.13.120]) by smtp.corp.redhat.com (Postfix) with ESMTP id D1C775D9DC; Mon, 1 Feb 2021 06:03:40 +0000 (UTC) Subject: Re: [PATCH RFC v2 09/10] vdpa_sim_blk: implement ramdisk behaviour To: Stefano Garzarella , virtualization@lists.linux-foundation.org Cc: Xie Yongji , "Michael S. Tsirkin" , Laurent Vivier , Stefan Hajnoczi , linux-kernel@vger.kernel.org, Max Gurtovoy , kvm@vger.kernel.org References: <20210128144127.113245-1-sgarzare@redhat.com> <20210128144127.113245-10-sgarzare@redhat.com> From: Jason Wang Message-ID: <7084ff0d-6dd3-66bc-1c34-4f9f99970d97@redhat.com> Date: Mon, 1 Feb 2021 14:03:39 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210128144127.113245-10-sgarzare@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/1/28 下午10:41, Stefano Garzarella wrote: > The previous implementation wrote only the status of each request. > This patch implements a more accurate block device simulator, > providing a ramdisk-like behavior. > > Signed-off-by: Stefano Garzarella > --- > v2: > - used %zd %zx to print size_t and ssize_t variables in dev_err() > - removed unnecessary new line [Jason] > - moved VIRTIO_BLK_T_GET_ID in another patch [Jason] > - used push/pull instead of write/read terminology > - added vdpasim_blk_check_range() to avoid overflows [Stefan] > - use vdpasim*_to_cpu instead of le*_to_cpu > - used vringh_kiov_length() helper [Jason] Acked-by: Jason Wang > --- > drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 164 ++++++++++++++++++++++++--- > 1 file changed, 146 insertions(+), 18 deletions(-) > > diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c > index 999f9ca0b628..fc47e8320358 100644 > --- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c > +++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c > @@ -3,6 +3,7 @@ > * VDPA simulator for block device. > * > * Copyright (c) 2020, Mellanox Technologies. All rights reserved. > + * Copyright (c) 2021, Red Hat Inc. All rights reserved. > * > */ > > @@ -13,6 +14,7 @@ > #include > #include > #include > +#include > #include > > #include "vdpa_sim.h" > @@ -36,10 +38,151 @@ > > static struct vdpasim *vdpasim_blk_dev; > > +static bool vdpasim_blk_check_range(u64 start_sector, size_t range_size) > +{ > + u64 range_sectors = range_size >> SECTOR_SHIFT; > + > + if (range_size > VDPASIM_BLK_SIZE_MAX * VDPASIM_BLK_SEG_MAX) > + return false; > + > + if (start_sector > VDPASIM_BLK_CAPACITY) > + return false; > + > + if (range_sectors > VDPASIM_BLK_CAPACITY - start_sector) > + return false; > + > + return true; > +} > + > +/* Returns 'true' if the request is handled (with or without an I/O error) > + * and the status is correctly written in the last byte of the 'in iov', > + * 'false' otherwise. > + */ > +static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim, > + struct vdpasim_virtqueue *vq) > +{ > + size_t pushed = 0, to_pull, to_push; > + struct virtio_blk_outhdr hdr; > + ssize_t bytes; > + loff_t offset; > + u64 sector; > + u8 status; > + u32 type; > + int ret; > + > + ret = vringh_getdesc_iotlb(&vq->vring, &vq->out_iov, &vq->in_iov, > + &vq->head, GFP_ATOMIC); > + if (ret != 1) > + return false; > + > + if (vq->out_iov.used < 1 || vq->in_iov.used < 1) { > + dev_err(&vdpasim->vdpa.dev, "missing headers - out_iov: %u in_iov %u\n", > + vq->out_iov.used, vq->in_iov.used); > + return false; > + } > + > + if (vq->in_iov.iov[vq->in_iov.used - 1].iov_len < 1) { > + dev_err(&vdpasim->vdpa.dev, "request in header too short\n"); > + return false; > + } > + > + /* The last byte is the status and we checked if the last iov has > + * enough room for it. > + */ > + to_push = vringh_kiov_length(&vq->in_iov) - 1; > + > + to_pull = vringh_kiov_length(&vq->out_iov); > + > + bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov, &hdr, > + sizeof(hdr)); > + if (bytes != sizeof(hdr)) { > + dev_err(&vdpasim->vdpa.dev, "request out header too short\n"); > + return false; > + } > + > + to_pull -= bytes; > + > + type = vdpasim32_to_cpu(vdpasim, hdr.type); > + sector = vdpasim64_to_cpu(vdpasim, hdr.sector); > + offset = sector << SECTOR_SHIFT; > + status = VIRTIO_BLK_S_OK; > + > + switch (type) { > + case VIRTIO_BLK_T_IN: > + if (!vdpasim_blk_check_range(sector, to_push)) { > + dev_err(&vdpasim->vdpa.dev, > + "reading over the capacity - offset: 0x%llx len: 0x%zx\n", > + offset, to_push); > + status = VIRTIO_BLK_S_IOERR; > + break; > + } > + > + bytes = vringh_iov_push_iotlb(&vq->vring, &vq->in_iov, > + vdpasim->buffer + offset, > + to_push); > + if (bytes < 0) { > + dev_err(&vdpasim->vdpa.dev, > + "vringh_iov_push_iotlb() error: %zd offset: 0x%llx len: 0x%zx\n", > + bytes, offset, to_push); > + status = VIRTIO_BLK_S_IOERR; > + break; > + } > + > + pushed += bytes; > + break; > + > + case VIRTIO_BLK_T_OUT: > + if (!vdpasim_blk_check_range(sector, to_pull)) { > + dev_err(&vdpasim->vdpa.dev, > + "writing over the capacity - offset: 0x%llx len: 0x%zx\n", > + offset, to_pull); > + status = VIRTIO_BLK_S_IOERR; > + break; > + } > + > + bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov, > + vdpasim->buffer + offset, > + to_pull); > + if (bytes < 0) { > + dev_err(&vdpasim->vdpa.dev, > + "vringh_iov_pull_iotlb() error: %zd offset: 0x%llx len: 0x%zx\n", > + bytes, offset, to_pull); > + status = VIRTIO_BLK_S_IOERR; > + break; > + } > + break; > + > + default: > + dev_warn(&vdpasim->vdpa.dev, > + "Unsupported request type %d\n", type); > + status = VIRTIO_BLK_S_IOERR; > + break; > + } > + > + /* If some operations fail, we need to skip the remaining bytes > + * to put the status in the last byte > + */ > + if (to_push - pushed > 0) > + vringh_kiov_advance(&vq->in_iov, to_push - pushed); > + > + /* Last byte is the status */ > + bytes = vringh_iov_push_iotlb(&vq->vring, &vq->in_iov, &status, 1); > + if (bytes != 1) > + return false; > + > + pushed += bytes; > + > + /* Make sure data is wrote before advancing index */ > + smp_wmb(); > + > + vringh_complete_iotlb(&vq->vring, vq->head, pushed); > + > + return true; > +} > + > static void vdpasim_blk_work(struct work_struct *work) > { > struct vdpasim *vdpasim = container_of(work, struct vdpasim, work); > - u8 status = VIRTIO_BLK_S_OK; > int i; > > spin_lock(&vdpasim->lock); > @@ -53,22 +196,7 @@ static void vdpasim_blk_work(struct work_struct *work) > if (!vq->ready) > continue; > > - while (vringh_getdesc_iotlb(&vq->vring, &vq->out_iov, > - &vq->in_iov, &vq->head, > - GFP_ATOMIC) > 0) { > - int write; > - > - vq->in_iov.i = vq->in_iov.used - 1; > - write = vringh_iov_push_iotlb(&vq->vring, &vq->in_iov, > - &status, 1); > - if (write <= 0) > - break; > - > - /* Make sure data is wrote before advancing index */ > - smp_wmb(); > - > - vringh_complete_iotlb(&vq->vring, vq->head, write); > - > + while (vdpasim_blk_handle_req(vdpasim, vq)) { > /* Make sure used is visible before rasing the interrupt. */ > smp_wmb(); > > @@ -109,7 +237,7 @@ static int __init vdpasim_blk_init(void) > dev_attr.config_size = sizeof(struct virtio_blk_config); > dev_attr.get_config = vdpasim_blk_get_config; > dev_attr.work_fn = vdpasim_blk_work; > - dev_attr.buffer_size = PAGE_SIZE; > + dev_attr.buffer_size = VDPASIM_BLK_CAPACITY << SECTOR_SHIFT; > > vdpasim_blk_dev = vdpasim_create(&dev_attr); > if (IS_ERR(vdpasim_blk_dev)) {