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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D747EC6FD1C for ; Fri, 24 Mar 2023 03:50:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231173AbjCXDub (ORCPT ); Thu, 23 Mar 2023 23:50:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230471AbjCXDu3 (ORCPT ); Thu, 23 Mar 2023 23:50:29 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A6EB51A97D for ; Thu, 23 Mar 2023 20:49:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1679629786; 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=tvUYLbQ5ItZ7YGhfcbwRlMUBJivNVLYqKMadR4fNk5g=; b=RG+1BLtWSqvPsEXgXopS7TorjGLwIVLn5+lxULrusXHJHKLdkVI/xmlesHXplbHvYm6wO5 0MQOu+j+szbJKwQgGN0tcabCMGLBMYcWQsgVHXV5oflabDNhipqMVOsvIyQ3dVi7hq/Cy+ hnhQ8QiSZd4n1X3AVq1kj5QJu60OR1s= Received: from mail-pj1-f72.google.com (mail-pj1-f72.google.com [209.85.216.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-177-Nk6WwrayOeSECkjcU7PykA-1; Thu, 23 Mar 2023 23:49:45 -0400 X-MC-Unique: Nk6WwrayOeSECkjcU7PykA-1 Received: by mail-pj1-f72.google.com with SMTP id m10-20020a17090a4d8a00b0023fa854ec76so1756532pjh.9 for ; Thu, 23 Mar 2023 20:49:45 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679629784; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=tvUYLbQ5ItZ7YGhfcbwRlMUBJivNVLYqKMadR4fNk5g=; b=koUYjrg/CBzwc3gc9Nl0shuo7MQ22K1XLX59wlLBTPMTsU/feW/DqWkwC1TGd24rEn CsqZLVdpNm21hj9yFIsAIYmzzgHXPWekz2n/cusX6Hs4vLvjBlSS45I2aMwQW91JXYft DV799H2QsKvvj3XW76n3wCZMkutOM8yV68df9OdXehqg3JRYwvzat4Fz8yVwIEVcSLFy EtY7be6j6ha3ivOUMNbBmSMWnA+IwBpFidMEGHhqeCMIBVxHzq3elGmJkn9Rkhio9q1Q 3EKQboF5cq83CPs9xGF/1mHGL61Fbn4XUF13oVx03nk5LDoTjI/f5fnbU74yqhxjSzfd NrPw== X-Gm-Message-State: AO0yUKViw2ekr8/kDxPXUSuYGapIrEEcRxKNhxqjDUE1tMWCNUuowlJq yQYeg60XAtRDJesuOCJcBP9lLGCrSUnVeaLJfPu60U4w/F6zwDN+AdKkY4Y5/2eWP95gh4KtrRT wkSUM41GB6kJociWqB5nFbAVI5AdjLQ== X-Received: by 2002:a05:6a20:131c:b0:d9:c0fe:17ca with SMTP id g28-20020a056a20131c00b000d9c0fe17camr1377711pzh.16.1679629784226; Thu, 23 Mar 2023 20:49:44 -0700 (PDT) X-Google-Smtp-Source: AK7set9jvo39PB6TeNlOHJ5XW5HW9YLQwg1N6J3rrirOctyXgU8nBNprbs5zVYrlhDXL7BhSRGvnhw== X-Received: by 2002:a05:6a20:131c:b0:d9:c0fe:17ca with SMTP id g28-20020a056a20131c00b000d9c0fe17camr1377695pzh.16.1679629783909; Thu, 23 Mar 2023 20:49:43 -0700 (PDT) Received: from [10.72.13.198] ([43.228.180.230]) by smtp.gmail.com with ESMTPSA id q8-20020a656848000000b005034a57b963sm12467895pgt.58.2023.03.23.20.49.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 23 Mar 2023 20:49:43 -0700 (PDT) Message-ID: <78c7511a-deab-7e95-fde1-5317a568cf97@redhat.com> Date: Fri, 24 Mar 2023 11:49:32 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [PATCH v3 8/8] vdpa_sim: add support for user VA Content-Language: en-US To: Stefano Garzarella , virtualization@lists.linux-foundation.org Cc: kvm@vger.kernel.org, stefanha@redhat.com, linux-kernel@vger.kernel.org, eperezma@redhat.com, "Michael S. Tsirkin" , Andrey Zhadchenko , netdev@vger.kernel.org References: <20230321154228.182769-1-sgarzare@redhat.com> <20230321154804.184577-1-sgarzare@redhat.com> <20230321154804.184577-4-sgarzare@redhat.com> From: Jason Wang In-Reply-To: <20230321154804.184577-4-sgarzare@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 在 2023/3/21 23:48, Stefano Garzarella 写道: > The new "use_va" module parameter (default: true) is used in > vdpa_alloc_device() to inform the vDPA framework that the device > supports VA. > > vringh is initialized to use VA only when "use_va" is true and the > user's mm has been bound. So, only when the bus supports user VA > (e.g. vhost-vdpa). > > vdpasim_mm_work_fn work is used to serialize the binding to a new > address space when the .bind_mm callback is invoked, and unbinding > when the .unbind_mm callback is invoked. > > Call mmget_not_zero()/kthread_use_mm() inside the worker function > to pin the address space only as long as needed, following the > documentation of mmget() in include/linux/sched/mm.h: > > * Never use this function to pin this address space for an > * unbounded/indefinite amount of time. > > Signed-off-by: Stefano Garzarella > --- > > Notes: > v3: > - called mmget_not_zero() before kthread_use_mm() [Jason] > As the documentation of mmget() in include/linux/sched/mm.h says: > > * Never use this function to pin this address space for an > * unbounded/indefinite amount of time. > > I moved mmget_not_zero/kthread_use_mm inside the worker function, > this way we pin the address space only as long as needed. > This is similar to what vfio_iommu_type1_dma_rw_chunk() does in > drivers/vfio/vfio_iommu_type1.c > - simplified the mm bind/unbind [Jason] > - renamed vdpasim_worker_change_mm_sync() [Jason] > - fix commit message (s/default: false/default: true) > v2: > - `use_va` set to true by default [Eugenio] > - supported the new unbind_mm callback [Jason] > - removed the unbind_mm call in vdpasim_do_reset() [Jason] > - avoided to release the lock while call kthread_flush_work() since we > are now using a mutex to protect the device state > > drivers/vdpa/vdpa_sim/vdpa_sim.h | 1 + > drivers/vdpa/vdpa_sim/vdpa_sim.c | 80 +++++++++++++++++++++++++++++++- > 2 files changed, 79 insertions(+), 2 deletions(-) > > diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h > index 4774292fba8c..3a42887d05d9 100644 > --- a/drivers/vdpa/vdpa_sim/vdpa_sim.h > +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h > @@ -59,6 +59,7 @@ struct vdpasim { > struct vdpasim_virtqueue *vqs; > struct kthread_worker *worker; > struct kthread_work work; > + struct mm_struct *mm_bound; > struct vdpasim_dev_attr dev_attr; > /* mutex to synchronize virtqueue state */ > struct mutex mutex; > diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c > index ab4cfb82c237..23c891cdcd54 100644 > --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c > +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c > @@ -35,10 +35,44 @@ module_param(max_iotlb_entries, int, 0444); > MODULE_PARM_DESC(max_iotlb_entries, > "Maximum number of iotlb entries for each address space. 0 means unlimited. (default: 2048)"); > > +static bool use_va = true; > +module_param(use_va, bool, 0444); > +MODULE_PARM_DESC(use_va, "Enable/disable the device's ability to use VA"); > + > #define VDPASIM_QUEUE_ALIGN PAGE_SIZE > #define VDPASIM_QUEUE_MAX 256 > #define VDPASIM_VENDOR_ID 0 > > +struct vdpasim_mm_work { > + struct kthread_work work; > + struct vdpasim *vdpasim; > + struct mm_struct *mm_to_bind; > + int ret; > +}; > + > +static void vdpasim_mm_work_fn(struct kthread_work *work) > +{ > + struct vdpasim_mm_work *mm_work = > + container_of(work, struct vdpasim_mm_work, work); > + struct vdpasim *vdpasim = mm_work->vdpasim; > + > + mm_work->ret = 0; > + > + //TODO: should we attach the cgroup of the mm owner? > + vdpasim->mm_bound = mm_work->mm_to_bind; > +} > + > +static void vdpasim_worker_change_mm_sync(struct vdpasim *vdpasim, > + struct vdpasim_mm_work *mm_work) > +{ > + struct kthread_work *work = &mm_work->work; > + > + kthread_init_work(work, vdpasim_mm_work_fn); > + kthread_queue_work(vdpasim->worker, work); > + > + kthread_flush_work(work); > +} > + > static struct vdpasim *vdpa_to_sim(struct vdpa_device *vdpa) > { > return container_of(vdpa, struct vdpasim, vdpa); > @@ -59,8 +93,10 @@ static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx) > { > struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx]; > uint16_t last_avail_idx = vq->vring.last_avail_idx; > + bool va_enabled = use_va && vdpasim->mm_bound; > > - vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true, false, > + vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true, > + va_enabled, > (struct vring_desc *)(uintptr_t)vq->desc_addr, > (struct vring_avail *) > (uintptr_t)vq->driver_addr, > @@ -130,8 +166,20 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops; > static void vdpasim_work_fn(struct kthread_work *work) > { > struct vdpasim *vdpasim = container_of(work, struct vdpasim, work); > + struct mm_struct *mm = vdpasim->mm_bound; > + > + if (mm) { > + if (!mmget_not_zero(mm)) > + return; Do we need to check use_va here. Other than this Acked-by: Jason Wang Thanks > + kthread_use_mm(mm); > + } > > vdpasim->dev_attr.work_fn(vdpasim); > + > + if (mm) { > + kthread_unuse_mm(mm); > + mmput(mm); > + } > } > > struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr, > @@ -162,7 +210,7 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr, > vdpa = __vdpa_alloc_device(NULL, ops, > dev_attr->ngroups, dev_attr->nas, > dev_attr->alloc_size, > - dev_attr->name, false); > + dev_attr->name, use_va); > if (IS_ERR(vdpa)) { > ret = PTR_ERR(vdpa); > goto err_alloc; > @@ -582,6 +630,30 @@ static int vdpasim_set_map(struct vdpa_device *vdpa, unsigned int asid, > return ret; > } > > +static int vdpasim_bind_mm(struct vdpa_device *vdpa, struct mm_struct *mm) > +{ > + struct vdpasim *vdpasim = vdpa_to_sim(vdpa); > + struct vdpasim_mm_work mm_work; > + > + mm_work.vdpasim = vdpasim; > + mm_work.mm_to_bind = mm; > + > + vdpasim_worker_change_mm_sync(vdpasim, &mm_work); > + > + return mm_work.ret; > +} > + > +static void vdpasim_unbind_mm(struct vdpa_device *vdpa) > +{ > + struct vdpasim *vdpasim = vdpa_to_sim(vdpa); > + struct vdpasim_mm_work mm_work; > + > + mm_work.vdpasim = vdpasim; > + mm_work.mm_to_bind = NULL; > + > + vdpasim_worker_change_mm_sync(vdpasim, &mm_work); > +} > + > static int vdpasim_dma_map(struct vdpa_device *vdpa, unsigned int asid, > u64 iova, u64 size, > u64 pa, u32 perm, void *opaque) > @@ -678,6 +750,8 @@ static const struct vdpa_config_ops vdpasim_config_ops = { > .set_group_asid = vdpasim_set_group_asid, > .dma_map = vdpasim_dma_map, > .dma_unmap = vdpasim_dma_unmap, > + .bind_mm = vdpasim_bind_mm, > + .unbind_mm = vdpasim_unbind_mm, > .free = vdpasim_free, > }; > > @@ -712,6 +786,8 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops = { > .get_iova_range = vdpasim_get_iova_range, > .set_group_asid = vdpasim_set_group_asid, > .set_map = vdpasim_set_map, > + .bind_mm = vdpasim_bind_mm, > + .unbind_mm = vdpasim_unbind_mm, > .free = vdpasim_free, > }; >