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[209.132.180.67]) by mx.google.com with ESMTP id az5si18846003plb.111.2019.05.07.08.35.53; Tue, 07 May 2019 08:36:16 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-ext4-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@intel-com.20150623.gappssmtp.com header.s=20150623 header.b=TlGX4D84; spf=pass (google.com: best guess record for domain of linux-ext4-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-ext4-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726659AbfEGPfY (ORCPT + 99 others); Tue, 7 May 2019 11:35:24 -0400 Received: from mail-oi1-f194.google.com ([209.85.167.194]:41116 "EHLO mail-oi1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726545AbfEGPfY (ORCPT ); Tue, 7 May 2019 11:35:24 -0400 Received: by mail-oi1-f194.google.com with SMTP id b17so5477093oie.8 for ; Tue, 07 May 2019 08:35:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=pln9LT1uNdfaqhJNGD+O26m6HebQTGwT47fBp9Sl9RM=; b=TlGX4D8425HPlx+7p+S0uYa/l9Wse5Bk4e2arPdiSpjovqCqDcs+9LOYMOP6HfVzU0 TWixf7FReM5mQZFLKUId2NxKdlxa9AmTAx53KG06ByqkPKInRDkKj/naYzXM7aFtQOC5 rg+i8/s0NWyk/g3LXvPPJ9BYcQFfV3d3JpkImMB83c5tbrFtE7Io0Uov0MqEhKRrEd0/ /B00oahA9VK286ch70ZgQX9KWibCmtGVFgUCeE5ien9ew8Ayr+MOjSm0BSwOgvIMfCPD a4Fpj3kJ9T9hbc2xCKpy9lxg0dmVjMqFRY7fdATI6H+XP2xoy1APBNUg/iLxqOxOz87V 8nCA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=pln9LT1uNdfaqhJNGD+O26m6HebQTGwT47fBp9Sl9RM=; b=D5yWpZGexIv/ohkg+iTMghZ22KnW6QCUkvv2hLqDr4v8729Gij6Ok0modKteUJosWa 8IqhSVe0Cwc59UhbdmuwyCWoZlkTtKRcWWprozeN0evKMcgIDLIK8A7EsQcCfsSGU+3q nr8uOXvDYXntwOw7Uv9XjjDvHuwb7tosf5MrMqvNlU8KGWrYPCExRwFhJ9vQaaw9Lp1u E5SLVOgwYTzhEx3yL9y0uHJ7/1hz1+hCz/gE6+4uw3++EVsfagE+/FoPSV1XDe+oveI1 uG6A1LCivF8IVhD6m9j3a5HYQy80XB02Ic7Wt51EE/mBduBKt4UQK16kl7sE7hokHDcw +M3A== X-Gm-Message-State: APjAAAWRM0lImwIuqLXoMIYGpszhrt4uXLluxw11mAvvSUvqi9IfbGaR GkKHqTnQ94DAw/8LY95WCu8oRHtBQ4XviyJXXjilNA== X-Received: by 2002:aca:220f:: with SMTP id b15mr541042oic.73.1557243323110; Tue, 07 May 2019 08:35:23 -0700 (PDT) MIME-Version: 1.0 References: <20190426050039.17460-1-pagupta@redhat.com> <20190426050039.17460-3-pagupta@redhat.com> In-Reply-To: <20190426050039.17460-3-pagupta@redhat.com> From: Dan Williams Date: Tue, 7 May 2019 08:35:12 -0700 Message-ID: Subject: Re: [PATCH v7 2/6] virtio-pmem: Add virtio pmem driver To: Pankaj Gupta Cc: linux-nvdimm , Linux Kernel Mailing List , virtualization@lists.linux-foundation.org, KVM list , linux-fsdevel , Linux ACPI , Qemu Developers , linux-ext4 , linux-xfs , Ross Zwisler , Vishal L Verma , Dave Jiang , "Michael S. Tsirkin" , Jason Wang , Matthew Wilcox , "Rafael J. Wysocki" , Christoph Hellwig , Len Brown , Jan Kara , "Theodore Ts'o" , Andreas Dilger , "Darrick J. Wong" , lcapitulino@redhat.com, Kevin Wolf , Igor Mammedov , jmoyer , Nitesh Narayan Lal , Rik van Riel , Stefan Hajnoczi , Andrea Arcangeli , David Hildenbrand , david , cohuck@redhat.com, Xiao Guangrong , Paolo Bonzini , kilobyte@angband.pl, yuval shaia Content-Type: text/plain; charset="UTF-8" Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Hi Pankaj, Some minor file placement comments below. On Thu, Apr 25, 2019 at 10:02 PM Pankaj Gupta wrote: > > This patch adds virtio-pmem driver for KVM guest. > > Guest reads the persistent memory range information from > Qemu over VIRTIO and registers it on nvdimm_bus. It also > creates a nd_region object with the persistent memory > range information so that existing 'nvdimm/pmem' driver > can reserve this into system memory map. This way > 'virtio-pmem' driver uses existing functionality of pmem > driver to register persistent memory compatible for DAX > capable filesystems. > > This also provides function to perform guest flush over > VIRTIO from 'pmem' driver when userspace performs flush > on DAX memory range. > > Signed-off-by: Pankaj Gupta > --- > drivers/nvdimm/virtio_pmem.c | 114 +++++++++++++++++++++++++++++ > drivers/virtio/Kconfig | 10 +++ > drivers/virtio/Makefile | 1 + > drivers/virtio/pmem.c | 118 +++++++++++++++++++++++++++++++ > include/linux/virtio_pmem.h | 60 ++++++++++++++++ > include/uapi/linux/virtio_ids.h | 1 + > include/uapi/linux/virtio_pmem.h | 10 +++ > 7 files changed, 314 insertions(+) > create mode 100644 drivers/nvdimm/virtio_pmem.c > create mode 100644 drivers/virtio/pmem.c > create mode 100644 include/linux/virtio_pmem.h > create mode 100644 include/uapi/linux/virtio_pmem.h > > diff --git a/drivers/nvdimm/virtio_pmem.c b/drivers/nvdimm/virtio_pmem.c > new file mode 100644 > index 000000000000..66b582f751a3 > --- /dev/null > +++ b/drivers/nvdimm/virtio_pmem.c > @@ -0,0 +1,114 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * virtio_pmem.c: Virtio pmem Driver > + * > + * Discovers persistent memory range information > + * from host and provides a virtio based flushing > + * interface. > + */ > +#include > +#include "nd.h" > + > + /* The interrupt handler */ > +void host_ack(struct virtqueue *vq) > +{ > + unsigned int len; > + unsigned long flags; > + struct virtio_pmem_request *req, *req_buf; > + struct virtio_pmem *vpmem = vq->vdev->priv; > + > + spin_lock_irqsave(&vpmem->pmem_lock, flags); > + while ((req = virtqueue_get_buf(vq, &len)) != NULL) { > + req->done = true; > + wake_up(&req->host_acked); > + > + if (!list_empty(&vpmem->req_list)) { > + req_buf = list_first_entry(&vpmem->req_list, > + struct virtio_pmem_request, list); > + list_del(&vpmem->req_list); > + req_buf->wq_buf_avail = true; > + wake_up(&req_buf->wq_buf); > + } > + } > + spin_unlock_irqrestore(&vpmem->pmem_lock, flags); > +} > +EXPORT_SYMBOL_GPL(host_ack); > + > + /* The request submission function */ > +int virtio_pmem_flush(struct nd_region *nd_region) > +{ > + int err; > + unsigned long flags; > + struct scatterlist *sgs[2], sg, ret; > + struct virtio_device *vdev = nd_region->provider_data; > + struct virtio_pmem *vpmem = vdev->priv; > + struct virtio_pmem_request *req; > + > + might_sleep(); > + req = kmalloc(sizeof(*req), GFP_KERNEL); > + if (!req) > + return -ENOMEM; > + > + req->done = req->wq_buf_avail = false; > + strcpy(req->name, "FLUSH"); > + init_waitqueue_head(&req->host_acked); > + init_waitqueue_head(&req->wq_buf); > + sg_init_one(&sg, req->name, strlen(req->name)); > + sgs[0] = &sg; > + sg_init_one(&ret, &req->ret, sizeof(req->ret)); > + sgs[1] = &ret; > + > + spin_lock_irqsave(&vpmem->pmem_lock, flags); > + err = virtqueue_add_sgs(vpmem->req_vq, sgs, 1, 1, req, GFP_ATOMIC); > + if (err) { > + dev_err(&vdev->dev, "failed to send command to virtio pmem device\n"); > + > + list_add_tail(&vpmem->req_list, &req->list); > + spin_unlock_irqrestore(&vpmem->pmem_lock, flags); > + > + /* When host has read buffer, this completes via host_ack */ > + wait_event(req->wq_buf, req->wq_buf_avail); > + spin_lock_irqsave(&vpmem->pmem_lock, flags); > + } > + err = virtqueue_kick(vpmem->req_vq); > + spin_unlock_irqrestore(&vpmem->pmem_lock, flags); > + > + if (!err) { > + err = -EIO; > + goto ret; > + } > + /* When host has read buffer, this completes via host_ack */ > + wait_event(req->host_acked, req->done); > + err = req->ret; > +ret: > + kfree(req); > + return err; > +}; > + > + /* The asynchronous flush callback function */ > +int async_pmem_flush(struct nd_region *nd_region, struct bio *bio) > +{ > + int rc = 0; > + > + /* Create child bio for asynchronous flush and chain with > + * parent bio. Otherwise directly call nd_region flush. > + */ > + if (bio && bio->bi_iter.bi_sector != -1) { > + struct bio *child = bio_alloc(GFP_ATOMIC, 0); > + > + if (!child) > + return -ENOMEM; > + bio_copy_dev(child, bio); > + child->bi_opf = REQ_PREFLUSH; > + child->bi_iter.bi_sector = -1; > + bio_chain(child, bio); > + submit_bio(child); > + } else { > + if (virtio_pmem_flush(nd_region)) > + rc = -EIO; > + } > + > + return rc; > +}; > +EXPORT_SYMBOL_GPL(async_pmem_flush); > +MODULE_LICENSE("GPL"); > diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig > index 35897649c24f..9f634a2ed638 100644 > --- a/drivers/virtio/Kconfig > +++ b/drivers/virtio/Kconfig > @@ -42,6 +42,16 @@ config VIRTIO_PCI_LEGACY > > If unsure, say Y. > > +config VIRTIO_PMEM > + tristate "Support for virtio pmem driver" > + depends on VIRTIO > + depends on LIBNVDIMM > + help > + This driver provides support for virtio based flushing interface > + for persistent memory range. > + > + If unsure, say M. > + > config VIRTIO_BALLOON > tristate "Virtio balloon driver" > depends on VIRTIO > diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile > index 3a2b5c5dcf46..143ce91eabe9 100644 > --- a/drivers/virtio/Makefile > +++ b/drivers/virtio/Makefile > @@ -6,3 +6,4 @@ virtio_pci-y := virtio_pci_modern.o virtio_pci_common.o > virtio_pci-$(CONFIG_VIRTIO_PCI_LEGACY) += virtio_pci_legacy.o > obj-$(CONFIG_VIRTIO_BALLOON) += virtio_balloon.o > obj-$(CONFIG_VIRTIO_INPUT) += virtio_input.o > +obj-$(CONFIG_VIRTIO_PMEM) += pmem.o ../nvdimm/virtio_pmem.o > diff --git a/drivers/virtio/pmem.c b/drivers/virtio/pmem.c > new file mode 100644 > index 000000000000..309788628e41 > --- /dev/null > +++ b/drivers/virtio/pmem.c It's not clear to me why this driver is located in drivers/virtio/ > @@ -0,0 +1,118 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * virtio_pmem.c: Virtio pmem Driver > + * > + * Discovers persistent memory range information > + * from host and registers the virtual pmem device > + * with libnvdimm core. > + */ > +#include > +#include <../../drivers/nvdimm/nd.h> ...especially because it seems to require nvdimm internals. However I don't see why that header is included. In any event lets move this to drivers/nvdimm/virtio.c to live alongside the other generic bus provider drivers/nvdimm/e820.c. > + > +static struct virtio_device_id id_table[] = { > + { VIRTIO_ID_PMEM, VIRTIO_DEV_ANY_ID }, > + { 0 }, > +}; > + > + /* Initialize virt queue */ > +static int init_vq(struct virtio_pmem *vpmem) > +{ > + /* single vq */ > + vpmem->req_vq = virtio_find_single_vq(vpmem->vdev, > + host_ack, "flush_queue"); > + if (IS_ERR(vpmem->req_vq)) > + return PTR_ERR(vpmem->req_vq); > + > + spin_lock_init(&vpmem->pmem_lock); > + INIT_LIST_HEAD(&vpmem->req_list); > + > + return 0; > +}; > + > +static int virtio_pmem_probe(struct virtio_device *vdev) > +{ > + int err = 0; > + struct resource res; > + struct virtio_pmem *vpmem; > + struct nd_region_desc ndr_desc = {}; > + int nid = dev_to_node(&vdev->dev); > + struct nd_region *nd_region; > + > + if (!vdev->config->get) { > + dev_err(&vdev->dev, "%s failure: config access disabled\n", > + __func__); > + return -EINVAL; > + } > + > + vpmem = devm_kzalloc(&vdev->dev, sizeof(*vpmem), GFP_KERNEL); > + if (!vpmem) { > + err = -ENOMEM; > + goto out_err; > + } > + > + vpmem->vdev = vdev; > + vdev->priv = vpmem; > + err = init_vq(vpmem); > + if (err) > + goto out_err; > + > + virtio_cread(vpmem->vdev, struct virtio_pmem_config, > + start, &vpmem->start); > + virtio_cread(vpmem->vdev, struct virtio_pmem_config, > + size, &vpmem->size); > + > + res.start = vpmem->start; > + res.end = vpmem->start + vpmem->size-1; > + vpmem->nd_desc.provider_name = "virtio-pmem"; > + vpmem->nd_desc.module = THIS_MODULE; > + > + vpmem->nvdimm_bus = nvdimm_bus_register(&vdev->dev, > + &vpmem->nd_desc); > + if (!vpmem->nvdimm_bus) > + goto out_vq; > + > + dev_set_drvdata(&vdev->dev, vpmem->nvdimm_bus); > + > + ndr_desc.res = &res; > + ndr_desc.numa_node = nid; > + ndr_desc.flush = async_pmem_flush; > + set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags); > + set_bit(ND_REGION_ASYNC, &ndr_desc.flags); > + nd_region = nvdimm_pmem_region_create(vpmem->nvdimm_bus, &ndr_desc); > + > + if (!nd_region) > + goto out_nd; > + nd_region->provider_data = dev_to_virtio > + (nd_region->dev.parent->parent); > + return 0; > +out_nd: > + err = -ENXIO; > + nvdimm_bus_unregister(vpmem->nvdimm_bus); > +out_vq: > + vdev->config->del_vqs(vdev); > +out_err: > + dev_err(&vdev->dev, "failed to register virtio pmem memory\n"); > + return err; > +} > + > +static void virtio_pmem_remove(struct virtio_device *vdev) > +{ > + struct nvdimm_bus *nvdimm_bus = dev_get_drvdata(&vdev->dev); > + > + nvdimm_bus_unregister(nvdimm_bus); > + vdev->config->del_vqs(vdev); > + vdev->config->reset(vdev); > +} > + > +static struct virtio_driver virtio_pmem_driver = { > + .driver.name = KBUILD_MODNAME, > + .driver.owner = THIS_MODULE, > + .id_table = id_table, > + .probe = virtio_pmem_probe, > + .remove = virtio_pmem_remove, > +}; > + > +module_virtio_driver(virtio_pmem_driver); > +MODULE_DEVICE_TABLE(virtio, id_table); > +MODULE_DESCRIPTION("Virtio pmem driver"); > +MODULE_LICENSE("GPL"); > diff --git a/include/linux/virtio_pmem.h b/include/linux/virtio_pmem.h > new file mode 100644 > index 000000000000..ab1da877575d > --- /dev/null > +++ b/include/linux/virtio_pmem.h Why is this a global header? Seems it can move to drivers/nvdimm/virtio.h. Also, I'd like to get a virtio ack from Michael (mst@redhat.com) before taking this through the nvdimm tree. > @@ -0,0 +1,60 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * virtio_pmem.h: virtio pmem Driver > + * > + * Discovers persistent memory range information > + * from host and provides a virtio based flushing > + * interface. > + **/ > + > +#ifndef _LINUX_VIRTIO_PMEM_H > +#define _LINUX_VIRTIO_PMEM_H > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +struct virtio_pmem_request { > + /* Host return status corresponding to flush request */ > + int ret; > + > + /* command name*/ > + char name[16]; > + > + /* Wait queue to process deferred work after ack from host */ > + wait_queue_head_t host_acked; > + bool done; > + > + /* Wait queue to process deferred work after virt queue buffer avail */ > + wait_queue_head_t wq_buf; > + bool wq_buf_avail; > + struct list_head list; > +}; > + > +struct virtio_pmem { > + struct virtio_device *vdev; > + > + /* Virtio pmem request queue */ > + struct virtqueue *req_vq; > + > + /* nvdimm bus registers virtio pmem device */ > + struct nvdimm_bus *nvdimm_bus; > + struct nvdimm_bus_descriptor nd_desc; > + > + /* List to store deferred work if virtqueue is full */ > + struct list_head req_list; > + > + /* Synchronize virtqueue data */ > + spinlock_t pmem_lock; > + > + /* Memory region information */ > + uint64_t start; > + uint64_t size; > +}; > + > +void host_ack(struct virtqueue *vq); > +int async_pmem_flush(struct nd_region *nd_region, struct bio *bio); > +#endif > diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h > index 6d5c3b2d4f4d..32b2f94d1f58 100644 > --- a/include/uapi/linux/virtio_ids.h > +++ b/include/uapi/linux/virtio_ids.h > @@ -43,5 +43,6 @@ > #define VIRTIO_ID_INPUT 18 /* virtio input */ > #define VIRTIO_ID_VSOCK 19 /* virtio vsock transport */ > #define VIRTIO_ID_CRYPTO 20 /* virtio crypto */ > +#define VIRTIO_ID_PMEM 27 /* virtio pmem */ > > #endif /* _LINUX_VIRTIO_IDS_H */ > diff --git a/include/uapi/linux/virtio_pmem.h b/include/uapi/linux/virtio_pmem.h > new file mode 100644 > index 000000000000..fa3f7d52717a > --- /dev/null > +++ b/include/uapi/linux/virtio_pmem.h > @@ -0,0 +1,10 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > + > +#ifndef _UAPI_LINUX_VIRTIO_PMEM_H > +#define _UAPI_LINUX_VIRTIO_PMEM_H > + > +struct virtio_pmem_config { > + __le64 start; > + __le64 size; > +}; > +#endif > -- > 2.20.1 >