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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 CE2D5ECDE5F for ; Thu, 19 Jul 2018 12:48:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 834372084C for ; Thu, 19 Jul 2018 12:48:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 834372084C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731641AbeGSNb1 (ORCPT ); Thu, 19 Jul 2018 09:31:27 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:41704 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731542AbeGSNb1 (ORCPT ); Thu, 19 Jul 2018 09:31:27 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DF36F7A7E5; Thu, 19 Jul 2018 12:48:25 +0000 (UTC) Received: from doriath (ovpn-116-197.phx2.redhat.com [10.3.116.197]) by smtp.corp.redhat.com (Postfix) with ESMTP id ECAB22026D7E; Thu, 19 Jul 2018 12:48:20 +0000 (UTC) Date: Thu, 19 Jul 2018 08:48:19 -0400 From: Luiz Capitulino To: Stefan Hajnoczi Cc: Pankaj Gupta , kwolf@redhat.com, haozhong zhang , jack@suse.cz, xiaoguangrong eric , kvm@vger.kernel.org, riel@surriel.com, linux-nvdimm@ml01.01.org, david@redhat.com, ross zwisler , linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, hch@infradead.org, imammedo@redhat.com, mst@redhat.com, niteshnarayanlal@hotmail.com, pbonzini@redhat.com, dan j williams , nilal@redhat.com Subject: Re: [Qemu-devel] [RFC v3] qemu: Add virtio pmem device Message-ID: <20180719084819.730b7971@doriath> In-Reply-To: <20180719121635.GA28107@stefanha-x1.localdomain> References: <20180713075232.9575-1-pagupta@redhat.com> <20180713075232.9575-4-pagupta@redhat.com> <20180718085529.133a0a22@doriath> <367397176.52317488.1531979293251.JavaMail.zimbra@redhat.com> <20180719121635.GA28107@stefanha-x1.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Thu, 19 Jul 2018 12:48:25 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Thu, 19 Jul 2018 12:48:25 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'lcapitulino@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 19 Jul 2018 13:16:35 +0100 Stefan Hajnoczi wrote: > On Thu, Jul 19, 2018 at 01:48:13AM -0400, Pankaj Gupta wrote: > > > > > > > > > This patch adds virtio-pmem Qemu device. > > > > > > > > This device presents memory address range information to guest > > > > which is backed by file backend type. It acts like persistent > > > > memory device for KVM guest. Guest can perform read and persistent > > > > write operations on this memory range with the help of DAX capable > > > > filesystem. > > > > > > > > Persistent guest writes are assured with the help of virtio based > > > > flushing interface. When guest userspace space performs fsync on > > > > file fd on pmem device, a flush command is send to Qemu over VIRTIO > > > > and host side flush/sync is done on backing image file. > > > > > > > > Changes from RFC v2: > > > > - Use aio_worker() to avoid Qemu from hanging with blocking fsync > > > > call - Stefan > > > > - Use virtio_st*_p() for endianess - Stefan > > > > - Correct indentation in qapi/misc.json - Eric > > > > > > > > Signed-off-by: Pankaj Gupta > > > > --- > > > > hw/virtio/Makefile.objs | 3 + > > > > hw/virtio/virtio-pci.c | 44 +++++ > > > > hw/virtio/virtio-pci.h | 14 ++ > > > > hw/virtio/virtio-pmem.c | 241 > > > > ++++++++++++++++++++++++++++ > > > > include/hw/pci/pci.h | 1 + > > > > include/hw/virtio/virtio-pmem.h | 42 +++++ > > > > include/standard-headers/linux/virtio_ids.h | 1 + > > > > qapi/misc.json | 26 ++- > > > > 8 files changed, 371 insertions(+), 1 deletion(-) > > > > create mode 100644 hw/virtio/virtio-pmem.c > > > > create mode 100644 include/hw/virtio/virtio-pmem.h > > > > > > > > diff --git a/hw/virtio/Makefile.objs b/hw/virtio/Makefile.objs > > > > index 1b2799cfd8..7f914d45d0 100644 > > > > --- a/hw/virtio/Makefile.objs > > > > +++ b/hw/virtio/Makefile.objs > > > > @@ -10,6 +10,9 @@ obj-$(CONFIG_VIRTIO_CRYPTO) += virtio-crypto.o > > > > obj-$(call land,$(CONFIG_VIRTIO_CRYPTO),$(CONFIG_VIRTIO_PCI)) += > > > > virtio-crypto-pci.o > > > > > > > > obj-$(CONFIG_LINUX) += vhost.o vhost-backend.o vhost-user.o > > > > +ifeq ($(CONFIG_MEM_HOTPLUG),y) > > > > +obj-$(CONFIG_LINUX) += virtio-pmem.o > > > > +endif > > > > obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock.o > > > > endif > > > > > > > > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c > > > > index 3a01fe90f0..93d3fc05c7 100644 > > > > --- a/hw/virtio/virtio-pci.c > > > > +++ b/hw/virtio/virtio-pci.c > > > > @@ -2521,6 +2521,49 @@ static const TypeInfo virtio_rng_pci_info = { > > > > .class_init = virtio_rng_pci_class_init, > > > > }; > > > > > > > > +/* virtio-pmem-pci */ > > > > + > > > > +static void virtio_pmem_pci_realize(VirtIOPCIProxy *vpci_dev, Error > > > > **errp) > > > > +{ > > > > + VirtIOPMEMPCI *vpmem = VIRTIO_PMEM_PCI(vpci_dev); > > > > + DeviceState *vdev = DEVICE(&vpmem->vdev); > > > > + > > > > + qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus)); > > > > + object_property_set_bool(OBJECT(vdev), true, "realized", errp); > > > > +} > > > > + > > > > +static void virtio_pmem_pci_class_init(ObjectClass *klass, void *data) > > > > +{ > > > > + DeviceClass *dc = DEVICE_CLASS(klass); > > > > + VirtioPCIClass *k = VIRTIO_PCI_CLASS(klass); > > > > + PCIDeviceClass *pcidev_k = PCI_DEVICE_CLASS(klass); > > > > + k->realize = virtio_pmem_pci_realize; > > > > + set_bit(DEVICE_CATEGORY_MISC, dc->categories); > > > > + pcidev_k->vendor_id = PCI_VENDOR_ID_REDHAT_QUMRANET; > > > > + pcidev_k->device_id = PCI_DEVICE_ID_VIRTIO_PMEM; > > > > + pcidev_k->revision = VIRTIO_PCI_ABI_VERSION; > > > > + pcidev_k->class_id = PCI_CLASS_OTHERS; > > > > +} > > > > + > > > > +static void virtio_pmem_pci_instance_init(Object *obj) > > > > +{ > > > > + VirtIOPMEMPCI *dev = VIRTIO_PMEM_PCI(obj); > > > > + > > > > + virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev), > > > > + TYPE_VIRTIO_PMEM); > > > > + object_property_add_alias(obj, "memdev", OBJECT(&dev->vdev), "memdev", > > > > + &error_abort); > > > > +} > > > > + > > > > +static const TypeInfo virtio_pmem_pci_info = { > > > > + .name = TYPE_VIRTIO_PMEM_PCI, > > > > + .parent = TYPE_VIRTIO_PCI, > > > > + .instance_size = sizeof(VirtIOPMEMPCI), > > > > + .instance_init = virtio_pmem_pci_instance_init, > > > > + .class_init = virtio_pmem_pci_class_init, > > > > +}; > > > > + > > > > + > > > > /* virtio-input-pci */ > > > > > > > > static Property virtio_input_pci_properties[] = { > > > > @@ -2714,6 +2757,7 @@ static void virtio_pci_register_types(void) > > > > type_register_static(&virtio_balloon_pci_info); > > > > type_register_static(&virtio_serial_pci_info); > > > > type_register_static(&virtio_net_pci_info); > > > > + type_register_static(&virtio_pmem_pci_info); > > > > #ifdef CONFIG_VHOST_SCSI > > > > type_register_static(&vhost_scsi_pci_info); > > > > #endif > > > > diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h > > > > index 813082b0d7..fe74fcad3f 100644 > > > > --- a/hw/virtio/virtio-pci.h > > > > +++ b/hw/virtio/virtio-pci.h > > > > @@ -19,6 +19,7 @@ > > > > #include "hw/virtio/virtio-blk.h" > > > > #include "hw/virtio/virtio-net.h" > > > > #include "hw/virtio/virtio-rng.h" > > > > +#include "hw/virtio/virtio-pmem.h" > > > > #include "hw/virtio/virtio-serial.h" > > > > #include "hw/virtio/virtio-scsi.h" > > > > #include "hw/virtio/virtio-balloon.h" > > > > @@ -57,6 +58,7 @@ typedef struct VirtIOInputHostPCI VirtIOInputHostPCI; > > > > typedef struct VirtIOGPUPCI VirtIOGPUPCI; > > > > typedef struct VHostVSockPCI VHostVSockPCI; > > > > typedef struct VirtIOCryptoPCI VirtIOCryptoPCI; > > > > +typedef struct VirtIOPMEMPCI VirtIOPMEMPCI; > > > > > > > > /* virtio-pci-bus */ > > > > > > > > @@ -274,6 +276,18 @@ struct VirtIOBlkPCI { > > > > VirtIOBlock vdev; > > > > }; > > > > > > > > +/* > > > > + * virtio-pmem-pci: This extends VirtioPCIProxy. > > > > + */ > > > > +#define TYPE_VIRTIO_PMEM_PCI "virtio-pmem-pci" > > > > +#define VIRTIO_PMEM_PCI(obj) \ > > > > + OBJECT_CHECK(VirtIOPMEMPCI, (obj), TYPE_VIRTIO_PMEM_PCI) > > > > + > > > > +struct VirtIOPMEMPCI { > > > > + VirtIOPCIProxy parent_obj; > > > > + VirtIOPMEM vdev; > > > > +}; > > > > + > > > > /* > > > > * virtio-balloon-pci: This extends VirtioPCIProxy. > > > > */ > > > > diff --git a/hw/virtio/virtio-pmem.c b/hw/virtio/virtio-pmem.c > > > > new file mode 100644 > > > > index 0000000000..08c96d7e80 > > > > --- /dev/null > > > > +++ b/hw/virtio/virtio-pmem.c > > > > @@ -0,0 +1,241 @@ > > > > +/* > > > > + * Virtio pmem device > > > > + * > > > > + * Copyright (C) 2018 Red Hat, Inc. > > > > + * Copyright (C) 2018 Pankaj Gupta > > > > + * > > > > + * This work is licensed under the terms of the GNU GPL, version 2. > > > > + * See the COPYING file in the top-level directory. > > > > + * > > > > + */ > > > > + > > > > +#include "qemu/osdep.h" > > > > +#include "qapi/error.h" > > > > +#include "qemu-common.h" > > > > +#include "qemu/error-report.h" > > > > +#include "hw/virtio/virtio-access.h" > > > > +#include "hw/virtio/virtio-pmem.h" > > > > +#include "hw/mem/memory-device.h" > > > > +#include "block/aio.h" > > > > +#include "block/thread-pool.h" > > > > + > > > > +typedef struct VirtIOPMEMresp { > > > > + int ret; > > > > +} VirtIOPMEMResp; > > > > + > > > > +typedef struct VirtIODeviceRequest { > > > > + VirtQueueElement elem; > > > > + int fd; > > > > + VirtIOPMEM *pmem; > > > > + VirtIOPMEMResp resp; > > > > +} VirtIODeviceRequest; > > > > + > > > > +static int worker_cb(void *opaque) > > > > +{ > > > > + VirtIODeviceRequest *req = opaque; > > > > + int err = 0; > > > > + > > > > + /* flush raw backing image */ > > > > + err = fsync(req->fd); > > > > + if (err != 0) { > > > > + err = errno; > > > > + } > > > > + req->resp.ret = err; > > > > > > Host question: are you returning the guest errno code to the host? > > > > No. I am returning error code from the host in-case of host fsync > > failure, otherwise returning zero. > > I think that's what Luiz meant. errno constants are not portable > between operating systems and architectures. Therefore they cannot be > used in external interfaces in software that expects to communicate with > other systems. Oh, thanks. Only saw this email now. > It will be necessary to define specific constants for virtio-pmem > instead of passing errno from the host to guest. Yes, defining your own constants work. But I think the only fsync() error that will make sense for the guest is EIO. The other errors only make sense for the host.