Re: [Qemu-devel] [PATCH v3 3/3] virtio: add vhost-user-fs-pci device

[piaojun <piaojun@huawei.com>]

On 2019/9/18 0:00, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> 
> Add the PCI version of vhost-user-fs.
> 
> Launch QEMU like this:
> 
>   qemu -chardev socket,path=/tmp/vhost-fs.sock,id=chr0
>        -device x-vhost-user-fs-pci,tag=myfs,chardev=chr0
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
> ---
>  hw/virtio/Makefile.objs       |  1 +
>  hw/virtio/vhost-user-fs-pci.c | 85 +++++++++++++++++++++++++++++++++++
>  2 files changed, 86 insertions(+)
>  create mode 100644 hw/virtio/vhost-user-fs-pci.c
> 
> diff --git a/hw/virtio/Makefile.objs b/hw/virtio/Makefile.objs
> index 47ffbf22c4..e2f70fbb89 100644
> --- a/hw/virtio/Makefile.objs
> +++ b/hw/virtio/Makefile.objs
> @@ -15,6 +15,7 @@ obj-$(CONFIG_VHOST_USER_FS) += vhost-user-fs.o
>  obj-$(call land,$(CONFIG_VIRTIO_CRYPTO),$(CONFIG_VIRTIO_PCI)) += virtio-crypto-pci.o
>  obj-$(CONFIG_VIRTIO_PMEM) += virtio-pmem.o
>  common-obj-$(call land,$(CONFIG_VIRTIO_PMEM),$(CONFIG_VIRTIO_PCI)) += virtio-pmem-pci.o
> +obj-$(call land,$(CONFIG_VHOST_USER_FS),$(CONFIG_VIRTIO_PCI)) += vhost-user-fs-pci.o
>  obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock.o
>  
>  ifeq ($(CONFIG_VIRTIO_PCI),y)
> diff --git a/hw/virtio/vhost-user-fs-pci.c b/hw/virtio/vhost-user-fs-pci.c
> new file mode 100644
> index 0000000000..0e70985094
> --- /dev/null
> +++ b/hw/virtio/vhost-user-fs-pci.c
> @@ -0,0 +1,85 @@
> +/*
> + * Vhost-user filesystem virtio device PCI glue
> + *
> + * Copyright 2018-2019 Red Hat, Inc.
> + *
> + * Authors:
> + *  Dr. David Alan Gilbert <dgilbert@redhat.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or
> + * (at your option) any later version.  See the COPYING file in the
> + * top-level directory.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "hw/qdev-properties.h"
> +#include "hw/virtio/vhost-user-fs.h"
> +#include "virtio-pci.h"
> +
> +struct VHostUserFSPCI {
> +    VirtIOPCIProxy parent_obj;
> +    VHostUserFS vdev;
> +};
> +
> +typedef struct VHostUserFSPCI VHostUserFSPCI;
> +
> +#define TYPE_VHOST_USER_FS_PCI "vhost-user-fs-pci-base"
> +
> +#define VHOST_USER_FS_PCI(obj) \
> +        OBJECT_CHECK(VHostUserFSPCI, (obj), TYPE_VHOST_USER_FS_PCI)
> +
> +static Property vhost_user_fs_pci_properties[] = {
> +    DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors,
> +                       DEV_NVECTORS_UNSPECIFIED),
> +    DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static void vhost_user_fs_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
> +{
> +    VHostUserFSPCI *dev = VHOST_USER_FS_PCI(vpci_dev);
> +    DeviceState *vdev = DEVICE(&dev->vdev);
> +
> +    if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
> +        vpci_dev->nvectors = dev->vdev.conf.num_request_queues + 1;
> +    }
> +
> +    qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
> +    object_property_set_bool(OBJECT(vdev), true, "realized", errp);
> +}
> +
> +static void vhost_user_fs_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 = vhost_user_fs_pci_realize;
> +    set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
> +    dc->props = vhost_user_fs_pci_properties;
> +    pcidev_k->vendor_id = PCI_VENDOR_ID_REDHAT_QUMRANET;
> +    pcidev_k->device_id = 0; /* Set by virtio-pci based on virtio id */

Why not set *PCI_DEVICE_ID_VIRTIO_FS* here just like virtio_blk? I'm
not very familiar with this code, and just compare it with the other
same logic.

Thanks,
Jun