On Mon, Oct 04, 2021 at 03:33:47PM +0100, Stefan Hajnoczi wrote:
> On Thu, Sep 30, 2021 at 11:30:33AM -0400, Vivek Goyal wrote:
> > Daemon specifies size of notification buffer needed and that should be
> > done using config space.
> >
> > Only ->notify_buf_size value of config space comes from daemon. Rest of
> > it is filled by qemu device emulation code.
> >
> > Signed-off-by: Vivek Goyal <vgo...@redhat.com>
> > Signed-off-by: Ioannis Angelakopoulos <iange...@redhat.com>
> > ---
> > hw/virtio/vhost-user-fs.c | 27 +++++++++++++++++++
> > include/hw/virtio/vhost-user-fs.h | 2 ++
> > include/standard-headers/linux/virtio_fs.h | 2 ++
> > tools/virtiofsd/fuse_virtio.c | 31 ++++++++++++++++++++++
> > 4 files changed, 62 insertions(+)
> >
> > diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c
> > index 6bafcf0243..68a94708b4 100644
> > --- a/hw/virtio/vhost-user-fs.c
> > +++ b/hw/virtio/vhost-user-fs.c
> > @@ -36,15 +36,41 @@ static const int user_feature_bits[] = {
> > VHOST_INVALID_FEATURE_BIT
> > };
> >
> > +static int vhost_user_fs_handle_config_change(struct vhost_dev *dev)
> > +{
> > + return 0;
> > +}
> > +
> > +const VhostDevConfigOps fs_ops = {
> > + .vhost_dev_config_notifier = vhost_user_fs_handle_config_change,
> > +};
> > +
> > static void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
> > {
> > VHostUserFS *fs = VHOST_USER_FS(vdev);
> > struct virtio_fs_config fscfg = {};
> > + Error *local_err = NULL;
> > + int ret;
> > +
> > + /*
> > + * As of now we only get notification buffer size from device. And
> > that's
> > + * needed only if notification queue is enabled.
> > + */
> > + if (fs->notify_enabled) {
> > + ret = vhost_dev_get_config(&fs->vhost_dev, (uint8_t *)&fs->fscfg,
> > + sizeof(struct virtio_fs_config),
> > + &local_err);
> > + if (ret) {
> > + error_report_err(local_err);
> > + return;
> > + }
> > + }
> >
> > memcpy((char *)fscfg.tag, fs->conf.tag,
> > MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));
> >
> > virtio_stl_p(vdev, &fscfg.num_request_queues,
> > fs->conf.num_request_queues);
> > + virtio_stl_p(vdev, &fscfg.notify_buf_size, fs->fscfg.notify_buf_size);
> >
> > memcpy(config, &fscfg, sizeof(fscfg));
> > }
> > @@ -316,6 +342,7 @@ static void vuf_device_realize(DeviceState *dev, Error
> > **errp)
> > sizeof(struct virtio_fs_config));
> >
> > vuf_create_vqs(vdev, true);
> > + vhost_dev_set_config_notifier(&fs->vhost_dev, &fs_ops);
> > ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
> > VHOST_BACKEND_TYPE_USER, 0, errp);
> > if (ret < 0) {
> > diff --git a/include/hw/virtio/vhost-user-fs.h
> > b/include/hw/virtio/vhost-user-fs.h
> > index 95dc0dd402..3b114ee260 100644
> > --- a/include/hw/virtio/vhost-user-fs.h
> > +++ b/include/hw/virtio/vhost-user-fs.h
> > @@ -14,6 +14,7 @@
> > #ifndef _QEMU_VHOST_USER_FS_H
> > #define _QEMU_VHOST_USER_FS_H
> >
> > +#include "standard-headers/linux/virtio_fs.h"
> > #include "hw/virtio/virtio.h"
> > #include "hw/virtio/vhost.h"
> > #include "hw/virtio/vhost-user.h"
> > @@ -37,6 +38,7 @@ struct VHostUserFS {
> > struct vhost_virtqueue *vhost_vqs;
> > struct vhost_dev vhost_dev;
> > VhostUserState vhost_user;
> > + struct virtio_fs_config fscfg;
> > VirtQueue **req_vqs;
> > VirtQueue *hiprio_vq;
> > VirtQueue *notification_vq;
> > diff --git a/include/standard-headers/linux/virtio_fs.h
> > b/include/standard-headers/linux/virtio_fs.h
> > index b7f015186e..867d18acf6 100644
> > --- a/include/standard-headers/linux/virtio_fs.h
> > +++ b/include/standard-headers/linux/virtio_fs.h
> > @@ -17,6 +17,8 @@ struct virtio_fs_config {
> >
> > /* Number of request queues */
> > uint32_t num_request_queues;
> > + /* Size of notification buffer */
> > + uint32_t notify_buf_size;
> > } QEMU_PACKED;
> >
> > /* For the id field in virtio_pci_shm_cap */
>
> Please put all the include/standard-headers/linux/ changes into a single
> commit that imports these changes from linux.git. Changes to this header
> shouldn't be hand-written, use scripts/update-linux-headers.sh instead.
Will do. These changes are not in kernel yet. So will use
update-linux-headers.sh when changes are upstreamed. But agreed,
that this change should be in separate patch even for review
purpose (before it is merged in kernel).
>
> > diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
> > index f5b87a508a..3b720c5d4a 100644
> > --- a/tools/virtiofsd/fuse_virtio.c
> > +++ b/tools/virtiofsd/fuse_virtio.c
> > @@ -856,6 +856,35 @@ static bool fv_queue_order(VuDev *dev, int qidx)
> > return false;
> > }
> >
> > +static uint64_t fv_get_protocol_features(VuDev *dev)
> > +{
> > + return 1ull << VHOST_USER_PROTOCOL_F_CONFIG;
> > +}
> > +
> > +static int fv_get_config(VuDev *dev, uint8_t *config, uint32_t len)
> > +{
> > + struct virtio_fs_config fscfg = {};
> > + unsigned notify_size, roundto = 64;
> > + union fuse_notify_union {
> > + struct fuse_notify_poll_wakeup_out wakeup_out;
> > + struct fuse_notify_inval_inode_out inode_out;
> > + struct fuse_notify_inval_entry_out entry_out;
> > + struct fuse_notify_delete_out delete_out;
> > + struct fuse_notify_store_out store_out;
> > + struct fuse_notify_retrieve_out retrieve_out;
> > + };
> > +
> > + notify_size = sizeof(struct fuse_out_header) +
> > + sizeof(union fuse_notify_union);
> > + notify_size = ((notify_size + roundto) / roundto) * roundto;
>
> Why is the size rounded to 64 bytes?
Hmm.., I really can't remember why did I do that. Maybe I thought it
is just nice to round it to 64 bytes. I can get rid of this rounding
if it s not making sense.
Vivek
