From: Nicholas Bellinger <[email protected]> This patch adds a VHOST_SCSI_FEATURES mask minus VIRTIO_RING_F_EVENT_IDX so that vhost-scsi-pci userspace will strip this feature bit once GET_FEATURES reports it as being unsupported on the host.
This is to avoid a bug where ->handle_kicks() are missed when EVENT_IDX is enabled by default in userspace code. (mst: Rename to VHOST_SCSI_FEATURES add comment) Cc: Michael S. Tsirkin <[email protected]> Cc: Asias He <[email protected]> Cc: Paolo Bonzini <[email protected]> Signed-off-by: Nicholas Bellinger <[email protected]> --- drivers/vhost/tcm_vhost.c | 13 +++++++++++-- 1 files changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c index 0524267..4a68c1f 100644 --- a/drivers/vhost/tcm_vhost.c +++ b/drivers/vhost/tcm_vhost.c @@ -60,6 +60,15 @@ enum { VHOST_SCSI_VQ_IO = 2, }; +/* + * VIRTIO_RING_F_EVENT_IDX seems broken. Not sure the bug is in + * kernel but disabling it helps. + * TODO: debug and remove the workaround. + */ +enum { + VHOST_SCSI_FEATURES = VHOST_FEATURES & (~VIRTIO_RING_F_EVENT_IDX) +}; + #define VHOST_SCSI_MAX_TARGET 256 #define VHOST_SCSI_MAX_VQ 128 @@ -981,7 +990,7 @@ static void vhost_scsi_flush(struct vhost_scsi *vs) static int vhost_scsi_set_features(struct vhost_scsi *vs, u64 features) { - if (features & ~VHOST_FEATURES) + if (features & ~VHOST_SCSI_FEATURES) return -EOPNOTSUPP; mutex_lock(&vs->dev.mutex); @@ -1027,7 +1036,7 @@ static long vhost_scsi_ioctl(struct file *f, unsigned int ioctl, return -EFAULT; return 0; case VHOST_GET_FEATURES: - features = VHOST_FEATURES; + features = VHOST_SCSI_FEATURES; if (copy_to_user(featurep, &features, sizeof features)) return -EFAULT; return 0; -- 1.7.2.5 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
