diff options
| author | Nicholas Bellinger <nab@linux-iscsi.org> | 2013-03-27 17:23:41 -0700 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2013-03-28 23:42:47 -0700 |
| commit | 5dade71050e799d8679698a6145e2ba46cdeac2a (patch) | |
| tree | 305a6afdd30ea073b0ce6fc8ee952405993bff16 /drivers/vhost/tcm_vhost.c | |
| parent | 8f27d487bcc2bd603c2d87e1729abcbc301f15db (diff) | |
tcm_vhost: Avoid VIRTIO_RING_F_EVENT_IDX feature bit
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)
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Asias He <asias@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/vhost/tcm_vhost.c')
| -rw-r--r-- | 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 43fb11ee2e8..2968b493465 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 @@ -946,7 +955,7 @@ 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); @@ -992,7 +1001,7 @@ 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; |