From patchwork Fri Mar 29 00:50:26 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Nicholas A. Bellinger" X-Patchwork-Id: 2360001 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 0DC6BDF2A1 for ; Fri, 29 Mar 2013 01:01:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754124Ab3C2BBd (ORCPT ); Thu, 28 Mar 2013 21:01:33 -0400 Received: from mail.linux-iscsi.org ([67.23.28.174]:39733 "EHLO linux-iscsi.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753283Ab3C2BBd (ORCPT ); Thu, 28 Mar 2013 21:01:33 -0400 Received: from linux-iscsi.org (localhost [127.0.0.1]) by linux-iscsi.org (Postfix) with ESMTP id 8173222D9D1; Fri, 29 Mar 2013 00:50:28 +0000 (UTC) From: "Nicholas A. Bellinger" To: target-devel Cc: lf-virt , kvm-devel , "Michael S. Tsirkin" , Stefan Hajnoczi , Paolo Bonzini , Asias He , Nicholas Bellinger Subject: [PATCH-v2] tcm_vhost: Avoid VIRTIO_RING_F_EVENT_IDX feature bit Date: Fri, 29 Mar 2013 00:50:26 +0000 Message-Id: <1364518226-31372-1-git-send-email-nab@linux-iscsi.org> X-Mailer: git-send-email 1.7.2.5 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Nicholas Bellinger 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 Cc: Asias He Cc: Paolo Bonzini Signed-off-by: Nicholas Bellinger Reviewed-by: Asias He --- 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;