Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754377AbbBTKO5 (ORCPT ); Fri, 20 Feb 2015 05:14:57 -0500 Received: from e06smtp13.uk.ibm.com ([195.75.94.109]:35620 "EHLO e06smtp13.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754331AbbBTKOy (ORCPT ); Fri, 20 Feb 2015 05:14:54 -0500 Subject: [PATCH 2/3] vhost: add support for legacy virtio From: Greg Kurz To: "Michael S. Tsirkin" Cc: Cedric Le Goater , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Date: Fri, 20 Feb 2015 11:14:47 +0100 Message-ID: <20150220100746.18608.15083.stgit@bahia.local> In-Reply-To: <20150220100724.18608.74654.stgit@bahia.local> References: <20150220100724.18608.74654.stgit@bahia.local> User-Agent: StGit/0.17-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15022010-0013-0000-0000-000003088949 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2539 Lines: 73 Signed-off-by: Greg Kurz --- drivers/vhost/vhost.h | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) Michael, The vhost_is_little_endian() helper adds unconditionnal overhead to fixed endian architectures: that is all architectures except arm and ppc64. This was addressed in QEMU with a TARGET_IS_BIENDIAN macro. Please give an advice about how to address this in the vhost code. Thanks. diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index ce2c68e..21e7d6a 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -176,34 +176,42 @@ static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit) return vq->acked_features & (1ULL << bit); } +static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq) +{ + if (vhost_has_feature(vq, VIRTIO_F_VERSION_1)) + return true; + else + return !vq->legacy_big_endian; +} + /* Memory accessors */ static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val) { - return __virtio16_to_cpu(vhost_has_feature(vq, VIRTIO_F_VERSION_1), val); + return __virtio16_to_cpu(vhost_is_little_endian(vq), val); } static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val) { - return __cpu_to_virtio16(vhost_has_feature(vq, VIRTIO_F_VERSION_1), val); + return __cpu_to_virtio16(vhost_is_little_endian(vq), val); } static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val) { - return __virtio32_to_cpu(vhost_has_feature(vq, VIRTIO_F_VERSION_1), val); + return __virtio32_to_cpu(vhost_is_little_endian(vq), val); } static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val) { - return __cpu_to_virtio32(vhost_has_feature(vq, VIRTIO_F_VERSION_1), val); + return __cpu_to_virtio32(vhost_is_little_endian(vq), val); } static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val) { - return __virtio64_to_cpu(vhost_has_feature(vq, VIRTIO_F_VERSION_1), val); + return __virtio64_to_cpu(vhost_is_little_endian(vq), val); } static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val) { - return __cpu_to_virtio64(vhost_has_feature(vq, VIRTIO_F_VERSION_1), val); + return __cpu_to_virtio64(vhost_is_little_endian(vq), val); } #endif -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/