From patchwork Wed Jul 20 17:04:25 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andre Przywara X-Patchwork-Id: 9240023 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1D60960574 for ; Wed, 20 Jul 2016 17:04:19 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 067F727D29 for ; Wed, 20 Jul 2016 17:04:19 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EFAC627CE5; Wed, 20 Jul 2016 17:04:18 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F2CD627D64 for ; Wed, 20 Jul 2016 17:04:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754772AbcGTREF (ORCPT ); Wed, 20 Jul 2016 13:04:05 -0400 Received: from foss.arm.com ([217.140.101.70]:43658 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754403AbcGTRD5 (ORCPT ); Wed, 20 Jul 2016 13:03:57 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4DB26959; Wed, 20 Jul 2016 10:05:07 -0700 (PDT) Received: from e104803-lin.lan (unknown [10.1.207.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9AC573F387; Wed, 20 Jul 2016 10:03:55 -0700 (PDT) From: Andre Przywara To: Will Deacon , Marc Zyngier Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v7 05/15] virtio: fix endianness check for vhost support Date: Wed, 20 Jul 2016 18:04:25 +0100 Message-Id: <20160720170435.28090-6-andre.przywara@arm.com> X-Mailer: git-send-email 2.9.0 In-Reply-To: <20160720170435.28090-1-andre.przywara@arm.com> References: <20160720170435.28090-1-andre.przywara@arm.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Currently we deny any VHOST_* functionality if the architecture supports guests with different endianness than the host. Most of the time even on those architectures the endianness of guest and host are the same, though, so we are denying the glory of VHOST needlessly. Switch from compile time determination to a run time scheme, which takes the actual endianness of the guest into account. For this we change the semantics of VIRTIO_ENDIAN_HOST to return the actual endianness of the host (the endianness of kvmtool at compile time, really). The actual check in vhost_net now compares this against the guest endianness. This enables vhost support on ARM and ARM64. Signed-off-by: Andre Przywara --- include/kvm/virtio.h | 9 +++++++-- virtio/net.c | 2 +- 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/include/kvm/virtio.h b/include/kvm/virtio.h index 768ee96..66530fd 100644 --- a/include/kvm/virtio.h +++ b/include/kvm/virtio.h @@ -17,10 +17,15 @@ #define VIRTIO_PCI_O_CONFIG 0 #define VIRTIO_PCI_O_MSIX 1 -#define VIRTIO_ENDIAN_HOST 0 #define VIRTIO_ENDIAN_LE (1 << 0) #define VIRTIO_ENDIAN_BE (1 << 1) +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ +#define VIRTIO_ENDIAN_HOST VIRTIO_ENDIAN_LE +#else +#define VIRTIO_ENDIAN_HOST VIRTIO_ENDIAN_BE +#endif + struct virt_queue { struct vring vring; u32 pfn; @@ -40,7 +45,7 @@ struct virt_queue { #define VIRTIO_RING_ENDIAN VIRTIO_ENDIAN_HOST #endif -#if (VIRTIO_RING_ENDIAN & (VIRTIO_ENDIAN_LE | VIRTIO_ENDIAN_BE)) +#if VIRTIO_RING_ENDIAN != VIRTIO_ENDIAN_HOST static inline __u16 __virtio_g2h_u16(u16 endian, __u16 val) { diff --git a/virtio/net.c b/virtio/net.c index 6d1be65..e94e37a 100644 --- a/virtio/net.c +++ b/virtio/net.c @@ -531,7 +531,7 @@ static int init_vq(struct kvm *kvm, void *dev, u32 vq, u32 page_size, u32 align, } if (queue->endian != VIRTIO_ENDIAN_HOST) - die_perror("VHOST requires VIRTIO_ENDIAN_HOST"); + die_perror("VHOST requires the same endianness in guest and host"); state.num = queue->vring.num; r = ioctl(ndev->vhost_fd, VHOST_SET_VRING_NUM, &state);