Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932921AbbDJKUd (ORCPT ); Fri, 10 Apr 2015 06:20:33 -0400 Received: from e06smtp13.uk.ibm.com ([195.75.94.109]:43666 "EHLO e06smtp13.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932856AbbDJKU1 (ORCPT ); Fri, 10 Apr 2015 06:20:27 -0400 Subject: [PATCH v4 8/8] macvtap/tun: add VNET_BE flag From: Greg Kurz To: Rusty Russell , "Michael S. Tsirkin" Cc: Cornelia Huck , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Date: Fri, 10 Apr 2015 12:20:21 +0200 Message-ID: <20150410101923.31843.66853.stgit@bahia.local> In-Reply-To: <20150410101500.31843.61248.stgit@bahia.local> References: <20150410101500.31843.61248.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: 15041010-0013-0000-0000-0000039958EC Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6806 Lines: 251 The VNET_LE flag was introduced to fix accesses to virtio 1.0 headers that are always little-endian. It can also be used to handle the special case of a legacy little-endian device implemented by a big-endian host. Let's add a flag and ioctls for big-endian devices as well. If both flags are set, little-endian wins. Since this is isn't a common usecase, the feature is controlled by a kernel config option (not set by default). Both macvtap and tun are covered by this patch since they share the same API with userland. Signed-off-by: Greg Kurz --- drivers/net/Kconfig | 12 ++++++++ drivers/net/macvtap.c | 60 +++++++++++++++++++++++++++++++++++++++++- drivers/net/tun.c | 62 ++++++++++++++++++++++++++++++++++++++++++- include/uapi/linux/if_tun.h | 2 + 4 files changed, 134 insertions(+), 2 deletions(-) diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index df51d60..f0e23a0 100644 --- a/drivers/net/Kconfig +++ b/drivers/net/Kconfig @@ -244,6 +244,18 @@ config TUN If you don't know what to use this for, you don't need it. +config TUN_VNET_BE + bool "Support for big-endian vnet headers" + default n + ---help--- + This option allows TUN/TAP and MACVTAP device drivers to parse + vnet headers that are in big-endian byte order. It is useful + when the headers come from a big-endian legacy virtio driver and + the host is little-endian. + + Unless you have a little-endian system hosting a big-endian virtual + machine with a virtio NIC, you should say N. + config VETH tristate "Virtual ethernet pair device" ---help--- diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 0a03a66..e0ab1b7 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -48,12 +48,27 @@ struct macvtap_queue { #define MACVTAP_FEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE) #define MACVTAP_VNET_LE 0x80000000 +#define MACVTAP_VNET_BE 0x40000000 + +#ifdef CONFIG_TUN_VNET_BE +static inline bool macvtap_legacy_is_little_endian(struct macvtap_queue *q) +{ + if (q->flags & MACVTAP_VNET_BE) + return false; + return virtio_legacy_is_little_endian(); +} +#else +static inline bool macvtap_legacy_is_little_endian(struct macvtap_queue *q) +{ + return virtio_legacy_is_little_endian(); +} +#endif static inline bool macvtap_is_little_endian(struct macvtap_queue *q) { if (q->flags & MACVTAP_VNET_LE) return true; - return virtio_legacy_is_little_endian(); + return macvtap_legacy_is_little_endian(q); } static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val) @@ -1000,6 +1015,43 @@ static int set_offload(struct macvtap_queue *q, unsigned long arg) return 0; } +#ifdef CONFIG_TUN_VNET_BE +static long macvtap_get_vnet_be(struct macvtap_queue *q, int __user *sp) +{ + int s = !!(q->flags & MACVTAP_VNET_BE); + + if (put_user(s, sp)) + return -EFAULT; + + return 0; +} + +static long macvtap_set_vnet_be(struct macvtap_queue *q, int __user *sp) +{ + int s; + + if (get_user(s, sp)) + return -EFAULT; + + if (s) + q->flags |= MACVTAP_VNET_BE; + else + q->flags &= ~MACVTAP_VNET_BE; + + return 0; +} +#else +static long macvtap_get_vnet_be(struct macvtap_queue *q, int __user *argp) +{ + return -EINVAL; +} + +static long macvtap_set_vnet_be(struct macvtap_queue *q, int __user *argp) +{ + return -EINVAL; +} +#endif /* CONFIG_TUN_VNET_BE */ + /* * provide compatibility with generic tun/tap interface */ @@ -1097,6 +1149,12 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd, q->flags &= ~MACVTAP_VNET_LE; return 0; + case TUNGETVNETBE: + return macvtap_get_vnet_be(q, sp); + + case TUNSETVNETBE: + return macvtap_set_vnet_be(q, sp); + case TUNSETOFFLOAD: /* let the user check for future flags */ if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 | diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 053f9b6..4e12488 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -111,6 +111,7 @@ do { \ #define TUN_FASYNC IFF_ATTACH_QUEUE /* High bits in flags field are unused. */ #define TUN_VNET_LE 0x80000000 +#define TUN_VNET_BE 0x40000000 #define TUN_FEATURES (IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR | \ IFF_MULTI_QUEUE) @@ -206,11 +207,25 @@ struct tun_struct { u32 flow_count; }; +#ifdef CONFIG_TUN_VNET_BE +static inline bool tun_legacy_is_little_endian(struct tun_struct *tun) +{ + if (tun->flags & TUN_VNET_BE) + return false; + return virtio_legacy_is_little_endian(); +} +#else +static inline bool tun_legacy_is_little_endian(struct tun_struct *tun) +{ + return virtio_legacy_is_little_endian(); +} +#endif + static inline bool tun_is_little_endian(struct tun_struct *tun) { if (tun->flags & TUN_VNET_LE) return true; - return virtio_legacy_is_little_endian(); + return tun_legacy_is_little_endian(tun); } static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val) @@ -1836,6 +1851,43 @@ unlock: return ret; } +#ifdef CONFIG_TUN_VNET_BE +static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp) +{ + int be = !!(tun->flags & TUN_VNET_BE); + + if (put_user(be, argp)) + return EFAULT; + + return 0; +} + +static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp) +{ + int be; + + if (get_user(be, argp)) + return -EFAULT; + + if (be) + tun->flags |= TUN_VNET_BE; + else + tun->flags &= ~TUN_VNET_BE; + + return 0; +} +#else +static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp) +{ + return -EINVAL; +} + +static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp) +{ + return -EINVAL; +} +#endif /* CONFIG_TUN_VNET_BE */ + static long __tun_chr_ioctl(struct file *file, unsigned int cmd, unsigned long arg, int ifreq_len) { @@ -2065,6 +2117,14 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, tun->flags &= ~TUN_VNET_LE; break; + case TUNGETVNETBE: + ret = tun_get_vnet_be(tun, argp); + break; + + case TUNSETVNETBE: + ret = tun_set_vnet_be(tun, argp); + break; + case TUNATTACHFILTER: /* Can be set only for TAPs */ ret = -EINVAL; diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h index 50ae243..bcac4c0 100644 --- a/include/uapi/linux/if_tun.h +++ b/include/uapi/linux/if_tun.h @@ -50,6 +50,8 @@ #define TUNGETFILTER _IOR('T', 219, struct sock_fprog) #define TUNSETVNETLE _IOW('T', 220, int) #define TUNGETVNETLE _IOR('T', 221, int) +#define TUNSETVNETBE _IOW('T', 222, int) +#define TUNGETVNETBE _IOR('T', 223, int) /* TUNSETIFF ifr flags */ #define IFF_TUN 0x0001 -- 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/