From 5b11e15f24744d2ea6210451529d2b180337965a Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Fri, 24 Apr 2015 14:24:48 +0200 Subject: macvtap: introduce macvtap_is_little_endian() helper Signed-off-by: Greg Kurz Signed-off-by: Michael S. Tsirkin Acked-by: Cornelia Huck Reviewed-by: David Gibson --- drivers/net/macvtap.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'drivers/net/macvtap.c') diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 8c350c5d54ad..4fdb88102082 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -49,14 +49,19 @@ struct macvtap_queue { #define MACVTAP_VNET_LE 0x80000000 +static inline bool macvtap_is_little_endian(struct macvtap_queue *q) +{ + return q->flags & MACVTAP_VNET_LE; +} + static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val) { - return __virtio16_to_cpu(q->flags & MACVTAP_VNET_LE, val); + return __virtio16_to_cpu(macvtap_is_little_endian(q), val); } static inline __virtio16 cpu_to_macvtap16(struct macvtap_queue *q, u16 val) { - return __cpu_to_virtio16(q->flags & MACVTAP_VNET_LE, val); + return __cpu_to_virtio16(macvtap_is_little_endian(q), val); } static struct proto macvtap_proto = { -- cgit v1.2.3 From 7d82410950aa74adccf035c332e409af2bb93e92 Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Fri, 24 Apr 2015 14:26:24 +0200 Subject: virtio: add explicit big-endian support to memory accessors The current memory accessors logic is: - little endian if little_endian - native endian (i.e. no byteswap) if !little_endian If we want to fully support cross-endian vhost, we also need to be able to convert to big endian. Instead of changing the little_endian argument to some 3-value enum, this patch changes the logic to: - little endian if little_endian - big endian if !little_endian The native endian case is handled by all users with a trivial helper. This patch doesn't change any functionality, nor it does add overhead. Signed-off-by: Greg Kurz Signed-off-by: Michael S. Tsirkin Reviewed-by: Cornelia Huck Reviewed-by: David Gibson --- drivers/net/macvtap.c | 3 ++- drivers/net/tun.c | 3 ++- drivers/vhost/vhost.h | 3 ++- include/linux/virtio_byteorder.h | 24 ++++++++++++++---------- include/linux/virtio_config.h | 3 ++- include/linux/vringh.h | 3 ++- 6 files changed, 24 insertions(+), 15 deletions(-) (limited to 'drivers/net/macvtap.c') diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 4fdb88102082..072ccbaf7c45 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -51,7 +51,8 @@ struct macvtap_queue { static inline bool macvtap_is_little_endian(struct macvtap_queue *q) { - return q->flags & MACVTAP_VNET_LE; + return q->flags & MACVTAP_VNET_LE || + virtio_legacy_is_little_endian(); } static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 301e87c89a9f..b210139bef8f 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -208,7 +208,8 @@ struct tun_struct { static inline bool tun_is_little_endian(struct tun_struct *tun) { - return tun->flags & TUN_VNET_LE; + return tun->flags & TUN_VNET_LE || + virtio_legacy_is_little_endian(); } static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val) diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 6a499603d856..a4fa33a79bf2 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -175,7 +175,8 @@ static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit) static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq) { - return vhost_has_feature(vq, VIRTIO_F_VERSION_1); + return vhost_has_feature(vq, VIRTIO_F_VERSION_1) || + virtio_legacy_is_little_endian(); } /* Memory accessors */ diff --git a/include/linux/virtio_byteorder.h b/include/linux/virtio_byteorder.h index 51865d05b267..ce63a2c3a612 100644 --- a/include/linux/virtio_byteorder.h +++ b/include/linux/virtio_byteorder.h @@ -3,17 +3,21 @@ #include #include -/* - * Low-level memory accessors for handling virtio in modern little endian and in - * compatibility native endian format. - */ +static inline bool virtio_legacy_is_little_endian(void) +{ +#ifdef __LITTLE_ENDIAN + return true; +#else + return false; +#endif +} static inline u16 __virtio16_to_cpu(bool little_endian, __virtio16 val) { if (little_endian) return le16_to_cpu((__force __le16)val); else - return (__force u16)val; + return be16_to_cpu((__force __be16)val); } static inline __virtio16 __cpu_to_virtio16(bool little_endian, u16 val) @@ -21,7 +25,7 @@ static inline __virtio16 __cpu_to_virtio16(bool little_endian, u16 val) if (little_endian) return (__force __virtio16)cpu_to_le16(val); else - return (__force __virtio16)val; + return (__force __virtio16)cpu_to_be16(val); } static inline u32 __virtio32_to_cpu(bool little_endian, __virtio32 val) @@ -29,7 +33,7 @@ static inline u32 __virtio32_to_cpu(bool little_endian, __virtio32 val) if (little_endian) return le32_to_cpu((__force __le32)val); else - return (__force u32)val; + return be32_to_cpu((__force __be32)val); } static inline __virtio32 __cpu_to_virtio32(bool little_endian, u32 val) @@ -37,7 +41,7 @@ static inline __virtio32 __cpu_to_virtio32(bool little_endian, u32 val) if (little_endian) return (__force __virtio32)cpu_to_le32(val); else - return (__force __virtio32)val; + return (__force __virtio32)cpu_to_be32(val); } static inline u64 __virtio64_to_cpu(bool little_endian, __virtio64 val) @@ -45,7 +49,7 @@ static inline u64 __virtio64_to_cpu(bool little_endian, __virtio64 val) if (little_endian) return le64_to_cpu((__force __le64)val); else - return (__force u64)val; + return be64_to_cpu((__force __be64)val); } static inline __virtio64 __cpu_to_virtio64(bool little_endian, u64 val) @@ -53,7 +57,7 @@ static inline __virtio64 __cpu_to_virtio64(bool little_endian, u64 val) if (little_endian) return (__force __virtio64)cpu_to_le64(val); else - return (__force __virtio64)val; + return (__force __virtio64)cpu_to_be64(val); } #endif /* _LINUX_VIRTIO_BYTEORDER */ diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index 170947eb11b5..e5ce8ab0b8b0 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -207,7 +207,8 @@ int virtqueue_set_affinity(struct virtqueue *vq, int cpu) static inline bool virtio_is_little_endian(struct virtio_device *vdev) { - return virtio_has_feature(vdev, VIRTIO_F_VERSION_1); + return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) || + virtio_legacy_is_little_endian(); } /* Memory accessors */ diff --git a/include/linux/vringh.h b/include/linux/vringh.h index 3ed62efc2bc5..bc6c28d04263 100644 --- a/include/linux/vringh.h +++ b/include/linux/vringh.h @@ -228,7 +228,8 @@ static inline void vringh_notify(struct vringh *vrh) static inline bool vringh_is_little_endian(const struct vringh *vrh) { - return vrh->little_endian; + return vrh->little_endian || + virtio_legacy_is_little_endian(); } static inline u16 vringh16_to_cpu(const struct vringh *vrh, __virtio16 val) -- cgit v1.2.3 From 8b8e658b16336f0f50aba733f51db636ef121f50 Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Fri, 24 Apr 2015 14:50:36 +0200 Subject: macvtap/tun: cross-endian support for little-endian hosts 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 Signed-off-by: Michael S. Tsirkin Reviewed-by: David Gibson --- drivers/net/Kconfig | 14 +++++++++++ drivers/net/macvtap.c | 57 ++++++++++++++++++++++++++++++++++++++++++- drivers/net/tun.c | 59 ++++++++++++++++++++++++++++++++++++++++++++- include/uapi/linux/if_tun.h | 6 +++++ 4 files changed, 134 insertions(+), 2 deletions(-) (limited to 'drivers/net/macvtap.c') diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index df51d6025a90..71ac0ece2d75 100644 --- a/drivers/net/Kconfig +++ b/drivers/net/Kconfig @@ -244,6 +244,20 @@ config TUN If you don't know what to use this for, you don't need it. +config TUN_VNET_CROSS_LE + bool "Support for cross-endian vnet headers on little-endian kernels" + default n + ---help--- + This option allows TUN/TAP and MACVTAP device drivers in a + little-endian kernel to parse vnet headers that come from a + big-endian legacy virtio device. + + Userspace programs can control the feature using the TUNSETVNETBE + and TUNGETVNETBE ioctls. + + Unless you have a little-endian system hosting a big-endian virtual + machine with a legacy 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 072ccbaf7c45..928f3f4db629 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -48,11 +48,60 @@ 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_CROSS_LE +static inline bool macvtap_legacy_is_little_endian(struct macvtap_queue *q) +{ + return q->flags & MACVTAP_VNET_BE ? false : + virtio_legacy_is_little_endian(); +} + +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 inline bool macvtap_legacy_is_little_endian(struct macvtap_queue *q) +{ + return virtio_legacy_is_little_endian(); +} + +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_CROSS_LE */ static inline bool macvtap_is_little_endian(struct macvtap_queue *q) { return q->flags & MACVTAP_VNET_LE || - virtio_legacy_is_little_endian(); + macvtap_legacy_is_little_endian(q); } static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val) @@ -1096,6 +1145,12 @@ 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 b210139bef8f..cb376b2d548a 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) @@ -206,10 +207,58 @@ struct tun_struct { u32 flow_count; }; +#ifdef CONFIG_TUN_VNET_CROSS_LE +static inline bool tun_legacy_is_little_endian(struct tun_struct *tun) +{ + return tun->flags & TUN_VNET_BE ? false : + virtio_legacy_is_little_endian(); +} + +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 inline bool tun_legacy_is_little_endian(struct tun_struct *tun) +{ + return virtio_legacy_is_little_endian(); +} + +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_CROSS_LE */ + static inline bool tun_is_little_endian(struct tun_struct *tun) { return tun->flags & TUN_VNET_LE || - virtio_legacy_is_little_endian(); + tun_legacy_is_little_endian(tun); } static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val) @@ -2062,6 +2111,14 @@ 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 50ae24335444..3cb5e1d85ddd 100644 --- a/include/uapi/linux/if_tun.h +++ b/include/uapi/linux/if_tun.h @@ -50,6 +50,12 @@ #define TUNGETFILTER _IOR('T', 219, struct sock_fprog) #define TUNSETVNETLE _IOW('T', 220, int) #define TUNGETVNETLE _IOR('T', 221, int) +/* The TUNSETVNETBE and TUNGETVNETBE ioctls are for cross-endian support on + * little-endian hosts. Not all kernel configurations support them, but all + * configurations that support SET also support GET. + */ +#define TUNSETVNETBE _IOW('T', 222, int) +#define TUNGETVNETBE _IOR('T', 223, int) /* TUNSETIFF ifr flags */ #define IFF_TUN 0x0001 -- cgit v1.2.3