From 25bd55bbabd8957693c1ffc2fe1bf16cb4fdabd4 Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Fri, 24 Apr 2015 14:24:38 +0200 Subject: tun: add tun_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/tun.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'drivers/net') diff --git a/drivers/net/tun.c b/drivers/net/tun.c index e470ae5..301e87c 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -206,14 +206,19 @@ struct tun_struct { u32 flow_count; }; +static inline bool tun_is_little_endian(struct tun_struct *tun) +{ + return tun->flags & TUN_VNET_LE; +} + static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val) { - return __virtio16_to_cpu(tun->flags & TUN_VNET_LE, val); + return __virtio16_to_cpu(tun_is_little_endian(tun), val); } static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val) { - return __cpu_to_virtio16(tun->flags & TUN_VNET_LE, val); + return __cpu_to_virtio16(tun_is_little_endian(tun), val); } static inline u32 tun_hashfn(u32 rxhash) -- cgit v1.1 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') diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 8c350c5..4fdb881 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 v1.1 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 ++- 2 files changed, 4 insertions(+), 2 deletions(-) (limited to 'drivers/net') diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 4fdb881..072ccba 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 301e87c..b210139 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) -- cgit v1.1 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 ++++++++++++++++++++++++++++++++++++++++++++++++++- 3 files changed, 128 insertions(+), 2 deletions(-) (limited to 'drivers/net') diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index df51d60..71ac0ec 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 072ccba..928f3f4 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 b210139..cb376b2d 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; -- cgit v1.1