| Message ID | 20150407121533.4213.46434.stgit@bahia.lab.toulouse-stg.fr.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Apr 07, 2015 at 02:15:52PM +0200, Greg Kurz wrote: > 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 <gkurz@linux.vnet.ibm.com> > --- > drivers/net/macvtap.c | 4 +++- > drivers/net/tun.c | 4 +++- > drivers/vhost/vhost.h | 4 +++- > include/linux/virtio_byteorder.h | 24 ++++++++++++++---------- > include/linux/virtio_config.h | 4 +++- > include/linux/vringh.h | 4 +++- > 6 files changed, 29 insertions(+), 15 deletions(-) > > diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c > index a2f2958..0a03a66 100644 > --- a/drivers/net/macvtap.c > +++ b/drivers/net/macvtap.c > @@ -51,7 +51,9 @@ struct macvtap_queue { > > static inline bool macvtap_is_little_endian(struct macvtap_queue *q) > { > - return q->flags & MACVTAP_VNET_LE; > + if (q->flags & MACVTAP_VNET_LE) > + return true; > + return virtio_legacy_is_little_endian(); > } > > static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val) Hmm I'm not sure how well this will work once you actually make it dynamic. Remains to be seen. > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 3c3d6c0..053f9b6 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -208,7 +208,9 @@ struct tun_struct { > > static inline bool tun_is_little_endian(struct tun_struct *tun) > { > - return tun->flags & TUN_VNET_LE; > + if (tun->flags & TUN_VNET_LE) > + return true; > + return 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 6a49960..4e9a186 100644 > --- a/drivers/vhost/vhost.h > +++ b/drivers/vhost/vhost.h > @@ -175,7 +175,9 @@ 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); > + if (vhost_has_feature(vq, VIRTIO_F_VERSION_1)) > + return true; > + return virtio_legacy_is_little_endian(); > } > > /* Memory accessors */ > diff --git a/include/linux/virtio_byteorder.h b/include/linux/virtio_byteorder.h > index 51865d0..ce63a2c 100644 > --- a/include/linux/virtio_byteorder.h > +++ b/include/linux/virtio_byteorder.h > @@ -3,17 +3,21 @@ > #include <linux/types.h> > #include <uapi/linux/virtio_types.h> > > -/* > - * 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 bd1a582..36a6daa 100644 > --- a/include/linux/virtio_config.h > +++ b/include/linux/virtio_config.h > @@ -207,7 +207,9 @@ 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); > + if (virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) > + return true; > + return virtio_legacy_is_little_endian(); > } > > /* Memory accessors */ > diff --git a/include/linux/vringh.h b/include/linux/vringh.h > index 3ed62ef..d786c2d 100644 > --- a/include/linux/vringh.h > +++ b/include/linux/vringh.h > @@ -228,7 +228,9 @@ static inline void vringh_notify(struct vringh *vrh) > > static inline bool vringh_is_little_endian(const struct vringh *vrh) > { > - return vrh->little_endian; > + if (vrh->little_endian) > + return true; > + return virtio_legacy_is_little_endian(); > } > > static inline u16 vringh16_to_cpu(const struct vringh *vrh, __virtio16 val) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, 7 Apr 2015 17:56:25 +0200 "Michael S. Tsirkin" <mst@redhat.com> wrote: > On Tue, Apr 07, 2015 at 02:15:52PM +0200, Greg Kurz wrote: > > 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 <gkurz@linux.vnet.ibm.com> > > --- > > drivers/net/macvtap.c | 4 +++- > > drivers/net/tun.c | 4 +++- > > drivers/vhost/vhost.h | 4 +++- > > include/linux/virtio_byteorder.h | 24 ++++++++++++++---------- > > include/linux/virtio_config.h | 4 +++- > > include/linux/vringh.h | 4 +++- > > 6 files changed, 29 insertions(+), 15 deletions(-) > > > > diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c > > index a2f2958..0a03a66 100644 > > --- a/drivers/net/macvtap.c > > +++ b/drivers/net/macvtap.c > > @@ -51,7 +51,9 @@ struct macvtap_queue { > > > > static inline bool macvtap_is_little_endian(struct macvtap_queue *q) > > { > > - return q->flags & MACVTAP_VNET_LE; > > + if (q->flags & MACVTAP_VNET_LE) > > + return true; > > + return virtio_legacy_is_little_endian(); > > } > > > > static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val) > > Hmm I'm not sure how well this will work once you > actually make it dynamic. > Remains to be seen. > Oops I overlooked this mail... FWIW I could reboot/kexec from a ppc64 guest to ppc64le and back with the following QEMU: https://github.com/gkurz/qemu/commits/vhost/cross-endian > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > > index 3c3d6c0..053f9b6 100644 > > --- a/drivers/net/tun.c > > +++ b/drivers/net/tun.c > > @@ -208,7 +208,9 @@ struct tun_struct { > > > > static inline bool tun_is_little_endian(struct tun_struct *tun) > > { > > - return tun->flags & TUN_VNET_LE; > > + if (tun->flags & TUN_VNET_LE) > > + return true; > > + return 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 6a49960..4e9a186 100644 > > --- a/drivers/vhost/vhost.h > > +++ b/drivers/vhost/vhost.h > > @@ -175,7 +175,9 @@ 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); > > + if (vhost_has_feature(vq, VIRTIO_F_VERSION_1)) > > + return true; > > + return virtio_legacy_is_little_endian(); > > } > > > > /* Memory accessors */ > > diff --git a/include/linux/virtio_byteorder.h b/include/linux/virtio_byteorder.h > > index 51865d0..ce63a2c 100644 > > --- a/include/linux/virtio_byteorder.h > > +++ b/include/linux/virtio_byteorder.h > > @@ -3,17 +3,21 @@ > > #include <linux/types.h> > > #include <uapi/linux/virtio_types.h> > > > > -/* > > - * 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 bd1a582..36a6daa 100644 > > --- a/include/linux/virtio_config.h > > +++ b/include/linux/virtio_config.h > > @@ -207,7 +207,9 @@ 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); > > + if (virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) > > + return true; > > + return virtio_legacy_is_little_endian(); > > } > > > > /* Memory accessors */ > > diff --git a/include/linux/vringh.h b/include/linux/vringh.h > > index 3ed62ef..d786c2d 100644 > > --- a/include/linux/vringh.h > > +++ b/include/linux/vringh.h > > @@ -228,7 +228,9 @@ static inline void vringh_notify(struct vringh *vrh) > > > > static inline bool vringh_is_little_endian(const struct vringh *vrh) > > { > > - return vrh->little_endian; > > + if (vrh->little_endian) > > + return true; > > + return virtio_legacy_is_little_endian(); > > } > > > > static inline u16 vringh16_to_cpu(const struct vringh *vrh, __virtio16 val) > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index a2f2958..0a03a66 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -51,7 +51,9 @@ struct macvtap_queue { static inline bool macvtap_is_little_endian(struct macvtap_queue *q) { - return q->flags & MACVTAP_VNET_LE; + if (q->flags & MACVTAP_VNET_LE) + return true; + return 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 3c3d6c0..053f9b6 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -208,7 +208,9 @@ struct tun_struct { static inline bool tun_is_little_endian(struct tun_struct *tun) { - return tun->flags & TUN_VNET_LE; + if (tun->flags & TUN_VNET_LE) + return true; + return 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 6a49960..4e9a186 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -175,7 +175,9 @@ 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); + if (vhost_has_feature(vq, VIRTIO_F_VERSION_1)) + return true; + return virtio_legacy_is_little_endian(); } /* Memory accessors */ diff --git a/include/linux/virtio_byteorder.h b/include/linux/virtio_byteorder.h index 51865d0..ce63a2c 100644 --- a/include/linux/virtio_byteorder.h +++ b/include/linux/virtio_byteorder.h @@ -3,17 +3,21 @@ #include <linux/types.h> #include <uapi/linux/virtio_types.h> -/* - * 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 bd1a582..36a6daa 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -207,7 +207,9 @@ 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); + if (virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) + return true; + return virtio_legacy_is_little_endian(); } /* Memory accessors */ diff --git a/include/linux/vringh.h b/include/linux/vringh.h index 3ed62ef..d786c2d 100644 --- a/include/linux/vringh.h +++ b/include/linux/vringh.h @@ -228,7 +228,9 @@ static inline void vringh_notify(struct vringh *vrh) static inline bool vringh_is_little_endian(const struct vringh *vrh) { - return vrh->little_endian; + if (vrh->little_endian) + return true; + return virtio_legacy_is_little_endian(); } static inline u16 vringh16_to_cpu(const struct vringh *vrh, __virtio16 val)
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 <gkurz@linux.vnet.ibm.com> --- drivers/net/macvtap.c | 4 +++- drivers/net/tun.c | 4 +++- drivers/vhost/vhost.h | 4 +++- include/linux/virtio_byteorder.h | 24 ++++++++++++++---------- include/linux/virtio_config.h | 4 +++- include/linux/vringh.h | 4 +++- 6 files changed, 29 insertions(+), 15 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html