| Message ID | 20150423152712.11795.29245.stgit@bahia.local (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, 23 Apr 2015 17:29:06 +0200 Greg Kurz <gkurz@linux.vnet.ibm.com> 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> > --- > > Changes since v4: > - style fixes (I have chosen if ... else in most places to stay below > 80 columns, with the notable exception of the vhost helper which gets > shorten in a later patch) > > drivers/net/macvtap.c | 5 ++++- > drivers/net/tun.c | 5 ++++- > drivers/vhost/vhost.h | 2 +- > include/linux/virtio_byteorder.h | 24 ++++++++++++++---------- > include/linux/virtio_config.h | 5 ++++- > include/linux/vringh.h | 2 +- > 6 files changed, 28 insertions(+), 15 deletions(-) > > diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c > index a2f2958..6cf6b3e 100644 > --- a/drivers/net/macvtap.c > +++ b/drivers/net/macvtap.c > @@ -51,7 +51,10 @@ 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; > + else > + return virtio_legacy_is_little_endian(); simply: 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 3c3d6c0..5b044d4 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -208,7 +208,10 @@ 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; > + else > + return virtio_legacy_is_little_endian(); dito? > } > > 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..954c657 100644 > --- a/drivers/vhost/vhost.h > +++ b/drivers/vhost/vhost.h > @@ -175,7 +175,7 @@ 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) ? true : virtio_legacy_is_little_endian(); > } That line is way longer than 80 characters ... may I suggest to switch at least here to: return vhost_has_feature(vq, VIRTIO_F_VERSION_1) || virtio_legacy_is_little_endian(); ? Apart from the cosmetics, the patch looks good to me. Thomas -- 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 Thu, 23 Apr 2015 21:27:19 +0200 Thomas Huth <thuth@redhat.com> wrote: > On Thu, 23 Apr 2015 17:29:06 +0200 > Greg Kurz <gkurz@linux.vnet.ibm.com> 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> > > --- > > > > Changes since v4: > > - style fixes (I have chosen if ... else in most places to stay below > > 80 columns, with the notable exception of the vhost helper which gets > > shorten in a later patch) > > > > drivers/net/macvtap.c | 5 ++++- > > drivers/net/tun.c | 5 ++++- > > drivers/vhost/vhost.h | 2 +- > > include/linux/virtio_byteorder.h | 24 ++++++++++++++---------- > > include/linux/virtio_config.h | 5 ++++- > > include/linux/vringh.h | 2 +- > > 6 files changed, 28 insertions(+), 15 deletions(-) > > > > diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c > > index a2f2958..6cf6b3e 100644 > > --- a/drivers/net/macvtap.c > > +++ b/drivers/net/macvtap.c > > @@ -51,7 +51,10 @@ 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; > > + else > > + return virtio_legacy_is_little_endian(); > > simply: > > return (q->flags & MACVTAP_VNET_LE) || > virtio_legacy_is_little_endian(); > > ? ISTR that MST preferred the current notation, but I like either your way or ?: (with linebreak) even better. > > > } > > (...) > > diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h > > index 6a49960..954c657 100644 > > --- a/drivers/vhost/vhost.h > > +++ b/drivers/vhost/vhost.h > > @@ -175,7 +175,7 @@ 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) ? true : virtio_legacy_is_little_endian(); > > } > > That line is way longer than 80 characters ... may I suggest to switch > at least here to: > > return vhost_has_feature(vq, VIRTIO_F_VERSION_1) || > virtio_legacy_is_little_endian(); I think the line will collapse in a further patch anyway. -- 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 Fri, 24 Apr 2015 09:04:21 +0200 Cornelia Huck <cornelia.huck@de.ibm.com> wrote: > On Thu, 23 Apr 2015 21:27:19 +0200 > Thomas Huth <thuth@redhat.com> wrote: > Thomas's e-mail did not make it to my mailbox... weird. :-\ > > On Thu, 23 Apr 2015 17:29:06 +0200 > > Greg Kurz <gkurz@linux.vnet.ibm.com> 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> > > > --- > > > > > > Changes since v4: > > > - style fixes (I have chosen if ... else in most places to stay below > > > 80 columns, with the notable exception of the vhost helper which gets > > > shorten in a later patch) > > > > > > drivers/net/macvtap.c | 5 ++++- > > > drivers/net/tun.c | 5 ++++- > > > drivers/vhost/vhost.h | 2 +- > > > include/linux/virtio_byteorder.h | 24 ++++++++++++++---------- > > > include/linux/virtio_config.h | 5 ++++- > > > include/linux/vringh.h | 2 +- > > > 6 files changed, 28 insertions(+), 15 deletions(-) > > > > > > diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c > > > index a2f2958..6cf6b3e 100644 > > > --- a/drivers/net/macvtap.c > > > +++ b/drivers/net/macvtap.c > > > @@ -51,7 +51,10 @@ 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; > > > + else > > > + return virtio_legacy_is_little_endian(); > > > > simply: > > > > return (q->flags & MACVTAP_VNET_LE) || > > virtio_legacy_is_little_endian(); > > > > ? > > ISTR that MST preferred the current notation, but I like either your > way or ?: (with linebreak) even better. > MST did not like the initial notation I had used actually. FWIW I like the simplicity of Thomas's suggestion... even better than ?: which is: some_LE_check() ? true : some_default_endianness() > > > > > } > > > > (...) > > > diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h > > > index 6a49960..954c657 100644 > > > --- a/drivers/vhost/vhost.h > > > +++ b/drivers/vhost/vhost.h > > > @@ -175,7 +175,7 @@ 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) ? true : virtio_legacy_is_little_endian(); > > > } > > > > That line is way longer than 80 characters ... may I suggest to switch > > at least here to: > > > > return vhost_has_feature(vq, VIRTIO_F_VERSION_1) || > > virtio_legacy_is_little_endian(); > > I think the line will collapse in a further patch anyway. > Yes, as mentionned in the changelog :) > -- > 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 > -- 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..6cf6b3e 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -51,7 +51,10 @@ 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; + else + 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..5b044d4 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -208,7 +208,10 @@ 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; + else + 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..954c657 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -175,7 +175,7 @@ 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) ? true : 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..743e24c 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -207,7 +207,10 @@ 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; + else + return virtio_legacy_is_little_endian(); } /* Memory accessors */ diff --git a/include/linux/vringh.h b/include/linux/vringh.h index 3ed62ef..d070bbcd 100644 --- a/include/linux/vringh.h +++ b/include/linux/vringh.h @@ -228,7 +228,7 @@ 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 ? true : 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> --- Changes since v4: - style fixes (I have chosen if ... else in most places to stay below 80 columns, with the notable exception of the vhost helper which gets shorten in a later patch) drivers/net/macvtap.c | 5 ++++- drivers/net/tun.c | 5 ++++- drivers/vhost/vhost.h | 2 +- include/linux/virtio_byteorder.h | 24 ++++++++++++++---------- include/linux/virtio_config.h | 5 ++++- include/linux/vringh.h | 2 +- 6 files changed, 28 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