| Message ID | 1414571925-16918-2-git-send-email-clg@fr.ibm.com |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Oct 29, 2014 at 09:38:42AM +0100, Cédric Le Goater wrote: > The VHOST_VRING_F_BYTESWAP flag will be used by the host to byteswap > the vring data when the guest and the host have a different endian > order. > > Signed-off-by: Cédric Le Goater <clg@fr.ibm.com> I don't think it's a good API. You should ask for specific header format, not for a swap. > --- > drivers/vhost/vhost.c | 5 ++++- > drivers/vhost/vhost.h | 1 + > include/uapi/linux/vhost.h | 3 +++ > 3 files changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index c90f4374442a..72c21b790ba3 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -199,6 +199,7 @@ static void vhost_vq_reset(struct vhost_dev *dev, > vq->call = NULL; > vq->log_ctx = NULL; > vq->memory = NULL; > + vq->byteswap = 0; > } > > static int vhost_worker(void *data) > @@ -701,7 +702,8 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp) > r = -EFAULT; > break; > } > - if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) { > + if (a.flags & ~(0x1 << VHOST_VRING_F_LOG | > + 0x1 << VHOST_VRING_F_BYTESWAP)) { > r = -EOPNOTSUPP; > break; > } > @@ -747,6 +749,7 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp) > vq->avail = (void __user *)(unsigned long)a.avail_user_addr; > vq->log_addr = a.log_guest_addr; > vq->used = (void __user *)(unsigned long)a.used_user_addr; > + vq->byteswap = !!(a.flags & (0x1 << VHOST_VRING_F_BYTESWAP)); > break; > case VHOST_SET_VRING_KICK: > if (copy_from_user(&f, argp, sizeof f)) { > diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h > index 3eda654b8f5a..ab25b7d0720d 100644 > --- a/drivers/vhost/vhost.h > +++ b/drivers/vhost/vhost.h > @@ -110,6 +110,7 @@ struct vhost_virtqueue { > /* Log write descriptors */ > void __user *log_base; > struct vhost_log *log; > + bool byteswap; > }; > > struct vhost_dev { > diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h > index bb6a5b4cb3c5..6a8c2b325c44 100644 > --- a/include/uapi/linux/vhost.h > +++ b/include/uapi/linux/vhost.h > @@ -34,6 +34,9 @@ struct vhost_vring_addr { > /* Flag values: */ > /* Whether log address is valid. If set enables logging. */ > #define VHOST_VRING_F_LOG 0 > + /* Whether vring memory accesses should be byte-swapped. > + * required when the guest has a different endianness */ > +#define VHOST_VRING_F_BYTESWAP 1 > > /* Start of array of descriptors (virtually contiguous) */ > __u64 desc_user_addr; > -- > 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" 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/vhost/vhost.c b/drivers/vhost/vhost.c index c90f4374442a..72c21b790ba3 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -199,6 +199,7 @@ static void vhost_vq_reset(struct vhost_dev *dev, vq->call = NULL; vq->log_ctx = NULL; vq->memory = NULL; + vq->byteswap = 0; } static int vhost_worker(void *data) @@ -701,7 +702,8 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp) r = -EFAULT; break; } - if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) { + if (a.flags & ~(0x1 << VHOST_VRING_F_LOG | + 0x1 << VHOST_VRING_F_BYTESWAP)) { r = -EOPNOTSUPP; break; } @@ -747,6 +749,7 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp) vq->avail = (void __user *)(unsigned long)a.avail_user_addr; vq->log_addr = a.log_guest_addr; vq->used = (void __user *)(unsigned long)a.used_user_addr; + vq->byteswap = !!(a.flags & (0x1 << VHOST_VRING_F_BYTESWAP)); break; case VHOST_SET_VRING_KICK: if (copy_from_user(&f, argp, sizeof f)) { diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 3eda654b8f5a..ab25b7d0720d 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -110,6 +110,7 @@ struct vhost_virtqueue { /* Log write descriptors */ void __user *log_base; struct vhost_log *log; + bool byteswap; }; struct vhost_dev { diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h index bb6a5b4cb3c5..6a8c2b325c44 100644 --- a/include/uapi/linux/vhost.h +++ b/include/uapi/linux/vhost.h @@ -34,6 +34,9 @@ struct vhost_vring_addr { /* Flag values: */ /* Whether log address is valid. If set enables logging. */ #define VHOST_VRING_F_LOG 0 + /* Whether vring memory accesses should be byte-swapped. + * required when the guest has a different endianness */ +#define VHOST_VRING_F_BYTESWAP 1 /* Start of array of descriptors (virtually contiguous) */ __u64 desc_user_addr;
The VHOST_VRING_F_BYTESWAP flag will be used by the host to byteswap the vring data when the guest and the host have a different endian order. Signed-off-by: Cédric Le Goater <clg@fr.ibm.com> --- drivers/vhost/vhost.c | 5 ++++- drivers/vhost/vhost.h | 1 + include/uapi/linux/vhost.h | 3 +++ 3 files changed, 8 insertions(+), 1 deletion(-)