Michael S. Tsirkin
2014-Nov-30 15:11 UTC
[PATCH v7 30/46] vhost/net: force len for TX to host endian
vhost/net keeps a copy of some used ring but (ab)uses length field for internal house-keeping. This works because for tx used length is always 0. Suppress sparse errors: we use native endian-ness internally but never expose it to guest. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Reviewed-by: Jason Wang <jasowang at redhat.com> --- drivers/vhost/net.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 8dae2f7..dce5c58 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -48,15 +48,15 @@ MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" * status internally; used for zerocopy tx only. */ /* Lower device DMA failed */ -#define VHOST_DMA_FAILED_LEN 3 +#define VHOST_DMA_FAILED_LEN ((__force __virtio32)3) /* Lower device DMA done */ -#define VHOST_DMA_DONE_LEN 2 +#define VHOST_DMA_DONE_LEN ((__force __virtio32)2) /* Lower device DMA in progress */ -#define VHOST_DMA_IN_PROGRESS 1 +#define VHOST_DMA_IN_PROGRESS ((__force __virtio32)1) /* Buffer unused */ -#define VHOST_DMA_CLEAR_LEN 0 +#define VHOST_DMA_CLEAR_LEN ((__force __virtio32)0) -#define VHOST_DMA_IS_DONE(len) ((len) >= VHOST_DMA_DONE_LEN) +#define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN) enum { VHOST_NET_FEATURES = VHOST_FEATURES | -- MST
Cornelia Huck
2014-Dec-01 12:20 UTC
[PATCH v7 30/46] vhost/net: force len for TX to host endian
On Sun, 30 Nov 2014 17:11:44 +0200 "Michael S. Tsirkin" <mst at redhat.com> wrote:> vhost/net keeps a copy of some used ring but (ab)uses length > field for internal house-keeping. This works because > for tx used length is always 0. > Suppress sparse errors: we use native endian-ness internally but never > expose it to guest.I admit that I find this patch description hard to read :) "vhost/net keeps a copy of the used ring in host memory but (ab)uses the length field for internal house-keeping. This works because the length in the used ring for tx is always 0. In order to suppress sparse errors, we need to force native endianness." ?> > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > Reviewed-by: Jason Wang <jasowang at redhat.com> > --- > drivers/vhost/net.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c > index 8dae2f7..dce5c58 100644 > --- a/drivers/vhost/net.c > +++ b/drivers/vhost/net.c > @@ -48,15 +48,15 @@ MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" > * status internally; used for zerocopy tx only. > */ > /* Lower device DMA failed */ > -#define VHOST_DMA_FAILED_LEN 3 > +#define VHOST_DMA_FAILED_LEN ((__force __virtio32)3) > /* Lower device DMA done */ > -#define VHOST_DMA_DONE_LEN 2 > +#define VHOST_DMA_DONE_LEN ((__force __virtio32)2) > /* Lower device DMA in progress */ > -#define VHOST_DMA_IN_PROGRESS 1 > +#define VHOST_DMA_IN_PROGRESS ((__force __virtio32)1) > /* Buffer unused */ > -#define VHOST_DMA_CLEAR_LEN 0 > +#define VHOST_DMA_CLEAR_LEN ((__force __virtio32)0) > > -#define VHOST_DMA_IS_DONE(len) ((len) >= VHOST_DMA_DONE_LEN) > +#define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN) > > enum { > VHOST_NET_FEATURES = VHOST_FEATURES |
Michael S. Tsirkin
2014-Dec-01 12:33 UTC
[PATCH v7 30/46] vhost/net: force len for TX to host endian
On Mon, Dec 01, 2014 at 01:20:51PM +0100, Cornelia Huck wrote:> On Sun, 30 Nov 2014 17:11:44 +0200 > "Michael S. Tsirkin" <mst at redhat.com> wrote: > > > vhost/net keeps a copy of some used ring but (ab)uses length > > field for internal house-keeping. This works because > > for tx used length is always 0. > > Suppress sparse errors: we use native endian-ness internally but never > > expose it to guest. > > I admit that I find this patch description hard to read :) > > > "vhost/net keeps a copy of the used ring in host memory but (ab)uses > the length field for internal house-keeping. This works because the > length in the used ring for tx is always 0. In order to suppress sparse > errors, we need to force native endianness." > > ?Yes. Add to this "These values are never exposed to guest."> > > > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > > Reviewed-by: Jason Wang <jasowang at redhat.com> > > --- > > drivers/vhost/net.c | 10 +++++----- > > 1 file changed, 5 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c > > index 8dae2f7..dce5c58 100644 > > --- a/drivers/vhost/net.c > > +++ b/drivers/vhost/net.c > > @@ -48,15 +48,15 @@ MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" > > * status internally; used for zerocopy tx only. > > */ > > /* Lower device DMA failed */ > > -#define VHOST_DMA_FAILED_LEN 3 > > +#define VHOST_DMA_FAILED_LEN ((__force __virtio32)3) > > /* Lower device DMA done */ > > -#define VHOST_DMA_DONE_LEN 2 > > +#define VHOST_DMA_DONE_LEN ((__force __virtio32)2) > > /* Lower device DMA in progress */ > > -#define VHOST_DMA_IN_PROGRESS 1 > > +#define VHOST_DMA_IN_PROGRESS ((__force __virtio32)1) > > /* Buffer unused */ > > -#define VHOST_DMA_CLEAR_LEN 0 > > +#define VHOST_DMA_CLEAR_LEN ((__force __virtio32)0) > > > > -#define VHOST_DMA_IS_DONE(len) ((len) >= VHOST_DMA_DONE_LEN) > > +#define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN) > > > > enum { > > VHOST_NET_FEATURES = VHOST_FEATURES |
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