| Message ID | 1436766411-29144-5-git-send-email-jasowang@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 13/07/2015 07:46, Jason Wang wrote: > - if (out_sg[0].iov_len < n->guest_hdr_len) { > + s = iov_to_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); > + if (s != sizeof(hdr)) { > error_report("virtio-net header incorrect"); > exit(1); > } > - virtio_net_hdr_swap(vdev, (void *) out_sg[0].iov_base); > + virtio_net_hdr_swap(vdev, (void *) &hdr); > + s = iov_from_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); > + assert(s == sizeof(hdr)); > } Are the copies necessary in the common case of no swap? In that case you can just use iov_size. Paolo
On Mon, Jul 13, 2015 at 01:46:51PM +0800, Jason Wang wrote: > Commit 032a74a1c0fcdd5fd1c69e56126b4c857ee36611 > ("virtio-net: byteswap virtio-net header") breaks any layout by > requiring out_sg[0].iov_len >= n->guest_hdr_len. Fixing this by > copying header to temporary buffer and copying it back after byteswap. > > Fixes 032a74a1c0fcdd5fd1c69e56126b4c857ee36611 > ("virtio-net: byteswap virtio-net header") > Cc: qemu-stable@nongnu.org > Cc: clg@fr.ibm.com > Signed-off-by: Jason Wang <jasowang@redhat.com> > --- > hw/net/virtio-net.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > index e3c2db3..b42af8f 100644 > --- a/hw/net/virtio-net.c > +++ b/hw/net/virtio-net.c > @@ -1139,10 +1139,11 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) > } > > while (virtqueue_pop(q->tx_vq, &elem)) { > - ssize_t ret, len; > + ssize_t ret, len, s; > unsigned int out_num = elem.out_num; > struct iovec *out_sg = &elem.out_sg[0]; > struct iovec sg[VIRTQUEUE_MAX_SIZE]; > + struct virtio_net_hdr hdr; > > if (out_num < 1) { > error_report("virtio-net header not in first element"); > @@ -1150,11 +1151,14 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) > } > > if (n->has_vnet_hdr) { > - if (out_sg[0].iov_len < n->guest_hdr_len) { > + s = iov_to_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); > + if (s != sizeof(hdr)) { > error_report("virtio-net header incorrect"); > exit(1); > } > - virtio_net_hdr_swap(vdev, (void *) out_sg[0].iov_base); > + virtio_net_hdr_swap(vdev, (void *) &hdr); > + s = iov_from_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); > + assert(s == sizeof(hdr)); > } > > /* Looks like this will write into out_sg - that's violating the virtio spec. > -- > 2.1.4
On Mon, Jul 13, 2015 at 10:24:59AM +0300, Michael S. Tsirkin wrote: > On Mon, Jul 13, 2015 at 01:46:51PM +0800, Jason Wang wrote: > > Commit 032a74a1c0fcdd5fd1c69e56126b4c857ee36611 > > ("virtio-net: byteswap virtio-net header") breaks any layout by > > requiring out_sg[0].iov_len >= n->guest_hdr_len. Fixing this by > > copying header to temporary buffer and copying it back after byteswap. > > > > Fixes 032a74a1c0fcdd5fd1c69e56126b4c857ee36611 > > ("virtio-net: byteswap virtio-net header") > > Cc: qemu-stable@nongnu.org > > Cc: clg@fr.ibm.com > > Signed-off-by: Jason Wang <jasowang@redhat.com> > > --- > > hw/net/virtio-net.c | 10 +++++++--- > > 1 file changed, 7 insertions(+), 3 deletions(-) > > > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > > index e3c2db3..b42af8f 100644 > > --- a/hw/net/virtio-net.c > > +++ b/hw/net/virtio-net.c > > @@ -1139,10 +1139,11 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) > > } > > > > while (virtqueue_pop(q->tx_vq, &elem)) { > > - ssize_t ret, len; > > + ssize_t ret, len, s; > > unsigned int out_num = elem.out_num; > > struct iovec *out_sg = &elem.out_sg[0]; > > struct iovec sg[VIRTQUEUE_MAX_SIZE]; > > + struct virtio_net_hdr hdr; > > > > if (out_num < 1) { > > error_report("virtio-net header not in first element"); > > @@ -1150,11 +1151,14 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) > > } > > > > if (n->has_vnet_hdr) { > > - if (out_sg[0].iov_len < n->guest_hdr_len) { > > + s = iov_to_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); > > + if (s != sizeof(hdr)) { > > error_report("virtio-net header incorrect"); > > exit(1); > > } > > - virtio_net_hdr_swap(vdev, (void *) out_sg[0].iov_base); > > + virtio_net_hdr_swap(vdev, (void *) &hdr); > > + s = iov_from_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); > > + assert(s == sizeof(hdr)); > > } > > > > /* > > Looks like this will write into out_sg - that's violating the virtio spec. And the fault lies with the original code upstream - not with these patches. In my opinion the thing to do here is to completely avoid using vnet header for cross endian unless host supports ioctls to set endian-ness. > > -- > > 2.1.4
On 07/13/2015 02:50 PM, Paolo Bonzini wrote: > > On 13/07/2015 07:46, Jason Wang wrote: >> - if (out_sg[0].iov_len < n->guest_hdr_len) { >> + s = iov_to_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); >> + if (s != sizeof(hdr)) { >> error_report("virtio-net header incorrect"); >> exit(1); >> } >> - virtio_net_hdr_swap(vdev, (void *) out_sg[0].iov_base); >> + virtio_net_hdr_swap(vdev, (void *) &hdr); >> + s = iov_from_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); >> + assert(s == sizeof(hdr)); >> } > Are the copies necessary in the common case of no swap? In that case > you can just use iov_size. > > Paolo > Not necessary, will fix this in V2. Thanks
On 07/13/2015 03:24 PM, Michael S. Tsirkin wrote: > On Mon, Jul 13, 2015 at 01:46:51PM +0800, Jason Wang wrote: >> Commit 032a74a1c0fcdd5fd1c69e56126b4c857ee36611 >> ("virtio-net: byteswap virtio-net header") breaks any layout by >> requiring out_sg[0].iov_len >= n->guest_hdr_len. Fixing this by >> copying header to temporary buffer and copying it back after byteswap. >> >> Fixes 032a74a1c0fcdd5fd1c69e56126b4c857ee36611 >> ("virtio-net: byteswap virtio-net header") >> Cc: qemu-stable@nongnu.org >> Cc: clg@fr.ibm.com >> Signed-off-by: Jason Wang <jasowang@redhat.com> >> --- >> hw/net/virtio-net.c | 10 +++++++--- >> 1 file changed, 7 insertions(+), 3 deletions(-) >> >> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c >> index e3c2db3..b42af8f 100644 >> --- a/hw/net/virtio-net.c >> +++ b/hw/net/virtio-net.c >> @@ -1139,10 +1139,11 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) >> } >> >> while (virtqueue_pop(q->tx_vq, &elem)) { >> - ssize_t ret, len; >> + ssize_t ret, len, s; >> unsigned int out_num = elem.out_num; >> struct iovec *out_sg = &elem.out_sg[0]; >> struct iovec sg[VIRTQUEUE_MAX_SIZE]; >> + struct virtio_net_hdr hdr; >> >> if (out_num < 1) { >> error_report("virtio-net header not in first element"); >> @@ -1150,11 +1151,14 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) >> } >> >> if (n->has_vnet_hdr) { >> - if (out_sg[0].iov_len < n->guest_hdr_len) { >> + s = iov_to_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); >> + if (s != sizeof(hdr)) { >> error_report("virtio-net header incorrect"); >> exit(1); >> } >> - virtio_net_hdr_swap(vdev, (void *) out_sg[0].iov_base); >> + virtio_net_hdr_swap(vdev, (void *) &hdr); >> + s = iov_from_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); >> + assert(s == sizeof(hdr)); >> } >> >> /* > Looks like this will write into out_sg - that's violating the virtio spec. Right, will fix this in V2. Thanks > >> -- >> 2.1.4
On Mon, 13 Jul 2015 11:22:09 +0300 "Michael S. Tsirkin" <mst@redhat.com> wrote: > On Mon, Jul 13, 2015 at 10:24:59AM +0300, Michael S. Tsirkin wrote: > > On Mon, Jul 13, 2015 at 01:46:51PM +0800, Jason Wang wrote: > > > Commit 032a74a1c0fcdd5fd1c69e56126b4c857ee36611 > > > ("virtio-net: byteswap virtio-net header") breaks any layout by > > > requiring out_sg[0].iov_len >= n->guest_hdr_len. Fixing this by > > > copying header to temporary buffer and copying it back after byteswap. > > > > > > Fixes 032a74a1c0fcdd5fd1c69e56126b4c857ee36611 > > > ("virtio-net: byteswap virtio-net header") > > > Cc: qemu-stable@nongnu.org > > > Cc: clg@fr.ibm.com > > > Signed-off-by: Jason Wang <jasowang@redhat.com> > > > --- > > > hw/net/virtio-net.c | 10 +++++++--- > > > 1 file changed, 7 insertions(+), 3 deletions(-) > > > > > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > > > index e3c2db3..b42af8f 100644 > > > --- a/hw/net/virtio-net.c > > > +++ b/hw/net/virtio-net.c > > > @@ -1139,10 +1139,11 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) > > > } > > > > > > while (virtqueue_pop(q->tx_vq, &elem)) { > > > - ssize_t ret, len; > > > + ssize_t ret, len, s; > > > unsigned int out_num = elem.out_num; > > > struct iovec *out_sg = &elem.out_sg[0]; > > > struct iovec sg[VIRTQUEUE_MAX_SIZE]; > > > + struct virtio_net_hdr hdr; > > > > > > if (out_num < 1) { > > > error_report("virtio-net header not in first element"); > > > @@ -1150,11 +1151,14 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) > > > } > > > > > > if (n->has_vnet_hdr) { > > > - if (out_sg[0].iov_len < n->guest_hdr_len) { > > > + s = iov_to_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); > > > + if (s != sizeof(hdr)) { > > > error_report("virtio-net header incorrect"); > > > exit(1); > > > } > > > - virtio_net_hdr_swap(vdev, (void *) out_sg[0].iov_base); > > > + virtio_net_hdr_swap(vdev, (void *) &hdr); > > > + s = iov_from_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); > > > + assert(s == sizeof(hdr)); > > > } > > > > > > /* > > > > Looks like this will write into out_sg - that's violating the virtio spec. > > And the fault lies with the original code upstream - not with these > patches. In my opinion the thing to do here is to completely I fully agree: it is a hack. > avoid using vnet header for cross endian unless host supports ioctls > to set endian-ness. > Makes sense. I had an *experimental* patch that would just deactivate the cross-endian hack if the host kernel provides the TUNSETVNETLE/BE ioctls. It worked but the patch was really ugly and I did not care to post at the time... I'll try to work something out before I go on vacation. > > > -- > > > 2.1.4 > Cheers. -- Greg
On Mon, Jul 13, 2015 at 12:54:02PM +0200, Greg Kurz wrote: > On Mon, 13 Jul 2015 11:22:09 +0300 > "Michael S. Tsirkin" <mst@redhat.com> wrote: > > On Mon, Jul 13, 2015 at 10:24:59AM +0300, Michael S. Tsirkin wrote: > > > On Mon, Jul 13, 2015 at 01:46:51PM +0800, Jason Wang wrote: > > > > Commit 032a74a1c0fcdd5fd1c69e56126b4c857ee36611 > > > > ("virtio-net: byteswap virtio-net header") breaks any layout by > > > > requiring out_sg[0].iov_len >= n->guest_hdr_len. Fixing this by > > > > copying header to temporary buffer and copying it back after byteswap. > > > > > > > > Fixes 032a74a1c0fcdd5fd1c69e56126b4c857ee36611 > > > > ("virtio-net: byteswap virtio-net header") > > > > Cc: qemu-stable@nongnu.org > > > > Cc: clg@fr.ibm.com > > > > Signed-off-by: Jason Wang <jasowang@redhat.com> > > > > --- > > > > hw/net/virtio-net.c | 10 +++++++--- > > > > 1 file changed, 7 insertions(+), 3 deletions(-) > > > > > > > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > > > > index e3c2db3..b42af8f 100644 > > > > --- a/hw/net/virtio-net.c > > > > +++ b/hw/net/virtio-net.c > > > > @@ -1139,10 +1139,11 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) > > > > } > > > > > > > > while (virtqueue_pop(q->tx_vq, &elem)) { > > > > - ssize_t ret, len; > > > > + ssize_t ret, len, s; > > > > unsigned int out_num = elem.out_num; > > > > struct iovec *out_sg = &elem.out_sg[0]; > > > > struct iovec sg[VIRTQUEUE_MAX_SIZE]; > > > > + struct virtio_net_hdr hdr; > > > > > > > > if (out_num < 1) { > > > > error_report("virtio-net header not in first element"); > > > > @@ -1150,11 +1151,14 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) > > > > } > > > > > > > > if (n->has_vnet_hdr) { > > > > - if (out_sg[0].iov_len < n->guest_hdr_len) { > > > > + s = iov_to_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); > > > > + if (s != sizeof(hdr)) { > > > > error_report("virtio-net header incorrect"); > > > > exit(1); > > > > } > > > > - virtio_net_hdr_swap(vdev, (void *) out_sg[0].iov_base); > > > > + virtio_net_hdr_swap(vdev, (void *) &hdr); > > > > + s = iov_from_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); > > > > + assert(s == sizeof(hdr)); > > > > } > > > > > > > > /* > > > > > > Looks like this will write into out_sg - that's violating the virtio spec. > > > > And the fault lies with the original code upstream - not with these > > patches. In my opinion the thing to do here is to completely > > I fully agree: it is a hack. > > > avoid using vnet header for cross endian unless host supports ioctls > > to set endian-ness. > > > > Makes sense. I had an *experimental* patch that would just deactivate > the cross-endian hack if the host kernel provides the TUNSETVNETLE/BE > ioctls. It worked but the patch was really ugly and I did not care to > post at the time... So my proposal would be to basically drop the hack completely: if we are cross-endian and TUNSETVNETLE/BE are unavailable, treat it as if has_vnet_hdr was not set. > I'll try to work something out before I go on > vacation. > > > > > -- > > > > 2.1.4 > > > > Cheers. > > -- > Greg
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index e3c2db3..b42af8f 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -1139,10 +1139,11 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) } while (virtqueue_pop(q->tx_vq, &elem)) { - ssize_t ret, len; + ssize_t ret, len, s; unsigned int out_num = elem.out_num; struct iovec *out_sg = &elem.out_sg[0]; struct iovec sg[VIRTQUEUE_MAX_SIZE]; + struct virtio_net_hdr hdr; if (out_num < 1) { error_report("virtio-net header not in first element"); @@ -1150,11 +1151,14 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) } if (n->has_vnet_hdr) { - if (out_sg[0].iov_len < n->guest_hdr_len) { + s = iov_to_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); + if (s != sizeof(hdr)) { error_report("virtio-net header incorrect"); exit(1); } - virtio_net_hdr_swap(vdev, (void *) out_sg[0].iov_base); + virtio_net_hdr_swap(vdev, (void *) &hdr); + s = iov_from_buf(out_sg, out_num, 0, &hdr, sizeof(hdr)); + assert(s == sizeof(hdr)); } /*
Commit 032a74a1c0fcdd5fd1c69e56126b4c857ee36611 ("virtio-net: byteswap virtio-net header") breaks any layout by requiring out_sg[0].iov_len >= n->guest_hdr_len. Fixing this by copying header to temporary buffer and copying it back after byteswap. Fixes 032a74a1c0fcdd5fd1c69e56126b4c857ee36611 ("virtio-net: byteswap virtio-net header") Cc: qemu-stable@nongnu.org Cc: clg@fr.ibm.com Signed-off-by: Jason Wang <jasowang@redhat.com> --- hw/net/virtio-net.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)