similar to: [PATCH v2 net 1/3] virtio_net: split out ctrl buffer

When sending control commands, virtio net sets up several buffers for DMA. The buffers are all part of the net device which means it's actually allocated by kvmalloc so in theory (on extreme memory pressure) it's possible to get a vmalloc'ed buffer which on some platforms means we can't DMA there. Fix up by moving the DMA buffers out into a separate structure. Reported-by:

From: "Michael S. Tsirkin" <mst at redhat.com> Once virtio starts using the DMA API, we won't be able to safely DMA from the stack. virtio-net does a couple of config DMA requests from small stack buffers -- switch to using dynamically-allocated memory. This should have no effect on any performance-critical code paths. [I wrote the subject and commit message. mst wrote the

On Tue, Oct 27, 2015 at 10:30:19PM -0700, Andy Lutomirski wrote: > From: Andy Lutomirski <luto at amacapital.net> > > Once virtio starts using the DMA API, we won't be able to safely DMA > from the stack. virtio-net does a couple of config DMA requests > from small stack buffers -- switch to using dynamically-allocated > memory. > > This should have no effect

Am 30.10.2015 um 02:09 schrieb Andy Lutomirski: > From: "Michael S. Tsirkin" <mst at redhat.com> > > Once virtio starts using the DMA API, we won't be able to safely DMA > from the stack. virtio-net does a couple of config DMA requests > from small stack buffers -- switch to using dynamically-allocated > memory. > > This should have no effect on any

From: Andy Lutomirski <luto at amacapital.net> Once virtio starts using the DMA API, we won't be able to safely DMA from the stack. virtio-net does a couple of config DMA requests from small stack buffers -- switch to using dynamically-allocated memory. This should have no effect on any performance-critical code paths. Cc: netdev at vger.kernel.org Cc: "Michael S. Tsirkin"

From: Andy Lutomirski <luto at amacapital.net> Once virtio starts using the DMA API, we won't be able to safely DMA from the stack. virtio-net does a couple of config DMA requests from small stack buffers -- switch to using dynamically-allocated memory. This should have no effect on any performance-critical code paths. Cc: netdev at vger.kernel.org Cc: "Michael S. Tsirkin"

This switches virtio to use the DMA API unconditionally. I'm sure it breaks things, but it seems to work on x86 using virtio-pci, with and without Xen, and using both the modern 1.0 variant and the legacy variant. This appears to work on native and Xen x86_64 using both modern and legacy virtio-pci. It also appears to work on arm and arm64. It definitely won't work as-is on s390x, and

This switches virtio to use the DMA API unconditionally. I'm sure it breaks things, but it seems to work on x86 using virtio-pci, with and without Xen, and using both the modern 1.0 variant and the legacy variant. This appears to work on native and Xen x86_64 using both modern and legacy virtio-pci. It also appears to work on arm and arm64. It definitely won't work as-is on s390x, and

On Mon, Jul 17, 2017 at 08:44:01PM +0800, Jason Wang wrote: > Current XDP implementation want guest offloads feature to be disabled s/want/wants/ > on qemu cli. on the device. > This is inconvenient and means guest can't benefit from > offloads if XDP is not used. This patch tries to address this > limitation by disable disabling > the offloads on demand through control

On Mon, Jul 17, 2017 at 08:44:01PM +0800, Jason Wang wrote: > Current XDP implementation want guest offloads feature to be disabled s/want/wants/ > on qemu cli. on the device. > This is inconvenient and means guest can't benefit from > offloads if XDP is not used. This patch tries to address this > limitation by disable disabling > the offloads on demand through control

On Wed, Jul 19, 2017 at 04:54:49PM +0800, Jason Wang wrote: > Current XDP implementation wants guest offloads feature to be disabled > on device. This is inconvenient and means guest can't benefit from > offloads if XDP is not used. This patch tries to address this > limitation by disabling the offloads on demand through control guest > offloads. Guest offloads will be disabled

On Wed, Jul 19, 2017 at 04:54:49PM +0800, Jason Wang wrote: > Current XDP implementation wants guest offloads feature to be disabled > on device. This is inconvenient and means guest can't benefit from > offloads if XDP is not used. This patch tries to address this > limitation by disabling the offloads on demand through control guest > offloads. Guest offloads will be disabled

Current XDP implementation want guest offloads feature to be disabled on qemu cli. This is inconvenient and means guest can't benefit from offloads if XDP is not used. This patch tries to address this limitation by disable the offloads on demand through control guest offloads. Guest offloads will be disabled and enabled on demand on XDP set. Signed-off-by: Jason Wang <jasowang at

Current XDP implementation wants guest offloads feature to be disabled on device. This is inconvenient and means guest can't benefit from offloads if XDP is not used. This patch tries to address this limitation by disabling the offloads on demand through control guest offloads. Guest offloads will be disabled and enabled on demand on XDP set. Signed-off-by: Jason Wang <jasowang at

On 2017?07?19? 04:07, Michael S. Tsirkin wrote: > On Mon, Jul 17, 2017 at 08:44:01PM +0800, Jason Wang wrote: >> Current XDP implementation want guest offloads feature to be disabled > s/want/wants/ > >> on qemu cli. > on the device. > >> This is inconvenient and means guest can't benefit from >> offloads if XDP is not used. This patch tries to address

Hi: This series brings two optimizations for virtio-net XDP: - avoid reset during XDP set - turn off offloads on demand Changes from V1: - Various tweaks on commit logs and comments - Use virtnet_napi_enable() when enabling NAPI on XDP set - Copy the small buffer packet only if xdp_headroom is smaller than required Please review. Thanks Jason Wang (5): virtio_ring: allow to store zero as

Hi: This series brings two optimizations for virtio-net XDP: - avoid reset during XDP set - turn off offloads on demand Changes from V1: - Various tweaks on commit logs and comments - Use virtnet_napi_enable() when enabling NAPI on XDP set - Copy the small buffer packet only if xdp_headroom is smaller than required Please review. Thanks Jason Wang (5): virtio_ring: allow to store zero as

On Thu, 2016-03-10 at 09:28 -0500, Aaron Conole wrote: > This patch checks the feature bit for the VIRTIO_NET_F_MTU feature. If it > exists, read the advised MTU and use it. > > No proper error handling is provided for the case where a user changes the > negotiated MTU. A future commit will add proper error handling. Instead, a > warning is emitted if the guest changes the

On Thu, 2016-03-10 at 09:28 -0500, Aaron Conole wrote: > This patch checks the feature bit for the VIRTIO_NET_F_MTU feature. If it > exists, read the advised MTU and use it. > > No proper error handling is provided for the case where a user changes the > negotiated MTU. A future commit will add proper error handling. Instead, a > warning is emitted if the guest changes the

On Tue, Mar 15, 2016 at 05:04:13PM -0400, Aaron Conole wrote: > This patch checks the feature bit for the VIRTIO_NET_F_MTU feature. If it > exists, read the advised MTU and use it. > > No proper error handling is provided for the case where a user changes the > negotiated MTU. A future commit will add proper error handling. Instead, a > warning is emitted if the guest changes