search for: virtio_f_notify_on_empti

VIRTIO_F_NOTIFY_ON_EMPTY indicates to the Guest that we will hit them with an interrupt every time the xmit queue is emptied. Because it results in lots of tx interrupts, modern Guests probably don't want it, so let's only force it when they accept the option. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> --- Documentation/lguest/lguest.c | 27

VIRTIO_F_NOTIFY_ON_EMPTY indicates to the Guest that we will hit them with an interrupt every time the xmit queue is emptied. Because it results in lots of tx interrupts, modern Guests probably don't want it, so let's only force it when they accept the option. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> --- Documentation/lguest/lguest.c | 25 +++++++++++++++++++++----

VIRTIO_F_NOTIFY_ON_EMPTY indicates to the Guest that we will hit them with an interrupt every time the xmit queue is emptied. Because it results in lots of tx interrupts, modern Guests probably don't want it, so let's only force it when they accept the option. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> --- Documentation/lguest/lguest.c | 27

VIRTIO_F_NOTIFY_ON_EMPTY indicates to the Guest that we will hit them with an interrupt every time the xmit queue is emptied. Because it results in lots of tx interrupts, modern Guests probably don't want it, so let's only force it when they accept the option. Signed-off-by: Rusty Russell <rusty at rustcorp.com.au> --- Documentation/lguest/lguest.c | 25 +++++++++++++++++++++----

virtio allows drivers to suppress callbacks (ie. interrupts) for efficiency (no locking, it's just an optimization). There's a similar mechanism for the host to suppress notifications coming from the guest: in that case, we ignore the suppression if the ring is completely full. It turns out that life is simpler if the host similarly ignores callback suppression when the ring is

virtio allows drivers to suppress callbacks (ie. interrupts) for efficiency (no locking, it's just an optimization). There's a similar mechanism for the host to suppress notifications coming from the guest: in that case, we ignore the suppression if the ring is completely full. It turns out that life is simpler if the host similarly ignores callback suppression when the ring is

This patch adds mergeable receive buffer support to qemu-kvm, to allow enabling it when vhost_net supports it. It also adds a missing call to vhost_net_ack_features() to push acked features to vhost_net. The patch is relative to Michael Tsirkin's qemu-kvm git tree. +-DLS Signed-off-by: David L Stevens <dlstevens at us.ibm.com> diff -ruNp qemu-kvm.mst/hw/vhost_net.c

This patch adds mergeable receive buffer support to qemu-kvm, to allow enabling it when vhost_net supports it. It also adds a missing call to vhost_net_ack_features() to push acked features to vhost_net. The patch is relative to Michael Tsirkin's qemu-kvm git tree. +-DLS Signed-off-by: David L Stevens <dlstevens at us.ibm.com> diff -ruNp qemu-kvm.mst/hw/vhost_net.c

The virtio_net driver is complicated by the two methods of freeing old xmit buffers (in addition to freeing old ones at the start of the xmit path). The original code used a 1/10 second timer attached to xmit_free(), reset on every xmit. Before we orphaned skbs on xmit, the transmitting userspace could block with a full socket until the timer fired, the skb destructor was called, and they were

The virtio_net driver is complicated by the two methods of freeing old xmit buffers (in addition to freeing old ones at the start of the xmit path). The original code used a 1/10 second timer attached to xmit_free(), reset on every xmit. Before we orphaned skbs on xmit, the transmitting userspace could block with a full socket until the timer fired, the skb destructor was called, and they were

Add virtio_{add,clear}_feature helper functions for manipulating a feature bits variable. This has some benefits over open coding: - add check that the bit is in a sane range - make it obvious at a glance what is going on - have a central point to change when we want to extend feature bits Convert existing code manipulating features to use the new helpers. Signed-off-by: Cornelia Huck

Add virtio_{add,clear}_feature helper functions for manipulating a feature bits variable. This has some benefits over open coding: - add check that the bit is in a sane range - make it obvious at a glance what is going on - have a central point to change when we want to extend feature bits Convert existing code manipulating features to use the new helpers. Signed-off-by: Cornelia Huck

Clang warns several times when building for 32-bit ARM along the lines of: drivers/vdpa/mlx5/net/mlx5_vnet.c:1462:31: warning: shift count >= width of type [-Wshift-count-overflow] ndev->mvdev.mlx_features |= BIT(VIRTIO_F_VERSION_1); ^~~~~~~~~~~~~~~~~~~~~~~ This is related to the BIT macro, which uses an unsigned long literal,

Clang warns several times when building for 32-bit ARM along the lines of: drivers/vdpa/mlx5/net/mlx5_vnet.c:1462:31: warning: shift count >= width of type [-Wshift-count-overflow] ndev->mvdev.mlx_features |= BIT(VIRTIO_F_VERSION_1); ^~~~~~~~~~~~~~~~~~~~~~~ This is related to the BIT macro, which uses an unsigned long literal,

Add a helper function for checking whether a bit is set in the guest features for a vdev as well as one that works on a feature bit set. Convert code that open-coded this: It cleans up the code and makes it easier to extend the guest feature bits. Signed-off-by: Cornelia Huck <cornelia.huck at de.ibm.com> --- hw/block/virtio-blk.c | 7 ++----- hw/char/virtio-serial-bus.c | 2

Add a helper function for checking whether a bit is set in the guest features for a vdev as well as one that works on a feature bit set. Convert code that open-coded this: It cleans up the code and makes it easier to extend the guest feature bits. Signed-off-by: Cornelia Huck <cornelia.huck at de.ibm.com> --- hw/block/virtio-blk.c | 7 ++----- hw/char/virtio-serial-bus.c | 2

"Michael S. Tsirkin" <mst at redhat.com> writes: > On Thu, Jul 04, 2013 at 10:49:42AM +0300, Michael S. Tsirkin wrote: >> > case). >> > >> > Regrettably, initial driver implementations used simple layouts >> > and devices came to rely on it, despite this specification >> > wording. It is thus recommended that drivers be conservative

"Michael S. Tsirkin" <mst at redhat.com> writes: > On Thu, Jul 04, 2013 at 10:49:42AM +0300, Michael S. Tsirkin wrote: >> > case). >> > >> > Regrettably, initial driver implementations used simple layouts >> > and devices came to rely on it, despite this specification >> > wording. It is thus recommended that drivers be conservative

With virtio-1, we support more than 32 feature bits. Let's make vdev->guest_features depend on the number of supported feature bits, allowing us to grow the feature bits automatically. We also need to enhance the internal functions dealing with getting and setting features with an additional index field, so that all feature bits may be accessed (in chunks of 32 bits). vhost and migration

With virtio-1, we support more than 32 feature bits. Let's make vdev->guest_features depend on the number of supported feature bits, allowing us to grow the feature bits automatically. We also need to enhance the internal functions dealing with getting and setting features with an additional index field, so that all feature bits may be accessed (in chunks of 32 bits). vhost and migration