search for: vring_get_buf

...000ed404 vr->num: 128 virtio_scsi_cmd, after vring_kick vr: 0x000ed404 vr->num: 128 virtio_scsi_cmd, after vring_more_used #4 vr: 0x000ed404 vr->num: 1 ^^^^^^^^^^^^^^^^^^^^^^^^^ Reset from 128 to 1 immediate after first vring_more_used()..? vring_get_buf last_used_idx: 0 vr: 0x000ed404 vr->num: 1 vring_get_buf checking &used->ring[0] vring_get_buf, using new last_unsed: 0 >>>>>>>>>>>>>>>>>> vring_get_buf using id: 0 from elem->id: 0x000ed004 vring_detach: vq->free_head: 3 vring_d...

...000ed404 vr->num: 128 virtio_scsi_cmd, after vring_kick vr: 0x000ed404 vr->num: 128 virtio_scsi_cmd, after vring_more_used #4 vr: 0x000ed404 vr->num: 1 ^^^^^^^^^^^^^^^^^^^^^^^^^ Reset from 128 to 1 immediate after first vring_more_used()..? vring_get_buf last_used_idx: 0 vr: 0x000ed404 vr->num: 1 vring_get_buf checking &used->ring[0] vring_get_buf, using new last_unsed: 0 >>>>>>>>>>>>>>>>>> vring_get_buf using id: 0 from elem->id: 0x000ed004 vring_detach: vq->free_head: 3 vring_d...

kvm (and lguest!) want to get more speed out of the tun device. We already have an ABI for guest<->host comms, called virtio_ring; extending tun to understand this (with its async nature and batching) make for an efficient network. But moreover: the same things that make virtio a good guest<->host transport make it appealing as a userspace<->kernel transport. So rather

kvm (and lguest!) want to get more speed out of the tun device. We already have an ABI for guest<->host comms, called virtio_ring; extending tun to understand this (with its async nature and batching) make for an efficient network. But moreover: the same things that make virtio a good guest<->host transport make it appealing as a userspace<->kernel transport. So rather

...--- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -260,6 +260,8 @@ irqreturn_t vring_interrupt(int irq, void *_vq) return IRQ_HANDLED; } +EXPORT_SYMBOL_GPL(vring_interrupt); + static struct virtqueue_ops vring_vq_ops = { .add_buf = vring_add_buf, .get_buf = vring_get_buf, @@ -312,8 +314,12 @@ struct virtqueue *vring_new_virtqueue(unsigned int num, return &vq->vq; } +EXPORT_SYMBOL_GPL(vring_new_virtqueue); + void vring_del_virtqueue(struct virtqueue *vq) { kfree(to_vvq(vq)); } +EXPORT_SYMBOL_GPL(vring_del_virtqueue); + -- 1.5.3.3

This patch series implements a PCI driver for virtio. This allows virtio devices (like block and network) to be used in QEMU/KVM. I'll post a very early KVM userspace backend in kvm-devel for those that are interested. This series depends on the two virtio fixes I've posted and Rusty's config_ops refactoring. I've tested with these patches on Rusty's experimental virtio

...->idx += vq->num_added; vq->num_added = 0; /* Need to update avail index before checking if we should notify */ - mb(); + smp_mb(); if (!(vq->vring.used->flags & VRING_USED_F_NO_NOTIFY)) /* Prod other side to tell it about changes. */ @@ -286,7 +286,7 @@ static void *vring_get_buf(struct virtqueue *_vq, unsigned int *len) } /* Only get used array entries after they have been exposed by host. */ - rmb(); + smp_rmb(); i = vq->vring.used->ring[vq->last_used_idx%vq->vring.num].id; *len = vq->vring.used->ring[vq->last_used_idx%vq->vring.num].le...

This patch series implements a PCI driver for virtio. This allows virtio devices (like block and network) to be used in QEMU/KVM. I'll post a very early KVM userspace backend in kvm-devel for those that are interested. This series depends on the two virtio fixes I've posted and Rusty's config_ops refactoring. I've tested with these patches on Rusty's experimental virtio

...--- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -260,6 +260,8 @@ irqreturn_t vring_interrupt(int irq, void *_vq) return IRQ_HANDLED; } +EXPORT_SYMBOL_GPL(vring_interrupt); + static struct virtqueue_ops vring_vq_ops = { .add_buf = vring_add_buf, .get_buf = vring_get_buf, @@ -312,8 +314,12 @@ struct virtqueue *vring_new_virtqueue(unsigned int num, return &vq->vq; } +EXPORT_SYMBOL_GPL(vring_new_virtqueue); + void vring_del_virtqueue(struct virtqueue *vq) { kfree(to_vvq(vq)); } +EXPORT_SYMBOL_GPL(vring_del_virtqueue); + -- 1.5.3.3

...->idx += vq->num_added; vq->num_added = 0; /* Need to update avail index before checking if we should notify */ - mb(); + smp_mb(); if (!(vq->vring.used->flags & VRING_USED_F_NO_NOTIFY)) /* Prod other side to tell it about changes. */ @@ -286,7 +286,7 @@ static void *vring_get_buf(struct virtqueue *_vq, unsigned int *len) } /* Only get used array entries after they have been exposed by host. */ - rmb(); + smp_rmb(); i = vq->vring.used->ring[vq->last_used_idx%vq->vring.num].id; *len = vq->vring.used->ring[vq->last_used_idx%vq->vring.num].le...

...(_vq); + + return vq->num_free ? true : false; +} + static int vring_add_buf(struct virtqueue *_vq, struct scatterlist sg[], unsigned int out, @@ -350,6 +357,7 @@ EXPORT_SYMBOL_GPL(vring_interrupt); static struct virtqueue_ops vring_vq_ops = { .add_buf = vring_add_buf, .get_buf = vring_get_buf, + .can_add_buf = vring_can_add_buf, .kick = vring_kick, .disable_cb = vring_disable_cb, .enable_cb = vring_enable_cb, diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 4fca4f5..cc0e3aa 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -35,6 +35,9 @@ struct...

...(_vq); + + return vq->num_free ? true : false; +} + static int vring_add_buf(struct virtqueue *_vq, struct scatterlist sg[], unsigned int out, @@ -350,6 +357,7 @@ EXPORT_SYMBOL_GPL(vring_interrupt); static struct virtqueue_ops vring_vq_ops = { .add_buf = vring_add_buf, .get_buf = vring_get_buf, + .can_add_buf = vring_can_add_buf, .kick = vring_kick, .disable_cb = vring_disable_cb, .enable_cb = vring_enable_cb, diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 4fca4f5..cc0e3aa 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -35,6 +35,9 @@ struct...

...t;idx += vq->num_added; vq->num_added = 0; /* Need to update avail index before checking if we should notify */ - mb(); + virtio_mb(); if (!(vq->vring.used->flags & VRING_USED_F_NO_NOTIFY)) /* Prod other side to tell it about changes. */ @@ -286,7 +304,7 @@ static void *vring_get_buf(struct virtqueue *_vq, unsigned int *len) } /* Only get used array entries after they have been exposed by host. */ - rmb(); + virtio_rmb(); i = vq->vring.used->ring[vq->last_used_idx%vq->vring.num].id; *len = vq->vring.used->ring[vq->last_used_idx%vq->vring.num]...

...t;idx += vq->num_added; vq->num_added = 0; /* Need to update avail index before checking if we should notify */ - mb(); + virtio_mb(); if (!(vq->vring.used->flags & VRING_USED_F_NO_NOTIFY)) /* Prod other side to tell it about changes. */ @@ -286,7 +304,7 @@ static void *vring_get_buf(struct virtqueue *_vq, unsigned int *len) } /* Only get used array entries after they have been exposed by host. */ - rmb(); + virtio_rmb(); i = vq->vring.used->ring[vq->last_used_idx%vq->vring.num].id; *len = vq->vring.used->ring[vq->last_used_idx%vq->vring.num]...

virtqueue ops were introduced in the hope that we'll have multiple implementations besides virtio_ring, but none have surfaced so far, and given that existing virtio ring is deployed in production we are likely stuck with it now, so this layer just adds complexity and overhead. Further, the need to pass vq twice to each call (as in dev->vq->vq_ops->kick(dev->vq) ) adds potential

virtqueue ops were introduced in the hope that we'll have multiple implementations besides virtio_ring, but none have surfaced so far, and given that existing virtio ring is deployed in production we are likely stuck with it now, so this layer just adds complexity and overhead. Further, the need to pass vq twice to each call (as in dev->vq->vq_ops->kick(dev->vq) ) adds potential

Rusty, Anthony, Dor, I need your brain power :-) On smp guests I have seen a problem with virtio (the version in curent Avi's git) which do not occur on single processor guests: kernel BUG at /space/kvm/drivers/virtio/virtio_ring.c:228! illegal operation: 0001 [#1] Modules linked in: ipv6 CPU: 2 Not tainted Process swapper (pid: 0, task: 000000000f83e038, ksp: 000000000f877d70) Krnl

Rusty, Anthony, Dor, I need your brain power :-) On smp guests I have seen a problem with virtio (the version in curent Avi's git) which do not occur on single processor guests: kernel BUG at /space/kvm/drivers/virtio/virtio_ring.c:228! illegal operation: 0001 [#1] Modules linked in: ipv6 CPU: 2 Not tainted Process swapper (pid: 0, task: 000000000f83e038, ksp: 000000000f877d70) Krnl

...to_vvq(_vq); + + return vq->num_free ? 1 : 0; +} + static int vring_add_buf(struct virtqueue *_vq, struct scatterlist sg[], unsigned int out, @@ -350,6 +357,7 @@ EXPORT_SYMBOL_GPL(vring_interrupt); static struct virtqueue_ops vring_vq_ops = { .add_buf = vring_add_buf, .get_buf = vring_get_buf, + .can_add_buf = vring_can_add_buf, .kick = vring_kick, .disable_cb = vring_disable_cb, .enable_cb = vring_enable_cb, diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 4fca4f5..cc0e3aa 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -35,6 +35,9 @@ struct...

...to_vvq(_vq); + + return vq->num_free ? 1 : 0; +} + static int vring_add_buf(struct virtqueue *_vq, struct scatterlist sg[], unsigned int out, @@ -350,6 +357,7 @@ EXPORT_SYMBOL_GPL(vring_interrupt); static struct virtqueue_ops vring_vq_ops = { .add_buf = vring_add_buf, .get_buf = vring_get_buf, + .can_add_buf = vring_can_add_buf, .kick = vring_kick, .disable_cb = vring_disable_cb, .enable_cb = vring_enable_cb, diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 4fca4f5..cc0e3aa 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -35,6 +35,9 @@ struct...