Re: [PATCH 1/5] virtio-blk: enforce iothread-vq-mapping validation
On Mon, 05 Feb 2024 19:26, Stefan Hajnoczi wrote:
Hanna Czenczek noticed that the safety of
`vq_aio_context[vq->value] = ctx;` with user-defined vq->value inputs is
not obvious.
The code is structured in validate() + apply() steps so input validation
is there, but it happens way earlier and there is nothing that
guarantees apply() can only be called with validated inputs.
This patch moves the validate() call inside the apply() function so
validation is guaranteed. I also added the bounds checking assertion
that Hanna suggested.
Signed-off-by: Stefan Hajnoczi
---
hw/block/virtio-blk.c | 192 +++---
1 file changed, 107 insertions(+), 85 deletions(-)
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 227d83569f..e8b37fd5f4 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -1485,6 +1485,72 @@ static int virtio_blk_load_device(VirtIODevice *vdev,
QEMUFile *f,
return 0;
}
+static void virtio_resize_cb(void *opaque)
+{
+VirtIODevice *vdev = opaque;
+
+assert(qemu_get_current_aio_context() == qemu_get_aio_context());
+virtio_notify_config(vdev);
+}
+
+static void virtio_blk_resize(void *opaque)
+{
+VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
+
+/*
+ * virtio_notify_config() needs to acquire the BQL,
+ * so it can't be called from an iothread. Instead, schedule
+ * it to be run in the main context BH.
+ */
+aio_bh_schedule_oneshot(qemu_get_aio_context(), virtio_resize_cb, vdev);
+}
+
+static void virtio_blk_ioeventfd_detach(VirtIOBlock *s)
+{
+VirtIODevice *vdev = VIRTIO_DEVICE(s);
+
+for (uint16_t i = 0; i < s->conf.num_queues; i++) {
+VirtQueue *vq = virtio_get_queue(vdev, i);
+virtio_queue_aio_detach_host_notifier(vq, s->vq_aio_context[i]);
+}
+}
+
+static void virtio_blk_ioeventfd_attach(VirtIOBlock *s)
+{
+VirtIODevice *vdev = VIRTIO_DEVICE(s);
+
+for (uint16_t i = 0; i < s->conf.num_queues; i++) {
+VirtQueue *vq = virtio_get_queue(vdev, i);
+virtio_queue_aio_attach_host_notifier(vq, s->vq_aio_context[i]);
+}
+}
+
+/* Suspend virtqueue ioeventfd processing during drain */
+static void virtio_blk_drained_begin(void *opaque)
+{
+VirtIOBlock *s = opaque;
+
+if (s->ioeventfd_started) {
+virtio_blk_ioeventfd_detach(s);
+}
+}
+
+/* Resume virtqueue ioeventfd processing after drain */
+static void virtio_blk_drained_end(void *opaque)
+{
+VirtIOBlock *s = opaque;
+
+if (s->ioeventfd_started) {
+virtio_blk_ioeventfd_attach(s);
+}
+}
+
+static const BlockDevOps virtio_block_ops = {
+.resize_cb = virtio_blk_resize,
+.drained_begin = virtio_blk_drained_begin,
+.drained_end = virtio_blk_drained_end,
+};
+
static bool
validate_iothread_vq_mapping_list(IOThreadVirtQueueMappingList *list,
uint16_t num_queues, Error **errp)
@@ -1547,81 +1613,33 @@
validate_iothread_vq_mapping_list(IOThreadVirtQueueMappingList *list,
return true;
}
-static void virtio_resize_cb(void *opaque)
-{
-VirtIODevice *vdev = opaque;
-
-assert(qemu_get_current_aio_context() == qemu_get_aio_context());
-virtio_notify_config(vdev);
-}
-
-static void virtio_blk_resize(void *opaque)
-{
-VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
-
-/*
- * virtio_notify_config() needs to acquire the BQL,
- * so it can't be called from an iothread. Instead, schedule
- * it to be run in the main context BH.
- */
-aio_bh_schedule_oneshot(qemu_get_aio_context(), virtio_resize_cb, vdev);
-}
-
-static void virtio_blk_ioeventfd_detach(VirtIOBlock *s)
-{
-VirtIODevice *vdev = VIRTIO_DEVICE(s);
-
-for (uint16_t i = 0; i < s->conf.num_queues; i++) {
-VirtQueue *vq = virtio_get_queue(vdev, i);
-virtio_queue_aio_detach_host_notifier(vq, s->vq_aio_context[i]);
-}
-}
-
-static void virtio_blk_ioeventfd_attach(VirtIOBlock *s)
-{
-VirtIODevice *vdev = VIRTIO_DEVICE(s);
-
-for (uint16_t i = 0; i < s->conf.num_queues; i++) {
-VirtQueue *vq = virtio_get_queue(vdev, i);
-virtio_queue_aio_attach_host_notifier(vq, s->vq_aio_context[i]);
-}
-}
-
-/* Suspend virtqueue ioeventfd processing during drain */
-static void virtio_blk_drained_begin(void *opaque)
-{
-VirtIOBlock *s = opaque;
-
-if (s->ioeventfd_started) {
-virtio_blk_ioeventfd_detach(s);
-}
-}
-
-/* Resume virtqueue ioeventfd processing after drain */
-static void virtio_blk_drained_end(void *opaque)
-{
-VirtIOBlock *s = opaque;
-
-if (s->ioeventfd_started) {
-virtio_blk_ioeventfd_attach(s);
-}
-}
-
-static const BlockDevOps virtio_block_ops = {
-.resize_cb = virtio_blk_resize,
-.drained_begin = virtio_blk_drained_begin,
-.drained_end = virtio_blk_drained_end,
-};
-
-/* Generate vq:AioContext mappings from a validated iothread-vq-mapping list */
-static void
-apply_vq_mapping(IOThreadVirtQueueMappingList *iothread_vq_mapping_list,
-
Re: [PATCH 1/5] virtio-blk: enforce iothread-vq-mapping validation
On 05.02.24 18:26, Stefan Hajnoczi wrote:
Hanna Czenczek noticed that the safety of
`vq_aio_context[vq->value] = ctx;` with user-defined vq->value inputs is
not obvious.
The code is structured in validate() + apply() steps so input validation
is there, but it happens way earlier and there is nothing that
guarantees apply() can only be called with validated inputs.
This patch moves the validate() call inside the apply() function so
validation is guaranteed. I also added the bounds checking assertion
that Hanna suggested.
Signed-off-by: Stefan Hajnoczi
---
hw/block/virtio-blk.c | 192 +++---
1 file changed, 107 insertions(+), 85 deletions(-)
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 227d83569f..e8b37fd5f4 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
[...]
@@ -1660,6 +1681,14 @@ static bool virtio_blk_vq_aio_context_init(VirtIOBlock
*s, Error **errp)
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+if (conf->iothread && conf->iothread_vq_mapping_list) {
+if (conf->iothread) {
This inner condition should probably be dropped. With that done:
Reviewed-by: Hanna Czenczek
+error_setg(errp, "iothread and iothread-vq-mapping properties "
+ "cannot be set at the same time");
+return false;
+}
+}
+
if (conf->iothread || conf->iothread_vq_mapping_list) {
if (!k->set_guest_notifiers || !k->ioeventfd_assign) {
error_setg(errp,
Re: [PATCH 1/5] virtio-blk: enforce iothread-vq-mapping validation
On Tue, Feb 06, 2024 at 09:29:29AM +0200, Manos Pitsidianakis wrote:
> On Mon, 05 Feb 2024 19:26, Stefan Hajnoczi wrote:
> > Hanna Czenczek noticed that the safety of
> > `vq_aio_context[vq->value] = ctx;` with user-defined vq->value inputs is
> > not obvious.
> >
> > The code is structured in validate() + apply() steps so input validation
> > is there, but it happens way earlier and there is nothing that
> > guarantees apply() can only be called with validated inputs.
> >
> > This patch moves the validate() call inside the apply() function so
> > validation is guaranteed. I also added the bounds checking assertion
> > that Hanna suggested.
> >
> > Signed-off-by: Stefan Hajnoczi
> > ---
> > hw/block/virtio-blk.c | 192 +++---
> > 1 file changed, 107 insertions(+), 85 deletions(-)
> >
> > diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> > index 227d83569f..e8b37fd5f4 100644
> > --- a/hw/block/virtio-blk.c
> > +++ b/hw/block/virtio-blk.c
> > @@ -1485,6 +1485,72 @@ static int virtio_blk_load_device(VirtIODevice
> > *vdev, QEMUFile *f,
> > return 0;
> > }
> >
> > +static void virtio_resize_cb(void *opaque)
> > +{
> > +VirtIODevice *vdev = opaque;
> > +
> > +assert(qemu_get_current_aio_context() == qemu_get_aio_context());
> > +virtio_notify_config(vdev);
> > +}
> > +
> > +static void virtio_blk_resize(void *opaque)
> > +{
> > +VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
> > +
> > +/*
> > + * virtio_notify_config() needs to acquire the BQL,
> > + * so it can't be called from an iothread. Instead, schedule
> > + * it to be run in the main context BH.
> > + */
> > +aio_bh_schedule_oneshot(qemu_get_aio_context(), virtio_resize_cb,
> > vdev);
> > +}
> > +
> > +static void virtio_blk_ioeventfd_detach(VirtIOBlock *s)
> > +{
> > +VirtIODevice *vdev = VIRTIO_DEVICE(s);
> > +
> > +for (uint16_t i = 0; i < s->conf.num_queues; i++) {
> > +VirtQueue *vq = virtio_get_queue(vdev, i);
> > +virtio_queue_aio_detach_host_notifier(vq, s->vq_aio_context[i]);
> > +}
> > +}
> > +
> > +static void virtio_blk_ioeventfd_attach(VirtIOBlock *s)
> > +{
> > +VirtIODevice *vdev = VIRTIO_DEVICE(s);
> > +
> > +for (uint16_t i = 0; i < s->conf.num_queues; i++) {
> > +VirtQueue *vq = virtio_get_queue(vdev, i);
> > +virtio_queue_aio_attach_host_notifier(vq, s->vq_aio_context[i]);
> > +}
> > +}
> > +
> > +/* Suspend virtqueue ioeventfd processing during drain */
> > +static void virtio_blk_drained_begin(void *opaque)
> > +{
> > +VirtIOBlock *s = opaque;
> > +
> > +if (s->ioeventfd_started) {
> > +virtio_blk_ioeventfd_detach(s);
> > +}
> > +}
> > +
> > +/* Resume virtqueue ioeventfd processing after drain */
> > +static void virtio_blk_drained_end(void *opaque)
> > +{
> > +VirtIOBlock *s = opaque;
> > +
> > +if (s->ioeventfd_started) {
> > +virtio_blk_ioeventfd_attach(s);
> > +}
> > +}
> > +
> > +static const BlockDevOps virtio_block_ops = {
> > +.resize_cb = virtio_blk_resize,
> > +.drained_begin = virtio_blk_drained_begin,
> > +.drained_end = virtio_blk_drained_end,
> > +};
> > +
> > static bool
> > validate_iothread_vq_mapping_list(IOThreadVirtQueueMappingList *list,
> > uint16_t num_queues, Error **errp)
> > @@ -1547,81 +1613,33 @@
> > validate_iothread_vq_mapping_list(IOThreadVirtQueueMappingList *list,
> > return true;
> > }
> >
> > -static void virtio_resize_cb(void *opaque)
> > -{
> > -VirtIODevice *vdev = opaque;
> > -
> > -assert(qemu_get_current_aio_context() == qemu_get_aio_context());
> > -virtio_notify_config(vdev);
> > -}
> > -
> > -static void virtio_blk_resize(void *opaque)
> > -{
> > -VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
> > -
> > -/*
> > - * virtio_notify_config() needs to acquire the BQL,
> > - * so it can't be called from an iothread. Instead, schedule
> > - * it to be run in the main context BH.
> > - */
> > -aio_bh_schedule_oneshot(qemu_get_aio_context(), virtio_resize_cb,
> > vdev);
> > -}
> > -
> > -static void virtio_blk_ioeventfd_detach(VirtIOBlock *s)
> > -{
> > -VirtIODevice *vdev = VIRTIO_DEVICE(s);
> > -
> > -for (uint16_t i = 0; i < s->conf.num_queues; i++) {
> > -VirtQueue *vq = virtio_get_queue(vdev, i);
> > -virtio_queue_aio_detach_host_notifier(vq, s->vq_aio_context[i]);
> > -}
> > -}
> > -
> > -static void virtio_blk_ioeventfd_attach(VirtIOBlock *s)
> > -{
> > -VirtIODevice *vdev = VIRTIO_DEVICE(s);
> > -
> > -for (uint16_t i = 0; i < s->conf.num_queues; i++) {
> > -VirtQueue *vq = virtio_get_queue(vdev, i);
> > -virtio_queue_aio_attach_host_notifier(vq, s->vq_aio_context[i]);
> > -}
> > -}
> > -
> > -/* Suspend virtqueue ioeventfd processing during drain */
> > -static void virtio_blk_drained_begin(void *opaque)
> > -{
> > -VirtIOBlock *s = opaque;
> > -
> > -if (s->ioeventfd
