Michael S. Tsirkin
2022-Jan-20 10:55 UTC
[PATCH v2 07/12] virtio: queue_reset: pci: support VIRTIO_F_RING_RESET
On Thu, Jan 20, 2022 at 02:42:58PM +0800, Xuan Zhuo wrote:> This patch implements virtio pci support for QUEUE RESET. > > Performing reset on a queue is divided into two steps: > > 1. reset_vq: reset one vq > 2. enable_reset_vq: re-enable the reset queue > > In the first step, these tasks will be completed: > 1. notify the hardware queue to reset > 2. recycle the buffer from vq > 3. delete the vq > > When deleting a vq, vp_del_vq() will be called to release all the memory > of the vq. But this does not affect the process of deleting vqs, because > that is based on the queue to release all the vqs. During this process, > the vq has been removed from the queue. > > When deleting vq, info and vq will be released, and I save msix_vec in > vp_dev->vqs[queue_index]. When re-enable, the current msix_vec can be > reused. And based on intx_enabled to determine which method to use to > enable this queue. > > Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>There's something I don't understand here. It looks like you assume that when you reset a queue, you also reset the mapping from queue to event vector. The spec does not say it should, and I don't think it's useful to extend spec to do it - we already have a simple way to tweak the mapping. Avoid doing that, and things will be much easier, with no need to interact with a transport, won't they?> --- > drivers/virtio/virtio_pci_common.c | 49 ++++++++++++++++++++ > drivers/virtio/virtio_pci_common.h | 4 ++ > drivers/virtio/virtio_pci_modern.c | 73 ++++++++++++++++++++++++++++++ > 3 files changed, 126 insertions(+) > > diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c > index 5afe207ce28a..28b5ffde4621 100644 > --- a/drivers/virtio/virtio_pci_common.c > +++ b/drivers/virtio/virtio_pci_common.c > @@ -464,6 +464,55 @@ int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs, > return vp_find_vqs_intx(vdev, nvqs, vqs, callbacks, names, ctx); > } > > +#define VQ_IS_DELETED(vp_dev, idx) ((unsigned long)vp_dev->vqs[idx] & 1) > +#define VQ_RESET_MSIX_VEC(vp_dev, idx) ((unsigned long)vp_dev->vqs[idx] >> 2) > +#define VQ_RESET_MARK(msix_vec) ((void *)(long)((msix_vec << 2) + 1)) > + > +void vp_del_reset_vq(struct virtio_device *vdev, u16 queue_index) > +{ > + struct virtio_pci_device *vp_dev = to_vp_device(vdev); > + struct virtio_pci_vq_info *info; > + u16 msix_vec; > + > + info = vp_dev->vqs[queue_index]; > + > + msix_vec = info->msix_vector; > + > + /* delete vq */ > + vp_del_vq(info->vq); > + > + /* Mark the vq has been deleted, and save the msix_vec. */ > + vp_dev->vqs[queue_index] = VQ_RESET_MARK(msix_vec); > +} > + > +struct virtqueue *vp_enable_reset_vq(struct virtio_device *vdev, > + int queue_index, > + vq_callback_t *callback, > + const char *name, > + const bool ctx) > +{ > + struct virtio_pci_device *vp_dev = to_vp_device(vdev); > + struct virtqueue *vq; > + u16 msix_vec; > + > + if (!VQ_IS_DELETED(vp_dev, queue_index)) > + return ERR_PTR(-EPERM); > + > + msix_vec = VQ_RESET_MSIX_VEC(vp_dev, queue_index); > + > + if (vp_dev->intx_enabled) > + vq = vp_setup_vq(vdev, queue_index, callback, name, ctx, > + VIRTIO_MSI_NO_VECTOR); > + else > + vq = vp_enable_vq_msix(vdev, queue_index, callback, name, ctx, > + msix_vec); > + > + if (IS_ERR(vq)) > + vp_dev->vqs[queue_index] = VQ_RESET_MARK(msix_vec); > + > + return vq; > +} > + > const char *vp_bus_name(struct virtio_device *vdev) > { > struct virtio_pci_device *vp_dev = to_vp_device(vdev); > diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h > index 23f6c5c678d5..96c13b1398f8 100644 > --- a/drivers/virtio/virtio_pci_common.h > +++ b/drivers/virtio/virtio_pci_common.h > @@ -115,6 +115,10 @@ int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs, > struct virtqueue *vqs[], vq_callback_t *callbacks[], > const char * const names[], const bool *ctx, > struct irq_affinity *desc); > +void vp_del_reset_vq(struct virtio_device *vdev, u16 queue_index); > +struct virtqueue *vp_enable_reset_vq(struct virtio_device *vdev, int queue_index, > + vq_callback_t *callback, const char *name, > + const bool ctx); > const char *vp_bus_name(struct virtio_device *vdev); > > /* Setup the affinity for a virtqueue: > diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c > index 5455bc041fb6..fbf87239c920 100644 > --- a/drivers/virtio/virtio_pci_modern.c > +++ b/drivers/virtio/virtio_pci_modern.c > @@ -34,6 +34,9 @@ static void vp_transport_features(struct virtio_device *vdev, u64 features) > if ((features & BIT_ULL(VIRTIO_F_SR_IOV)) && > pci_find_ext_capability(pci_dev, PCI_EXT_CAP_ID_SRIOV)) > __virtio_set_bit(vdev, VIRTIO_F_SR_IOV); > + > + if (features & BIT_ULL(VIRTIO_F_RING_RESET)) > + __virtio_set_bit(vdev, VIRTIO_F_RING_RESET); > } > > /* virtio config->finalize_features() implementation */ > @@ -176,6 +179,72 @@ static void vp_reset(struct virtio_device *vdev) > vp_disable_cbs(vdev); > } > > +static int vp_modern_reset_vq(struct virtio_device *vdev, u16 queue_index, > + vq_reset_callback_t *callback, void *data) > +{ > + struct virtio_pci_device *vp_dev = to_vp_device(vdev); > + struct virtio_pci_modern_device *mdev = &vp_dev->mdev; > + struct virtio_pci_vq_info *info; > + u16 msix_vec; > + void *buf; > + > + if (!virtio_has_feature(vdev, VIRTIO_F_RING_RESET)) > + return -ENOENT; > + > + vp_modern_set_queue_reset(mdev, queue_index); > + > + /* After write 1 to queue reset, the driver MUST wait for a read of > + * queue reset to return 1. > + */ > + while (vp_modern_get_queue_reset(mdev, queue_index) != 1) > + msleep(1); > + > + info = vp_dev->vqs[queue_index]; > + msix_vec = info->msix_vector; > + > + /* Disable VQ callback. */ > + if (vp_dev->per_vq_vectors && msix_vec != VIRTIO_MSI_NO_VECTOR) > + disable_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec)); > + > + while ((buf = virtqueue_detach_unused_buf(info->vq)) != NULL) > + callback(vdev, buf, data); > + > + vp_del_reset_vq(vdev, queue_index); > + > + return 0; > +} > + > +static struct virtqueue *vp_modern_enable_reset_vq(struct virtio_device *vdev, > + u16 queue_index, > + vq_callback_t *callback, > + const char *name, > + const bool *ctx) > +{ > + struct virtio_pci_device *vp_dev = to_vp_device(vdev); > + struct virtio_pci_modern_device *mdev = &vp_dev->mdev; > + struct virtqueue *vq; > + u16 msix_vec; > + > + if (!virtio_has_feature(vdev, VIRTIO_F_RING_RESET)) > + return ERR_PTR(-ENOENT); > + > + /* check queue reset status */ > + if (vp_modern_get_queue_reset(mdev, queue_index) != 1) > + return ERR_PTR(-EBUSY); > + > + vq = vp_enable_reset_vq(vdev, queue_index, callback, name, ctx); > + if (IS_ERR(vq)) > + return vq; > + > + vp_modern_set_queue_enable(&vp_dev->mdev, vq->index, true); > + > + msix_vec = vp_dev->vqs[queue_index]->msix_vector; > + if (vp_dev->per_vq_vectors && msix_vec != VIRTIO_MSI_NO_VECTOR) > + enable_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec)); > + > + return vq; > +} > + > static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector) > { > return vp_modern_config_vector(&vp_dev->mdev, vector); > @@ -395,6 +464,8 @@ static const struct virtio_config_ops virtio_pci_config_nodev_ops = { > .set_vq_affinity = vp_set_vq_affinity, > .get_vq_affinity = vp_get_vq_affinity, > .get_shm_region = vp_get_shm_region, > + .reset_vq = vp_modern_reset_vq, > + .enable_reset_vq = vp_modern_enable_reset_vq, > }; > > static const struct virtio_config_ops virtio_pci_config_ops = { > @@ -413,6 +484,8 @@ static const struct virtio_config_ops virtio_pci_config_ops = { > .set_vq_affinity = vp_set_vq_affinity, > .get_vq_affinity = vp_get_vq_affinity, > .get_shm_region = vp_get_shm_region, > + .reset_vq = vp_modern_reset_vq, > + .enable_reset_vq = vp_modern_enable_reset_vq, > }; > > /* the PCI probing function */ > -- > 2.31.0
Xuan Zhuo
2022-Jan-20 11:46 UTC
[PATCH v2 07/12] virtio: queue_reset: pci: support VIRTIO_F_RING_RESET
On Thu, 20 Jan 2022 05:55:14 -0500, Michael S. Tsirkin <mst at redhat.com> wrote:> On Thu, Jan 20, 2022 at 02:42:58PM +0800, Xuan Zhuo wrote: > > This patch implements virtio pci support for QUEUE RESET. > > > > Performing reset on a queue is divided into two steps: > > > > 1. reset_vq: reset one vq > > 2. enable_reset_vq: re-enable the reset queue > > > > In the first step, these tasks will be completed: > > 1. notify the hardware queue to reset > > 2. recycle the buffer from vq > > 3. delete the vq > > > > When deleting a vq, vp_del_vq() will be called to release all the memory > > of the vq. But this does not affect the process of deleting vqs, because > > that is based on the queue to release all the vqs. During this process, > > the vq has been removed from the queue. > > > > When deleting vq, info and vq will be released, and I save msix_vec in > > vp_dev->vqs[queue_index]. When re-enable, the current msix_vec can be > > reused. And based on intx_enabled to determine which method to use to > > enable this queue. > > > > Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com> > > There's something I don't understand here. It looks like > you assume that when you reset a queue, you also > reset the mapping from queue to event vector. > The spec does not say it should, and I don't think it's > useful to extend spec to do it - we already have a simple > way to tweak the mapping. >Sorry, what is the already existing method you are referring to, I didn't find it. I think you mean that we don't have to reset the event vector, I think you are right. Thanks.> Avoid doing that, and things will be much easier, with no need > to interact with a transport, won't they? > > > > --- > > drivers/virtio/virtio_pci_common.c | 49 ++++++++++++++++++++ > > drivers/virtio/virtio_pci_common.h | 4 ++ > > drivers/virtio/virtio_pci_modern.c | 73 ++++++++++++++++++++++++++++++ > > 3 files changed, 126 insertions(+) > > > > diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c > > index 5afe207ce28a..28b5ffde4621 100644 > > --- a/drivers/virtio/virtio_pci_common.c > > +++ b/drivers/virtio/virtio_pci_common.c > > @@ -464,6 +464,55 @@ int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs, > > return vp_find_vqs_intx(vdev, nvqs, vqs, callbacks, names, ctx); > > } > > > > +#define VQ_IS_DELETED(vp_dev, idx) ((unsigned long)vp_dev->vqs[idx] & 1) > > +#define VQ_RESET_MSIX_VEC(vp_dev, idx) ((unsigned long)vp_dev->vqs[idx] >> 2) > > +#define VQ_RESET_MARK(msix_vec) ((void *)(long)((msix_vec << 2) + 1)) > > + > > +void vp_del_reset_vq(struct virtio_device *vdev, u16 queue_index) > > +{ > > + struct virtio_pci_device *vp_dev = to_vp_device(vdev); > > + struct virtio_pci_vq_info *info; > > + u16 msix_vec; > > + > > + info = vp_dev->vqs[queue_index]; > > + > > + msix_vec = info->msix_vector; > > + > > + /* delete vq */ > > + vp_del_vq(info->vq); > > + > > + /* Mark the vq has been deleted, and save the msix_vec. */ > > + vp_dev->vqs[queue_index] = VQ_RESET_MARK(msix_vec); > > +} > > + > > +struct virtqueue *vp_enable_reset_vq(struct virtio_device *vdev, > > + int queue_index, > > + vq_callback_t *callback, > > + const char *name, > > + const bool ctx) > > +{ > > + struct virtio_pci_device *vp_dev = to_vp_device(vdev); > > + struct virtqueue *vq; > > + u16 msix_vec; > > + > > + if (!VQ_IS_DELETED(vp_dev, queue_index)) > > + return ERR_PTR(-EPERM); > > + > > + msix_vec = VQ_RESET_MSIX_VEC(vp_dev, queue_index); > > + > > + if (vp_dev->intx_enabled) > > + vq = vp_setup_vq(vdev, queue_index, callback, name, ctx, > > + VIRTIO_MSI_NO_VECTOR); > > + else > > + vq = vp_enable_vq_msix(vdev, queue_index, callback, name, ctx, > > + msix_vec); > > + > > + if (IS_ERR(vq)) > > + vp_dev->vqs[queue_index] = VQ_RESET_MARK(msix_vec); > > + > > + return vq; > > +} > > + > > const char *vp_bus_name(struct virtio_device *vdev) > > { > > struct virtio_pci_device *vp_dev = to_vp_device(vdev); > > diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h > > index 23f6c5c678d5..96c13b1398f8 100644 > > --- a/drivers/virtio/virtio_pci_common.h > > +++ b/drivers/virtio/virtio_pci_common.h > > @@ -115,6 +115,10 @@ int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs, > > struct virtqueue *vqs[], vq_callback_t *callbacks[], > > const char * const names[], const bool *ctx, > > struct irq_affinity *desc); > > +void vp_del_reset_vq(struct virtio_device *vdev, u16 queue_index); > > +struct virtqueue *vp_enable_reset_vq(struct virtio_device *vdev, int queue_index, > > + vq_callback_t *callback, const char *name, > > + const bool ctx); > > const char *vp_bus_name(struct virtio_device *vdev); > > > > /* Setup the affinity for a virtqueue: > > diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c > > index 5455bc041fb6..fbf87239c920 100644 > > --- a/drivers/virtio/virtio_pci_modern.c > > +++ b/drivers/virtio/virtio_pci_modern.c > > @@ -34,6 +34,9 @@ static void vp_transport_features(struct virtio_device *vdev, u64 features) > > if ((features & BIT_ULL(VIRTIO_F_SR_IOV)) && > > pci_find_ext_capability(pci_dev, PCI_EXT_CAP_ID_SRIOV)) > > __virtio_set_bit(vdev, VIRTIO_F_SR_IOV); > > + > > + if (features & BIT_ULL(VIRTIO_F_RING_RESET)) > > + __virtio_set_bit(vdev, VIRTIO_F_RING_RESET); > > } > > > > /* virtio config->finalize_features() implementation */ > > @@ -176,6 +179,72 @@ static void vp_reset(struct virtio_device *vdev) > > vp_disable_cbs(vdev); > > } > > > > +static int vp_modern_reset_vq(struct virtio_device *vdev, u16 queue_index, > > + vq_reset_callback_t *callback, void *data) > > +{ > > + struct virtio_pci_device *vp_dev = to_vp_device(vdev); > > + struct virtio_pci_modern_device *mdev = &vp_dev->mdev; > > + struct virtio_pci_vq_info *info; > > + u16 msix_vec; > > + void *buf; > > + > > + if (!virtio_has_feature(vdev, VIRTIO_F_RING_RESET)) > > + return -ENOENT; > > + > > + vp_modern_set_queue_reset(mdev, queue_index); > > + > > + /* After write 1 to queue reset, the driver MUST wait for a read of > > + * queue reset to return 1. > > + */ > > + while (vp_modern_get_queue_reset(mdev, queue_index) != 1) > > + msleep(1); > > + > > + info = vp_dev->vqs[queue_index]; > > + msix_vec = info->msix_vector; > > + > > + /* Disable VQ callback. */ > > + if (vp_dev->per_vq_vectors && msix_vec != VIRTIO_MSI_NO_VECTOR) > > + disable_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec)); > > + > > + while ((buf = virtqueue_detach_unused_buf(info->vq)) != NULL) > > + callback(vdev, buf, data); > > + > > + vp_del_reset_vq(vdev, queue_index); > > + > > + return 0; > > +} > > + > > +static struct virtqueue *vp_modern_enable_reset_vq(struct virtio_device *vdev, > > + u16 queue_index, > > + vq_callback_t *callback, > > + const char *name, > > + const bool *ctx) > > +{ > > + struct virtio_pci_device *vp_dev = to_vp_device(vdev); > > + struct virtio_pci_modern_device *mdev = &vp_dev->mdev; > > + struct virtqueue *vq; > > + u16 msix_vec; > > + > > + if (!virtio_has_feature(vdev, VIRTIO_F_RING_RESET)) > > + return ERR_PTR(-ENOENT); > > + > > + /* check queue reset status */ > > + if (vp_modern_get_queue_reset(mdev, queue_index) != 1) > > + return ERR_PTR(-EBUSY); > > + > > + vq = vp_enable_reset_vq(vdev, queue_index, callback, name, ctx); > > + if (IS_ERR(vq)) > > + return vq; > > + > > + vp_modern_set_queue_enable(&vp_dev->mdev, vq->index, true); > > + > > + msix_vec = vp_dev->vqs[queue_index]->msix_vector; > > + if (vp_dev->per_vq_vectors && msix_vec != VIRTIO_MSI_NO_VECTOR) > > + enable_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec)); > > + > > + return vq; > > +} > > + > > static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector) > > { > > return vp_modern_config_vector(&vp_dev->mdev, vector); > > @@ -395,6 +464,8 @@ static const struct virtio_config_ops virtio_pci_config_nodev_ops = { > > .set_vq_affinity = vp_set_vq_affinity, > > .get_vq_affinity = vp_get_vq_affinity, > > .get_shm_region = vp_get_shm_region, > > + .reset_vq = vp_modern_reset_vq, > > + .enable_reset_vq = vp_modern_enable_reset_vq, > > }; > > > > static const struct virtio_config_ops virtio_pci_config_ops = { > > @@ -413,6 +484,8 @@ static const struct virtio_config_ops virtio_pci_config_ops = { > > .set_vq_affinity = vp_set_vq_affinity, > > .get_vq_affinity = vp_get_vq_affinity, > > .get_shm_region = vp_get_shm_region, > > + .reset_vq = vp_modern_reset_vq, > > + .enable_reset_vq = vp_modern_enable_reset_vq, > > }; > > > > /* the PCI probing function */ > > -- > > 2.31.0 >