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Subject[RFC PATCH v2 19/19] vdpasim: control virtqueue support
Date
This patch introduces the control virtqueue support for vDPA
simulator. This is a requirement for supporting advanced features like
multiqueue.

A requirement for control virtqueue is to isolate its memory access
from the rx/tx virtqueues. This is because when using vDPA device
for VM, the control virqueue is not directly assigned to VM. Userspace
(Qemu) will present a shadow control virtqueue to control for
recording the device states.

The isolation is done via the virtqueue groups and ASID support in
vDPA through vhost-vdpa. The simulator is extended to have:

1) three virtqueues: RXVQ, TXVQ and CVQ (control virtqueue)
2) two virtqueue groups: group 0 contains RXVQ and TXVQ; group 1
contains CVQ
3) two address spaces and the simulator simply implements the address
spaces by mapping it 1:1 to IOTLB.

For the VM use cases, userspace(Qemu) may set AS 0 to group 0 and AS 1
to group 1. So we have:

1) The IOTLB for virtqueue group 0 contains the mappings of guest, so
RX and TX can be assigned to guest directly.
2) The IOTLB for virtqueue group 1 contains the mappings of CVQ which
is the buffers that allocated and managed by VMM only. So CVQ of
vhost-vdpa is visible to VMM only. And Guest can not access the CVQ
of vhost-vdpa.

For the other use cases, since AS 0 is associated to all virtqueue
groups by default. All virtqueues share the same mapping by default.

To demonstrate the function, VIRITO_NET_F_CTRL_MACADDR is
implemented in the simulator for the driver to set mac address.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Gautam Dawar <gdawar@xilinx.com>
---
drivers/vdpa/vdpa_sim/vdpa_sim.c | 91 ++++++++++++++++++++++------
drivers/vdpa/vdpa_sim/vdpa_sim.h | 2 +
drivers/vdpa/vdpa_sim/vdpa_sim_net.c | 88 ++++++++++++++++++++++++++-
3 files changed, 161 insertions(+), 20 deletions(-)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index 659e2e2e4b0c..59611f18a3a8 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -96,11 +96,17 @@ static void vdpasim_do_reset(struct vdpasim *vdpasim)
{
int i;

- for (i = 0; i < vdpasim->dev_attr.nvqs; i++)
+ spin_lock(&vdpasim->iommu_lock);
+
+ for (i = 0; i < vdpasim->dev_attr.nvqs; i++) {
vdpasim_vq_reset(vdpasim, &vdpasim->vqs[i]);
+ vringh_set_iotlb(&vdpasim->vqs[i].vring, &vdpasim->iommu[0],
+ &vdpasim->iommu_lock);
+ }
+
+ for (i = 0; i < vdpasim->dev_attr.nas; i++)
+ vhost_iotlb_reset(&vdpasim->iommu[i]);

- spin_lock(&vdpasim->iommu_lock);
- vhost_iotlb_reset(vdpasim->iommu);
spin_unlock(&vdpasim->iommu_lock);

vdpasim->features = 0;
@@ -145,7 +151,7 @@ static dma_addr_t vdpasim_map_range(struct vdpasim *vdpasim, phys_addr_t paddr,
dma_addr = iova_dma_addr(&vdpasim->iova, iova);

spin_lock(&vdpasim->iommu_lock);
- ret = vhost_iotlb_add_range(vdpasim->iommu, (u64)dma_addr,
+ ret = vhost_iotlb_add_range(&vdpasim->iommu[0], (u64)dma_addr,
(u64)dma_addr + size - 1, (u64)paddr, perm);
spin_unlock(&vdpasim->iommu_lock);

@@ -161,7 +167,7 @@ static void vdpasim_unmap_range(struct vdpasim *vdpasim, dma_addr_t dma_addr,
size_t size)
{
spin_lock(&vdpasim->iommu_lock);
- vhost_iotlb_del_range(vdpasim->iommu, (u64)dma_addr,
+ vhost_iotlb_del_range(&vdpasim->iommu[0], (u64)dma_addr,
(u64)dma_addr + size - 1);
spin_unlock(&vdpasim->iommu_lock);

@@ -250,8 +256,9 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr)
else
ops = &vdpasim_config_ops;

- vdpasim = vdpa_alloc_device(struct vdpasim, vdpa, NULL, ops, 1,
- 1, dev_attr->name, false);
+ vdpasim = vdpa_alloc_device(struct vdpasim, vdpa, NULL, ops,
+ dev_attr->ngroups, dev_attr->nas,
+ dev_attr->name, false);
if (IS_ERR(vdpasim)) {
ret = PTR_ERR(vdpasim);
goto err_alloc;
@@ -278,16 +285,20 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr)
if (!vdpasim->vqs)
goto err_iommu;

- vdpasim->iommu = vhost_iotlb_alloc(max_iotlb_entries, 0);
+ vdpasim->iommu = kmalloc_array(vdpasim->dev_attr.nas,
+ sizeof(*vdpasim->iommu), GFP_KERNEL);
if (!vdpasim->iommu)
goto err_iommu;

+ for (i = 0; i < vdpasim->dev_attr.nas; i++)
+ vhost_iotlb_init(&vdpasim->iommu[i], 0, 0);
+
vdpasim->buffer = kvmalloc(dev_attr->buffer_size, GFP_KERNEL);
if (!vdpasim->buffer)
goto err_iommu;

for (i = 0; i < dev_attr->nvqs; i++)
- vringh_set_iotlb(&vdpasim->vqs[i].vring, vdpasim->iommu,
+ vringh_set_iotlb(&vdpasim->vqs[i].vring, &vdpasim->iommu[0],
&vdpasim->iommu_lock);

ret = iova_cache_get();
@@ -401,7 +412,11 @@ static u32 vdpasim_get_vq_align(struct vdpa_device *vdpa)

static u32 vdpasim_get_vq_group(struct vdpa_device *vdpa, u16 idx)
{
- return 0;
+ /* RX and TX belongs to group 0, CVQ belongs to group 1 */
+ if (idx == 2)
+ return 1;
+ else
+ return 0;
}

static u64 vdpasim_get_device_features(struct vdpa_device *vdpa)
@@ -539,20 +554,53 @@ static struct vdpa_iova_range vdpasim_get_iova_range(struct vdpa_device *vdpa)
return range;
}

+static int vdpasim_set_group_asid(struct vdpa_device *vdpa, unsigned int group,
+ unsigned int asid)
+{
+ struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
+ struct vhost_iotlb *iommu;
+ int i;
+
+ if (group > vdpasim->dev_attr.ngroups)
+ return -EINVAL;
+
+ if (asid > vdpasim->dev_attr.nas)
+ return -EINVAL;
+
+ iommu = &vdpasim->iommu[asid];
+
+ spin_lock(&vdpasim->lock);
+
+ for (i = 0; i < vdpasim->dev_attr.nvqs; i++)
+ if (vdpasim_get_vq_group(vdpa, i) == group)
+ vringh_set_iotlb(&vdpasim->vqs[i].vring, &vdpasim->iommu[0],
+ &vdpasim->iommu_lock);
+
+ spin_unlock(&vdpasim->lock);
+
+ return 0;
+}
+
static int vdpasim_set_map(struct vdpa_device *vdpa, unsigned int asid,
struct vhost_iotlb *iotlb)
{
struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
struct vhost_iotlb_map *map;
+ struct vhost_iotlb *iommu;
u64 start = 0ULL, last = 0ULL - 1;
int ret;

+ if (asid >= vdpasim->dev_attr.nas)
+ return -EINVAL;
+
spin_lock(&vdpasim->iommu_lock);
- vhost_iotlb_reset(vdpasim->iommu);
+
+ iommu = &vdpasim->iommu[asid];
+ vhost_iotlb_reset(iommu);

for (map = vhost_iotlb_itree_first(iotlb, start, last); map;
map = vhost_iotlb_itree_next(map, start, last)) {
- ret = vhost_iotlb_add_range(vdpasim->iommu, map->start,
+ ret = vhost_iotlb_add_range(iommu, map->start,
map->last, map->addr, map->perm);
if (ret)
goto err;
@@ -561,7 +609,7 @@ static int vdpasim_set_map(struct vdpa_device *vdpa, unsigned int asid,
return 0;

err:
- vhost_iotlb_reset(vdpasim->iommu);
+ vhost_iotlb_reset(iommu);
spin_unlock(&vdpasim->iommu_lock);
return ret;
}
@@ -573,9 +621,12 @@ static int vdpasim_dma_map(struct vdpa_device *vdpa, unsigned int asid,
struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
int ret;

+ if (asid >= vdpasim->dev_attr.nas)
+ return -EINVAL;
+
spin_lock(&vdpasim->iommu_lock);
- ret = vhost_iotlb_add_range_ctx(vdpasim->iommu, iova, iova + size - 1,
- pa, perm, opaque);
+ ret = vhost_iotlb_add_range_ctx(&vdpasim->iommu[asid], iova,
+ iova + size - 1, pa, perm, opaque);
spin_unlock(&vdpasim->iommu_lock);

return ret;
@@ -586,8 +637,11 @@ static int vdpasim_dma_unmap(struct vdpa_device *vdpa, unsigned int asid,
{
struct vdpasim *vdpasim = vdpa_to_sim(vdpa);

+ if (asid >= vdpasim->dev_attr.nas)
+ return -EINVAL;
+
spin_lock(&vdpasim->iommu_lock);
- vhost_iotlb_del_range(vdpasim->iommu, iova, iova + size - 1);
+ vhost_iotlb_del_range(&vdpasim->iommu[asid], iova, iova + size - 1);
spin_unlock(&vdpasim->iommu_lock);

return 0;
@@ -611,8 +665,7 @@ static void vdpasim_free(struct vdpa_device *vdpa)
}

kvfree(vdpasim->buffer);
- if (vdpasim->iommu)
- vhost_iotlb_free(vdpasim->iommu);
+ vhost_iotlb_free(vdpasim->iommu);
kfree(vdpasim->vqs);
kfree(vdpasim->config);
}
@@ -643,6 +696,7 @@ static const struct vdpa_config_ops vdpasim_config_ops = {
.set_config = vdpasim_set_config,
.get_generation = vdpasim_get_generation,
.get_iova_range = vdpasim_get_iova_range,
+ .set_group_asid = vdpasim_set_group_asid,
.dma_map = vdpasim_dma_map,
.dma_unmap = vdpasim_dma_unmap,
.free = vdpasim_free,
@@ -674,6 +728,7 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops = {
.set_config = vdpasim_set_config,
.get_generation = vdpasim_get_generation,
.get_iova_range = vdpasim_get_iova_range,
+ .set_group_asid = vdpasim_set_group_asid,
.set_map = vdpasim_set_map,
.free = vdpasim_free,
};
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
index 0be7c1e7ef80..622782e92239 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
@@ -41,6 +41,8 @@ struct vdpasim_dev_attr {
size_t buffer_size;
int nvqs;
u32 id;
+ u32 ngroups;
+ u32 nas;

work_func_t work_fn;
void (*get_config)(struct vdpasim *vdpasim, void *config);
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
index ed5ade4ae570..513970c05af2 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
@@ -26,10 +26,15 @@
#define DRV_LICENSE "GPL v2"

#define VDPASIM_NET_FEATURES (VDPASIM_FEATURES | \
+ (1ULL << VIRTIO_NET_F_MTU) | \
(1ULL << VIRTIO_NET_F_MAC) | \
- (1ULL << VIRTIO_NET_F_MTU));
+ (1ULL << VIRTIO_NET_F_CTRL_VQ) | \
+ (1ULL << VIRTIO_NET_F_CTRL_MAC_ADDR));

-#define VDPASIM_NET_VQ_NUM 2
+/* 3 virtqueues, 2 address spaces, 2 virtqueue groups */
+#define VDPASIM_NET_VQ_NUM 3
+#define VDPASIM_NET_AS_NUM 2
+#define VDPASIM_NET_GROUP_NUM 2

static void vdpasim_net_complete(struct vdpasim_virtqueue *vq, size_t len)
{
@@ -63,6 +68,81 @@ static bool receive_filter(struct vdpasim *vdpasim, size_t len)
return false;
}

+static virtio_net_ctrl_ack vdpasim_handle_ctrl_mac(struct vdpasim *vdpasim,
+ u8 cmd)
+{
+ struct vdpasim_virtqueue *cvq = &vdpasim->vqs[2];
+ virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
+ size_t read;
+
+ switch (cmd) {
+ case VIRTIO_NET_CTRL_MAC_ADDR_SET:
+ read = vringh_iov_pull_iotlb(&cvq->vring, &cvq->in_iov,
+ (void *)vdpasim->config.mac,
+ ETH_ALEN);
+ if (read == ETH_ALEN)
+ status = VIRTIO_NET_OK;
+ break;
+ default:
+ break;
+ }
+
+ return status;
+}
+
+static void vdpasim_handle_cvq(struct vdpasim *vdpasim)
+{
+ struct vdpasim_virtqueue *cvq = &vdpasim->vqs[2];
+ virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
+ struct virtio_net_ctrl_hdr ctrl;
+ size_t read, write;
+ int err;
+
+ if (!(vdpasim->features & (1ULL << VIRTIO_NET_F_CTRL_VQ)))
+ return;
+
+ if (!cvq->ready)
+ return;
+
+ while (true) {
+ err = vringh_getdesc_iotlb(&cvq->vring, &cvq->in_iov,
+ &cvq->out_iov,
+ &cvq->head, GFP_ATOMIC);
+ if (err <= 0)
+ break;
+
+ read = vringh_iov_pull_iotlb(&cvq->vring, &cvq->in_iov, &ctrl,
+ sizeof(ctrl));
+ if (read != sizeof(ctrl))
+ break;
+
+ switch (ctrl.class) {
+ case VIRTIO_NET_CTRL_MAC:
+ status = vdpasim_handle_ctrl_mac(vdpasim, ctrl.cmd);
+ break;
+ default:
+ break;
+ }
+
+ /* Make sure data is wrote before advancing index */
+ smp_wmb();
+
+ write = vringh_iov_push_iotlb(&cvq->vring, &cvq->out_iov,
+ &status, sizeof(status));
+ vringh_complete_iotlb(&cvq->vring, cvq->head, write);
+ vringh_kiov_cleanup(&cvq->in_iov);
+ vringh_kiov_cleanup(&cvq->out_iov);
+
+ /* Make sure used is visible before rasing the interrupt. */
+ smp_wmb();
+
+ local_bh_disable();
+ if (cvq->cb)
+ cvq->cb(cvq->private);
+ local_bh_enable();
+ }
+}
+
static void vdpasim_net_work(struct work_struct *work)
{
struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
@@ -77,6 +157,8 @@ static void vdpasim_net_work(struct work_struct *work)
if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
goto out;

+ vdpasim_handle_cvq(vdpasim);
+
if (!txq->ready || !rxq->ready)
goto out;

@@ -162,6 +244,8 @@ static int vdpasim_net_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
dev_attr.id = VIRTIO_ID_NET;
dev_attr.supported_features = VDPASIM_NET_FEATURES;
dev_attr.nvqs = VDPASIM_NET_VQ_NUM;
+ dev_attr.ngroups = VDPASIM_NET_GROUP_NUM;
+ dev_attr.nas = VDPASIM_NET_AS_NUM;
dev_attr.config_size = sizeof(struct virtio_net_config);
dev_attr.get_config = vdpasim_net_get_config;
dev_attr.work_fn = vdpasim_net_work;
--
2.25.0
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