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 <jasow...@redhat.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim.c | 189 +++++++++++++++++++++++++++----
 1 file changed, 166 insertions(+), 23 deletions(-)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index fe90a783bde4..0fd06ac491cd 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -60,14 +60,18 @@ struct vdpasim_virtqueue {
 #define VDPASIM_QUEUE_MAX 256
 #define VDPASIM_DEVICE_ID 0x1
 #define VDPASIM_VENDOR_ID 0
-#define VDPASIM_VQ_NUM 0x2
+#define VDPASIM_VQ_NUM 0x3
+#define VDPASIM_AS_NUM 0x2
+#define VDPASIM_GROUP_NUM 0x2
 #define VDPASIM_NAME "vdpasim-netdev"
 
 static u64 vdpasim_features = (1ULL << VIRTIO_F_ANY_LAYOUT) |
                              (1ULL << VIRTIO_F_VERSION_1)  |
                              (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
+                             (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);
 
 /* State of each vdpasim device */
 struct vdpasim {
@@ -147,11 +151,17 @@ static void vdpasim_reset(struct vdpasim *vdpasim)
 {
        int i;
 
-       for (i = 0; i < VDPASIM_VQ_NUM; i++)
+       spin_lock(&vdpasim->iommu_lock);
+
+       for (i = 0; i < VDPASIM_VQ_NUM; i++) {
                vdpasim_vq_reset(&vdpasim->vqs[i]);
+               vringh_set_iotlb(&vdpasim->vqs[i].vring,
+                                &vdpasim->iommu[0]);
+       }
 
-       spin_lock(&vdpasim->iommu_lock);
-       vhost_iotlb_reset(vdpasim->iommu);
+       for (i = 0; i < VDPASIM_AS_NUM; i++) {
+               vhost_iotlb_reset(&vdpasim->iommu[i]);
+       }
        spin_unlock(&vdpasim->iommu_lock);
 
        vdpasim->features = 0;
@@ -191,6 +201,81 @@ static bool receive_filter(struct vdpasim *vdpasim, size_t 
len)
        return false;
 }
 
+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_work(struct work_struct *work)
 {
        struct vdpasim *vdpasim = container_of(work, struct
@@ -276,7 +361,7 @@ static dma_addr_t vdpasim_map_page(struct device *dev, 
struct page *page,
                                   unsigned long attrs)
 {
        struct vdpasim *vdpasim = dev_to_sim(dev);
-       struct vhost_iotlb *iommu = vdpasim->iommu;
+       struct vhost_iotlb *iommu = &vdpasim->iommu[0];
        u64 pa = (page_to_pfn(page) << PAGE_SHIFT) + offset;
        int ret, perm = dir_to_perm(dir);
 
@@ -301,7 +386,7 @@ static void vdpasim_unmap_page(struct device *dev, 
dma_addr_t dma_addr,
                               unsigned long attrs)
 {
        struct vdpasim *vdpasim = dev_to_sim(dev);
-       struct vhost_iotlb *iommu = vdpasim->iommu;
+       struct vhost_iotlb *iommu = &vdpasim->iommu[0];
 
        spin_lock(&vdpasim->iommu_lock);
        vhost_iotlb_del_range(iommu, (u64)dma_addr,
@@ -314,7 +399,7 @@ static void *vdpasim_alloc_coherent(struct device *dev, 
size_t size,
                                    unsigned long attrs)
 {
        struct vdpasim *vdpasim = dev_to_sim(dev);
-       struct vhost_iotlb *iommu = vdpasim->iommu;
+       struct vhost_iotlb *iommu = &vdpasim->iommu[0];
        void *addr = kmalloc(size, flag);
        int ret;
 
@@ -344,7 +429,7 @@ static void vdpasim_free_coherent(struct device *dev, 
size_t size,
                                  unsigned long attrs)
 {
        struct vdpasim *vdpasim = dev_to_sim(dev);
-       struct vhost_iotlb *iommu = vdpasim->iommu;
+       struct vhost_iotlb *iommu = &vdpasim->iommu[0];
 
        spin_lock(&vdpasim->iommu_lock);
        vhost_iotlb_del_range(iommu, (u64)dma_addr,
@@ -370,14 +455,17 @@ static struct vdpasim *vdpasim_create(void)
        struct vdpasim *vdpasim;
        struct device *dev;
        int ret = -ENOMEM;
+       int i;
 
        if (batch_mapping)
                ops = &vdpasim_net_batch_config_ops;
        else
                ops = &vdpasim_net_config_ops;
 
+       /* 3 virtqueues, 2 address spaces, 2 virtqueue groups */
        vdpasim = vdpa_alloc_device(struct vdpasim, vdpa, NULL, ops,
-                                   VDPASIM_VQ_NUM, 1, 1);
+                                   VDPASIM_VQ_NUM, VDPASIM_AS_NUM,
+                                   VDPASIM_GROUP_NUM);
        if (!vdpasim)
                goto err_alloc;
 
@@ -391,10 +479,14 @@ static struct vdpasim *vdpasim_create(void)
                goto err_iommu;
        set_dma_ops(dev, &vdpasim_dma_ops);
 
-       vdpasim->iommu = vhost_iotlb_alloc(2048, 0);
+       vdpasim->iommu = kmalloc_array(VDPASIM_AS_NUM,
+                                      sizeof(*vdpasim->iommu), GFP_KERNEL);
        if (!vdpasim->iommu)
                goto err_iommu;
 
+       for (i = 0; i < VDPASIM_AS_NUM; i++)
+               vhost_iotlb_init(&vdpasim->iommu[i], 0, 0);
+
        vdpasim->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
        if (!vdpasim->buffer)
                goto err_iommu;
@@ -409,8 +501,9 @@ static struct vdpasim *vdpasim_create(void)
                eth_random_addr(vdpasim->config.mac);
        }
 
-       vringh_set_iotlb(&vdpasim->vqs[0].vring, vdpasim->iommu);
-       vringh_set_iotlb(&vdpasim->vqs[1].vring, vdpasim->iommu);
+       /* Make sure that default ASID is zero */
+       for (i = 0; i < VDPASIM_VQ_NUM; i++)
+               vringh_set_iotlb(&vdpasim->vqs[i].vring, &vdpasim->iommu[0]);
 
        vdpasim->vdpa.dma_dev = dev;
        ret = vdpa_register_device(&vdpasim->vdpa);
@@ -452,7 +545,14 @@ static void vdpasim_kick_vq(struct vdpa_device *vdpa, u16 
idx)
        struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
        struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
 
-       if (vq->ready)
+       if (idx == 2) {
+               /* Kernel virtio driver will do busy waiting for the
+                * result, so we can't handle cvq in the workqueue.
+                */
+               spin_lock(&vdpasim->lock);
+               vdpasim_handle_cvq(vdpasim);
+               spin_unlock(&vdpasim->lock);
+       } else if (vq->ready)
                schedule_work(&vdpasim->work);
 }
 
@@ -518,7 +618,11 @@ 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_features(struct vdpa_device *vdpa)
@@ -624,20 +728,52 @@ static struct vdpa_iova_range 
vdpasim_get_iova_range(struct vdpa_device *vdpa)
        return range;
 }
 
+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_GROUP_NUM)
+               return -EINVAL;
+
+       if (asid > VDPASIM_AS_NUM)
+               return -EINVAL;
+
+       iommu = &vdpasim->iommu[asid];
+
+       spin_lock(&vdpasim->lock);
+
+       for (i = 0; i < VDPASIM_VQ_NUM; i++)
+               if (vdpasim_get_vq_group(vdpa, i) == group)
+                       vringh_set_iotlb(&vdpasim->vqs[i].vring, iommu);
+
+       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_AS_NUM)
+               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;
@@ -646,7 +782,7 @@ 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;
 }
@@ -658,9 +794,12 @@ static int vdpasim_dma_map(struct vdpa_device *vdpa, 
unsigned int asid,
        struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
        int ret;
 
+       if (asid >= VDPASIM_AS_NUM)
+               return -EINVAL;
+
        spin_lock(&vdpasim->iommu_lock);
-       ret = vhost_iotlb_add_range(vdpasim->iommu, iova, iova + size - 1, pa,
-                                   perm);
+       ret = vhost_iotlb_add_range(&vdpasim->iommu[asid], iova,
+                                   iova + size - 1, pa, perm);
        spin_unlock(&vdpasim->iommu_lock);
 
        return ret;
@@ -671,8 +810,11 @@ static int vdpasim_dma_unmap(struct vdpa_device *vdpa, 
unsigned int asid,
 {
        struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 
+       if (asid >= VDPASIM_AS_NUM)
+               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;
@@ -684,8 +826,7 @@ static void vdpasim_free(struct vdpa_device *vdpa)
 
        cancel_work_sync(&vdpasim->work);
        kfree(vdpasim->buffer);
-       if (vdpasim->iommu)
-               vhost_iotlb_free(vdpasim->iommu);
+       vhost_iotlb_free(vdpasim->iommu);
 }
 
 static const struct vdpa_config_ops vdpasim_net_config_ops = {
@@ -711,6 +852,7 @@ static const struct vdpa_config_ops vdpasim_net_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,
@@ -739,6 +881,7 @@ static const struct vdpa_config_ops 
vdpasim_net_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,
 };
-- 
2.25.1

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