In order to reduce excessive memory mapping cost in live migration and
VM reboot, it is desirable to decouple the vhost-vdpa IOTLB abstraction
from the virtio device life cycle, i.e. mappings can be kept intact
across virtio device reset. Leverage the .reset_map callback, which is
meant to destroy the iotlb on the given ASID and recreate the 1:1
passthrough/identity mapping. To be consistent, the mapping on device
creation is initiailized to passthrough/identity with PA 1:1 mapped as
IOVA. With this the device .reset op doesn't have to maintain and clean
up memory mappings by itself.
Additionally, implement .compat_reset to cater for older userspace,
which may wish to see mapping to be cleared during reset.
Signed-off-by: Si-Wei Liu <si-wei.liu@xxxxxxxxxx>
Tested-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
---
drivers/vdpa/vdpa_sim/vdpa_sim.c | 52 ++++++++++++++++++++++++++------
1 file changed, 43 insertions(+), 9 deletions(-)
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index 76d41058add9..be2925d0d283 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -139,7 +139,7 @@ static void vdpasim_vq_reset(struct vdpasim *vdpasim,
vq->vring.notify = NULL;
}
-static void vdpasim_do_reset(struct vdpasim *vdpasim)
+static void vdpasim_do_reset(struct vdpasim *vdpasim, u32 flags)
{
int i;
@@ -151,11 +151,13 @@ static void vdpasim_do_reset(struct vdpasim *vdpasim)
&vdpasim->iommu_lock);
}
- for (i = 0; i < vdpasim->dev_attr.nas; i++) {
- vhost_iotlb_reset(&vdpasim->iommu[i]);
- vhost_iotlb_add_range(&vdpasim->iommu[i], 0, ULONG_MAX,
- 0, VHOST_MAP_RW);
- vdpasim->iommu_pt[i] = true;
+ if (flags & VDPA_RESET_F_CLEAN_MAP) {
+ for (i = 0; i < vdpasim->dev_attr.nas; i++) {
+ vhost_iotlb_reset(&vdpasim->iommu[i]);
+ vhost_iotlb_add_range(&vdpasim->iommu[i], 0, ULONG_MAX,
+ 0, VHOST_MAP_RW);
+ vdpasim->iommu_pt[i] = true;
+ }
}
vdpasim->running = true;
@@ -259,8 +261,12 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
if (!vdpasim->iommu_pt)
goto err_iommu;
- for (i = 0; i < vdpasim->dev_attr.nas; i++)
+ for (i = 0; i < vdpasim->dev_attr.nas; i++) {
vhost_iotlb_init(&vdpasim->iommu[i], max_iotlb_entries, 0);
+ vhost_iotlb_add_range(&vdpasim->iommu[i], 0, ULONG_MAX, 0,
+ VHOST_MAP_RW);
+ vdpasim->iommu_pt[i] = true;
+ }
for (i = 0; i < dev_attr->nvqs; i++)
vringh_set_iotlb(&vdpasim->vqs[i].vring, &vdpasim->iommu[0],
@@ -480,18 +486,23 @@ static void vdpasim_set_status(struct vdpa_device *vdpa, u8 status)
mutex_unlock(&vdpasim->mutex);
}
-static int vdpasim_reset(struct vdpa_device *vdpa)
+static int vdpasim_compat_reset(struct vdpa_device *vdpa, u32 flags)
{
struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
mutex_lock(&vdpasim->mutex);
vdpasim->status = 0;
- vdpasim_do_reset(vdpasim);
+ vdpasim_do_reset(vdpasim, flags);
mutex_unlock(&vdpasim->mutex);
return 0;
}
+static int vdpasim_reset(struct vdpa_device *vdpa)
+{
+ return vdpasim_compat_reset(vdpa, 0);
+}
+
static int vdpasim_suspend(struct vdpa_device *vdpa)
{
struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
@@ -637,6 +648,25 @@ static int vdpasim_set_map(struct vdpa_device *vdpa, unsigned int asid,
return ret;
}
+static int vdpasim_reset_map(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);
+ if (vdpasim->iommu_pt[asid])
+ goto out;
+ vhost_iotlb_reset(&vdpasim->iommu[asid]);
+ vhost_iotlb_add_range(&vdpasim->iommu[asid], 0, ULONG_MAX,
+ 0, VHOST_MAP_RW);
+ vdpasim->iommu_pt[asid] = true;
+out:
+ spin_unlock(&vdpasim->iommu_lock);
+ return 0;
+}
+
static int vdpasim_bind_mm(struct vdpa_device *vdpa, struct mm_struct *mm)
{
struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
@@ -749,6 +779,7 @@ static const struct vdpa_config_ops vdpasim_config_ops = {
.get_status = vdpasim_get_status,
.set_status = vdpasim_set_status,
.reset = vdpasim_reset,
+ .compat_reset = vdpasim_compat_reset,
.suspend = vdpasim_suspend,
.resume = vdpasim_resume,
.get_config_size = vdpasim_get_config_size,
@@ -759,6 +790,7 @@ static const struct vdpa_config_ops vdpasim_config_ops = {
.set_group_asid = vdpasim_set_group_asid,
.dma_map = vdpasim_dma_map,
.dma_unmap = vdpasim_dma_unmap,
+ .reset_map = vdpasim_reset_map,
.bind_mm = vdpasim_bind_mm,
.unbind_mm = vdpasim_unbind_mm,
.free = vdpasim_free,
@@ -787,6 +819,7 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops = {
.get_status = vdpasim_get_status,
.set_status = vdpasim_set_status,
.reset = vdpasim_reset,
+ .compat_reset = vdpasim_compat_reset,
.suspend = vdpasim_suspend,
.resume = vdpasim_resume,
.get_config_size = vdpasim_get_config_size,
@@ -796,6 +829,7 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops = {
.get_iova_range = vdpasim_get_iova_range,
.set_group_asid = vdpasim_set_group_asid,
.set_map = vdpasim_set_map,
+ .reset_map = vdpasim_reset_map,
.bind_mm = vdpasim_bind_mm,
.unbind_mm = vdpasim_unbind_mm,
.free = vdpasim_free,
--
2.39.3
_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
