Commit 86f6c224 authored by Si-Wei Liu's avatar Si-Wei Liu Committed by Michael S. Tsirkin
Browse files

vdpa_sim: implement .reset_map support 



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: default avatarSi-Wei Liu <si-wei.liu@oracle.com>
Tested-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Message-Id: <1697880319-4937-8-git-send-email-si-wei.liu@oracle.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Tested-by: default avatarLei Yang <leiyang@redhat.com>
parent 2eacf4b5

drivers/vdpa/vdpa_sim/vdpa_sim.c

+43 −9
Original line number Diff line number Diff line
@@ -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;
@@ -151,12 +151,14 @@ static void vdpasim_do_reset(struct vdpasim *vdpasim) 
				 &vdpasim->iommu_lock);

	}



	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;

	spin_unlock(&vdpasim->iommu_lock);
@@ -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,