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virtio: Add vhost_svq_get_vring_addr

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It reports the shadow virtqueue address from qemu virtual address space.

Since this will be different from the guest's vaddr, but the device can
access it, SVQ takes special care about its alignment & lack of garbage
data. It assumes that IOMMU will work in host_page_size ranges for that.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
This commit is contained in:
Eugenio Pérez 2022-03-14 18:34:45 +01:00 • committed by Jason Wang
parent 4725a4181b
commit dafb34c992
2 changed files with 38 additions and 0 deletions
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29
hw/virtio/vhost-shadow-virtqueue.c
View file

@ -106,6 +106,35 @@ void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd)
}
}
/**
* Get the shadow vq vring address.
* @svq: Shadow virtqueue
* @addr: Destination to store address
*/
void vhost_svq_get_vring_addr(const VhostShadowVirtqueue *svq,
struct vhost_vring_addr *addr)
{
addr->desc_user_addr = (uint64_t)(intptr_t)svq->vring.desc;
addr->avail_user_addr = (uint64_t)(intptr_t)svq->vring.avail;
addr->used_user_addr = (uint64_t)(intptr_t)svq->vring.used;
}
size_t vhost_svq_driver_area_size(const VhostShadowVirtqueue *svq)
{
size_t desc_size = sizeof(vring_desc_t) * svq->vring.num;
size_t avail_size = offsetof(vring_avail_t, ring) +
sizeof(uint16_t) * svq->vring.num;
return ROUND_UP(desc_size + avail_size, qemu_real_host_page_size);
}
size_t vhost_svq_device_area_size(const VhostShadowVirtqueue *svq)
{
size_t used_size = offsetof(vring_used_t, ring) +
sizeof(vring_used_elem_t) * svq->vring.num;
return ROUND_UP(used_size, qemu_real_host_page_size);
}
/**
* Set a new file descriptor for the guest to kick the SVQ and notify for avail
*